adjust flow

Mega blast

.gitea/workflows/check.yml

@@ -1,9 +0,0 @@
-name: check
-on: [push]
-jobs:
-    check:
-        runs-on: ubuntu-latest
-        steps:
-            # actions/checkout v4.2.2, 2026-02-22
-            - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-            - run: docker build .

.gitignore

@@ -21,7 +21,9 @@ node_modules/
 *.key
 
 # Go build artifacts
-backend-go/bin/
+backend/bin/
+backend/api
+backend/poller
 *.exe
 *.exe~
 *.dll

.prettierignore

@@ -1,7 +1,7 @@
 node_modules/
 frontend/dist/
 frontend/build/
-backend-go/bin/
+backend/bin/
 *.lock
 Prompts/
 .claude/

LICENSE

@@ -2,8 +2,7 @@ MIT License
 
 Copyright (c) 2026 Steven Jannette
 
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is

Makefile

@@ -2,7 +2,7 @@
         test-go test-js lint-go lint-js fmt-go fmt-js fmt-check-go fmt-check-js \
         build-go build-js
 
-GODIR    := backend-go
+GODIR    := backend
 JSDIR    := frontend
 PRETTIER := $(JSDIR)/node_modules/.bin/prettier
 

README.md

@@ -28,8 +28,8 @@ make hooks
 cd frontend && npm install && cd ..
 
 # Copy and fill in environment variables
-cp backend-go/.env.example backend-go/.env
-# edit backend-go/.env with your DATABASE_URL, FIREBASE_PROJECT_ID, ETH_RPC_URL
+cp backend/.env.example backend/.env
+# edit backend/.env with your DATABASE_URL, FIREBASE_PROJECT_ID, ETH_RPC_URL
 
 # Run checks (requires golangci-lint)
 make check
@@ -38,7 +38,7 @@ make check
 make run
 
 # Start the poller (separate terminal)
-cd backend-go && go run ./cmd/poller
+cd backend && go run ./cmd/poller
 
 # Start the frontend dev server (separate terminal)
 cd frontend && npm run dev
@@ -63,7 +63,7 @@ frontend:
 
 ```
 koin_ping_0.2.0/
-├── backend-go/                # Go monorepo root
+├── backend/                # Go monorepo root
 │   ├── cmd/api/               # HTTP REST API server
 │   ├── cmd/poller/            # Blockchain polling daemon
 │   └── internal/

REPO_POLICIES.md

@@ -1,188 +0,0 @@
----
-title: Repository Policies
-last_modified: 2026-02-22
----
-
-This document covers repository structure, tooling, and workflow standards. Code
-style conventions are in separate documents:
-
-- [Code Styleguide](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/CODE_STYLEGUIDE.md)
-  (general, bash, Docker)
-- [Go](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/CODE_STYLEGUIDE_GO.md)
-- [JavaScript](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/CODE_STYLEGUIDE_JS.md)
-- [Python](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/CODE_STYLEGUIDE_PYTHON.md)
-- [Go HTTP Server Conventions](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/GO_HTTP_SERVER_CONVENTIONS.md)
-
----
-
-- Cross-project documentation (such as this file) must include
-  `last_modified: YYYY-MM-DD` in the YAML front matter so it can be kept in sync
-  with the authoritative source as policies evolve.
-
-- **ALL external references must be pinned by cryptographic hash.** This
-  includes Docker base images, Go modules, npm packages, GitHub Actions, and
-  anything else fetched from a remote source. Version tags (`@v4`, `@latest`,
-  `:3.21`, etc.) are server-mutable and therefore remote code execution
-  vulnerabilities. The ONLY acceptable way to reference an external dependency
-  is by its content hash (Docker `@sha256:...`, Go module hash in `go.sum`, npm
-  integrity hash in lockfile, GitHub Actions `@<commit-sha>`). No exceptions.
-  This also means never `curl | bash` to install tools like pyenv, nvm, rustup,
-  etc. Instead, download a specific release archive from GitHub, verify its hash
-  (hardcoded in the Dockerfile or script), and only then install. Unverified
-  install scripts are arbitrary remote code execution. This is the single most
-  important rule in this document. Double-check every external reference in
-  every file before committing. There are zero exceptions to this rule.
-
-- Every repo with software must have a root `Makefile` with these targets:
-  `make test`, `make lint`, `make fmt` (writes), `make fmt-check` (read-only),
-  `make check` (prereqs: `test`, `lint`, `fmt-check`), `make docker`, and
-  `make hooks` (installs pre-commit hook). A model Makefile is at
-  `https://git.eeqj.de/sneak/prompts/raw/branch/main/Makefile`.
-
-- Always use Makefile targets (`make fmt`, `make test`, `make lint`, etc.)
-  instead of invoking the underlying tools directly. The Makefile is the single
-  source of truth for how these operations are run.
-
-- The Makefile is authoritative documentation for how the repo is used. Beyond
-  the required targets above, it should have targets for every common operation:
-  running a local development server (`make run`, `make dev`), re-initializing
-  or migrating the database (`make db-reset`, `make migrate`), building
-  artifacts (`make build`), generating code, seeding data, or anything else a
-  developer would do regularly. If someone checks out the repo and types
-  `make<tab>`, they should see every meaningful operation available. A new
-  contributor should be able to understand the entire development workflow by
-  reading the Makefile.
-
-- Every repo should have a `Dockerfile`. All Dockerfiles must run `make check`
-  as a build step so the build fails if the branch is not green. For non-server
-  repos, the Dockerfile should bring up a development environment and run
-  `make check`. For server repos, `make check` should run as an early build
-  stage before the final image is assembled.
-
-- Every repo should have a Gitea Actions workflow (`.gitea/workflows/`) that
-  runs `docker build .` on push. Since the Dockerfile already runs `make check`,
-  a successful build implies all checks pass.
-
-- Use platform-standard formatters: `black` for Python, `prettier` for
-  JS/CSS/Markdown/HTML, `go fmt` for Go. Always use default configuration with
-  two exceptions: four-space indents (except Go), and `proseWrap: always` for
-  Markdown (hard-wrap at 80 columns). Documentation and writing repos (Markdown,
-  HTML, CSS) should also have `.prettierrc` and `.prettierignore`.
-
-- Pre-commit hook: `make check` if local testing is possible, otherwise
-  `make lint && make fmt-check`. The Makefile should provide a `make hooks`
-  target to install the pre-commit hook.
-
-- All repos with software must have tests that run via the platform-standard
-  test framework (`go test`, `pytest`, `jest`/`vitest`, etc.). If no meaningful
-  tests exist yet, add the most minimal test possible — e.g. importing the
-  module under test to verify it compiles/parses. There is no excuse for
-  `make test` to be a no-op.
-
-- `make test` must complete in under 20 seconds. Add a 30-second timeout in the
-  Makefile.
-
-- Docker builds must complete in under 5 minutes.
-
-- `make check` must not modify any files in the repo. Tests may use temporary
-  directories.
-
-- `main` must always pass `make check`, no exceptions.
-
-- Never commit secrets. `.env` files, credentials, API keys, and private keys
-  must be in `.gitignore`. No exceptions.
-
-- `.gitignore` should be comprehensive from the start: OS files (`.DS_Store`),
-  editor files (`.swp`, `*~`), language build artifacts, and `node_modules/`.
-  Fetch the standard `.gitignore` from
-  `https://git.eeqj.de/sneak/prompts/raw/branch/main/.gitignore` when setting up
-  a new repo.
-
-- Never use `git add -A` or `git add .`. Always stage files explicitly by name.
-
-- Never force-push to `main`.
-
-- Make all changes on a feature branch. You can do whatever you want on a
-  feature branch.
-
-- `.golangci.yml` is standardized and must _NEVER_ be modified by an agent, only
-  manually by the user. Fetch from
-  `https://git.eeqj.de/sneak/prompts/raw/branch/main/.golangci.yml`.
-
-- When pinning images or packages by hash, add a comment above the reference
-  with the version and date (YYYY-MM-DD).
-
-- Use `yarn`, not `npm`.
-
-- Write all dates as YYYY-MM-DD (ISO 8601).
-
-- Simple projects should be configured with environment variables.
-
-- Dockerized web services listen on port 8080 by default, overridable with
-  `PORT`.
-
-- `README.md` is the primary documentation. Required sections:
-    - **Description**: First line must include the project name, purpose,
-      category (web server, SPA, CLI tool, etc.), license, and author. Example:
-      "µPaaS is an MIT-licensed Go web application by @sneak that receives
-      git-frontend webhooks and deploys applications via Docker in realtime."
-    - **Getting Started**: Copy-pasteable install/usage code block.
-    - **Rationale**: Why does this exist?
-    - **Design**: How is the program structured?
-    - **TODO**: Update meticulously, even between commits. When planning, put
-      the todo list in the README so a new agent can pick up where the last one
-      left off.
-    - **License**: MIT, GPL, or WTFPL. Ask the user for new projects. Include a
-      `LICENSE` file in the repo root and a License section in the README.
-    - **Author**: [@sneak](https://sneak.berlin).
-
-- First commit of a new repo should contain only `README.md`.
-
-- Go module root: `sneak.berlin/go/<name>`. Always run `go mod tidy` before
-  committing.
-
-- Use SemVer.
-
-- Database migrations live in `internal/db/migrations/` and must be embedded in
-  the binary.
-    - `000_migration.sql` — contains ONLY the creation of the migrations
-      tracking table itself. Nothing else.
-    - `001_schema.sql` — the full application schema.
-    - **Pre-1.0.0:** never add additional migration files (002, 003, etc.).
-      There is no installed base to migrate. Edit `001_schema.sql` directly.
-    - **Post-1.0.0:** add new numbered migration files for each schema change.
-      Never edit existing migrations after release.
-
-- All repos should have an `.editorconfig` enforcing the project's indentation
-  settings.
-
-- Avoid putting files in the repo root unless necessary. Root should contain
-  only project-level config files (`README.md`, `Makefile`, `Dockerfile`,
-  `LICENSE`, `.gitignore`, `.editorconfig`, `REPO_POLICIES.md`, and
-  language-specific config). Everything else goes in a subdirectory. Canonical
-  subdirectory names:
-    - `bin/` — executable scripts and tools
-    - `cmd/` — Go command entrypoints
-    - `configs/` — configuration templates and examples
-    - `deploy/` — deployment manifests (k8s, compose, terraform)
-    - `docs/` — documentation and markdown (README.md stays in root)
-    - `internal/` — Go internal packages
-    - `internal/db/migrations/` — database migrations
-    - `pkg/` — Go library packages
-    - `share/` — systemd units, data files
-    - `static/` — static assets (images, fonts, etc.)
-    - `web/` — web frontend source
-
-- When setting up a new repo, files from the `prompts` repo may be used as
-  templates. Fetch them from
-  `https://git.eeqj.de/sneak/prompts/raw/branch/main/<path>`.
-
-- New repos must contain at minimum:
-    - `README.md`, `.git`, `.gitignore`, `.editorconfig`
-    - `LICENSE`, `REPO_POLICIES.md` (copy from the `prompts` repo)
-    - `Makefile`
-    - `Dockerfile`, `.dockerignore`
-    - `.gitea/workflows/check.yml`
-    - Go: `go.mod`, `go.sum`, `.golangci.yml`
-    - JS: `package.json`, `yarn.lock`, `.prettierrc`, `.prettierignore`
-    - Python: `pyproject.toml`

backend-go/.env.example

@@ -1,20 +0,0 @@
-# Server
-PORT=3001
-API_BASE_PATH=/v1
-NODE_ENV=development
-
-# Database
-DATABASE_URL=postgresql://user:password@localhost:5432/koin_ping
-
-# Ethereum JSON-RPC
-ETH_RPC_URL=https://mainnet.infura.io/v3/YOUR-PROJECT-ID
-
-# Polling interval (ms, minimum 1000)
-POLL_INTERVAL_MS=60000
-
-# Firebase
-FIREBASE_PROJECT_ID=koin-ping
-
-# Email notifications (Resend — https://resend.com)
-# RESEND_API_KEY=re_xxxxxxxxxxxx
-# EMAIL_FROM=Koin Ping <alerts@yourdomain.com>

backend-go/README.md

@@ -1,21 +0,0 @@
-Start DB:
-
-brew services start postgresql@15
-
-
-From the backend-go directory, you have a few options:
-
-Option 1: Single command (both API + poller)
-cd /Users/kjannette/workspace/koin_ping_0.2.0/backend-gomake dev-all
-
-Option 2: Two separate terminals
-Terminal 1 (API server):
-cd /Users/kjannette/workspace/koin_ping_0.2.0/backend-gogo run ./cmd/api
-Terminal 2 (Poller):
-cd /Users/kjannette/workspace/koin_ping_0.2.0/backend-gogo run ./cmd/poller
-
-make run — Builds and runs the API server.
-make dev — Runs the API server with auto-reload via air (falls back to go run if air isn't installed).
-make poller — Builds and runs the poller.
-make poller-dev — Runs the poller with auto-reload.
-make dev-all — Runs both the API and poller concurrently.

backend-go/internal/models/alert_rule.go

@@ -1,115 +0,0 @@
-package models
-
-import (
-	"context"
-	"errors"
-
-	"github.com/jackc/pgx/v5"
-	"github.com/jackc/pgx/v5/pgxpool"
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
-)
-
-type AlertRuleModel struct {
-	pool *pgxpool.Pool
-}
-
-func NewAlertRuleModel(pool *pgxpool.Pool) *AlertRuleModel {
-	return &AlertRuleModel{pool: pool}
-}
-
-func (m *AlertRuleModel) Create(ctx context.Context, addressID int, alertType domain.AlertType, threshold *float64) (*domain.AlertRule, error) {
-	var r domain.AlertRule
-	err := m.pool.QueryRow(ctx,
-		`INSERT INTO alert_rules (address_id, type, threshold, enabled)
-		 VALUES ($1, $2, $3, TRUE)
-		 RETURNING id, address_id, type, threshold, enabled, created_at`,
-		addressID, alertType.String(), threshold,
-	).Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Enabled, &r.CreatedAt)
-	if err != nil {
-		return nil, err
-	}
-	return &r, nil
-}
-
-func (m *AlertRuleModel) ListByAddress(ctx context.Context, addressID int) ([]domain.AlertRule, error) {
-	rows, err := m.pool.Query(ctx,
-		`SELECT id, address_id, type, threshold, enabled, created_at
-		 FROM alert_rules
-		 WHERE address_id = $1
-		 ORDER BY created_at DESC`,
-		addressID,
-	)
-	if err != nil {
-		return nil, err
-	}
-	defer rows.Close()
-
-	var rules []domain.AlertRule
-	for rows.Next() {
-		var r domain.AlertRule
-		if err := rows.Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Enabled, &r.CreatedAt); err != nil {
-			return nil, err
-		}
-		rules = append(rules, r)
-	}
-	return rules, rows.Err()
-}
-
-func (m *AlertRuleModel) FindByID(ctx context.Context, id int, userID *string) (*domain.AlertRule, error) {
-	var r domain.AlertRule
-	var err error
-
-	if userID != nil {
-		err = m.pool.QueryRow(ctx,
-			`SELECT ar.id, ar.address_id, ar.type, ar.threshold, ar.enabled, ar.created_at
-			 FROM alert_rules ar
-			 JOIN addresses a ON a.id = ar.address_id
-			 WHERE ar.id = $1 AND a.user_id = $2`,
-			id, *userID,
-		).Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Enabled, &r.CreatedAt)
-	} else {
-		err = m.pool.QueryRow(ctx,
-			`SELECT id, address_id, type, threshold, enabled, created_at
-			 FROM alert_rules
-			 WHERE id = $1`,
-			id,
-		).Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Enabled, &r.CreatedAt)
-	}
-
-	if err != nil {
-		if errors.Is(err, pgx.ErrNoRows) {
-			return nil, nil
-		}
-		return nil, err
-	}
-	return &r, nil
-}
-
-func (m *AlertRuleModel) UpdateEnabled(ctx context.Context, id int, enabled bool) (*domain.AlertRule, error) {
-	var r domain.AlertRule
-	err := m.pool.QueryRow(ctx,
-		`UPDATE alert_rules
-		 SET enabled = $2
-		 WHERE id = $1
-		 RETURNING id, address_id, type, threshold, enabled, created_at`,
-		id, enabled,
-	).Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Enabled, &r.CreatedAt)
-	if err != nil {
-		if errors.Is(err, pgx.ErrNoRows) {
-			return nil, nil
-		}
-		return nil, err
-	}
-	return &r, nil
-}
-
-func (m *AlertRuleModel) Remove(ctx context.Context, id int) (bool, error) {
-	tag, err := m.pool.Exec(ctx,
-		`DELETE FROM alert_rules WHERE id = $1`,
-		id,
-	)
-	if err != nil {
-		return false, err
-	}
-	return tag.RowsAffected() > 0, nil
-}

backend-go/internal/models/user.go

@@ -1,53 +0,0 @@
-package models
-
-import (
-	"context"
-	"errors"
-
-	"github.com/jackc/pgx/v5"
-	"github.com/jackc/pgx/v5/pgxpool"
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
-)
-
-type UserModel struct {
-	pool *pgxpool.Pool
-}
-
-func NewUserModel(pool *pgxpool.Pool) *UserModel {
-	return &UserModel{pool: pool}
-}
-
-// FindOrCreateByFirebaseUID returns the local user for a Firebase UID,
-// creating one if it doesn't exist yet. On conflict (returning user) the
-// updated_at timestamp is refreshed.
-func (m *UserModel) FindOrCreateByFirebaseUID(ctx context.Context, firebaseUID, email string) (*domain.User, error) {
-	var u domain.User
-	err := m.pool.QueryRow(ctx,
-		`INSERT INTO users (firebase_uid, email)
-		 VALUES ($1, $2)
-		 ON CONFLICT (firebase_uid) DO UPDATE SET updated_at = NOW()
-		 RETURNING id, firebase_uid, email, display_name, created_at, updated_at`,
-		firebaseUID, email,
-	).Scan(&u.ID, &u.FirebaseUID, &u.Email, &u.DisplayName, &u.CreatedAt, &u.UpdatedAt)
-	if err != nil {
-		return nil, err
-	}
-	return &u, nil
-}
-
-func (m *UserModel) GetByID(ctx context.Context, id string) (*domain.User, error) {
-	var u domain.User
-	err := m.pool.QueryRow(ctx,
-		`SELECT id, firebase_uid, email, display_name, created_at, updated_at
-		 FROM users
-		 WHERE id = $1`,
-		id,
-	).Scan(&u.ID, &u.FirebaseUID, &u.Email, &u.DisplayName, &u.CreatedAt, &u.UpdatedAt)
-	if err != nil {
-		if errors.Is(err, pgx.ErrNoRows) {
-			return nil, nil
-		}
-		return nil, err
-	}
-	return &u, nil
-}

backend-go/internal/notifications/notifier.go

@@ -1,16 +0,0 @@
-package notifications
-
-import "context"
-
-// AlertMetadata holds context about the alert being sent.
-type AlertMetadata struct {
-	TxHash       string
-	AddressLabel string
-	AlertType    string
-	Address      string
-}
-
-// Notifier is the interface implemented by all notification channels.
-type Notifier interface {
-	Send(ctx context.Context, message string, meta AlertMetadata) error
-}

backend/Makefile

@@ -37,7 +37,7 @@ tidy:
 
 # Database setup
 db-setup:
-	psql -d koin_ping_dev -f infra/schema.sql
+	psql -d koin_ping -f infra/schema.sql
 
 vet:
 	go vet ./...

backend/README.md

@@ -0,0 +1,32 @@
+Backend startup quickstarat:
+----------------------------->  BEST
+## 1. brew services start postgresql@15
+
+          OR 
+
+      /opt/homebrew/opt/postgresql@15/bin/pg_ctl -D /opt/homebrew/var/postgresql@15 start
+
+## 2.   ALLIN ONE: 
+        Make dev-all — Runs both the API and poller concurrently.
+----------------------------->  BEST
+
+          - OR - 
+          
+           
+## 3.  Option 1: Single command (both API + poller)
+       cd /Users/kjannette/workspace/koin_ping_0.2.0/backendmake dev-all
+
+## 4.   Option 2: Two separate terminals
+        Terminal 1 (API server):
+        cd /Users/kjannette/workspace/koin_ping_0.2.0/backend go run ./cmd/api
+        
+        make run — Builds and runs the API server.
+        make dev — Runs the API server with auto-reload via air (falls back to go run if air isn't installed).
+
+## 5.   Terminal 2 (Poller):
+        cd /Users/kjannette/workspace/koin_ping_0.2.0/backend 
+        go run ./cmd/poller
+
+        make poller — Builds and runs the poller.
+        make poller-dev — Runs the poller with auto-reload.
+

backend/cmd/api/main.go

@@ -8,13 +8,13 @@ import (
 	"time"
 
 	"github.com/joho/godotenv"
-	"github.com/kjannette/koin-ping/backend-go/internal/config"
-	"github.com/kjannette/koin-ping/backend-go/internal/database"
-	"github.com/kjannette/koin-ping/backend-go/internal/firebase"
-	"github.com/kjannette/koin-ping/backend-go/internal/handlers"
-	"github.com/kjannette/koin-ping/backend-go/internal/middleware"
-	"github.com/kjannette/koin-ping/backend-go/internal/models"
-	"github.com/kjannette/koin-ping/backend-go/internal/services"
+	"github.com/kjannette/koin-ping/backend/internal/config"
+	"github.com/kjannette/koin-ping/backend/internal/database"
+	"github.com/kjannette/koin-ping/backend/internal/firebase"
+	"github.com/kjannette/koin-ping/backend/internal/handlers"
+	"github.com/kjannette/koin-ping/backend/internal/middleware"
+	"github.com/kjannette/koin-ping/backend/internal/models"
+	"github.com/kjannette/koin-ping/backend/internal/services"
 )
 
 const (
@@ -55,14 +55,22 @@ func main() {
 		cfg.ResendAPIKey, cfg.EmailFrom, alertEventModel, notifConfigModel,
 	)
 
-	addressHandler := handlers.NewAddressHandler(addressModel)
-	alertRuleHandler := handlers.NewAlertRuleHandler(alertRuleModel, addressModel)
+	addressHandler := handlers.NewAddressHandler(addressModel, userModel)
+	alertRuleHandler := handlers.NewAlertRuleHandler(alertRuleModel, addressModel, userModel)
 	alertEventHandler := handlers.NewAlertEventHandler(alertEventModel)
-	notifConfigHandler := handlers.NewNotificationConfigHandler(notifConfigModel, cfg)
+	notifConfigHandler := handlers.NewNotificationConfigHandler(notifConfigModel, userModel, cfg)
 	emailDigestHandler := handlers.NewEmailDigestHandler(emailDigestSvc, notifConfigModel)
 	statusHandler := handlers.NewStatusHandler(checkpointModel)
+	stripeHandler := handlers.NewStripeHandler(userModel, cfg)
+	accountHandler := handlers.NewAccountHandler(userModel, addressModel, cfg)
 
 	authenticate := middleware.Authenticate(userModel)
+	requireSub := middleware.RequireSubscription(userModel)
+
+	// authAndSub chains authentication + subscription check for protected routes.
+	authAndSub := func(h http.Handler) http.Handler {
+		return authenticate(requireSub(h))
+	}
 
 	mux := http.NewServeMux()
 	b := cfg.APIBasePath // e.g. "/v1"
@@ -71,45 +79,67 @@ func main() {
 	mux.HandleFunc("GET "+b+"/health", handlers.HealthCheck)
 	mux.HandleFunc("GET "+b+"/status", statusHandler.GetStatus)
 
-	// Authenticated routes — addresses
+	// Stripe webhook (public — called by Stripe, not authenticated)
+	mux.HandleFunc("POST "+b+"/stripe/webhook", stripeHandler.HandleWebhook)
+
+	// Onboarding checkout (public — account doesn't exist yet)
+	mux.HandleFunc("POST "+b+"/stripe/create-onboarding-checkout", stripeHandler.CreateOnboardingCheckout)
+
+	// Stripe routes (auth required, NO subscription required)
+	mux.Handle("POST "+b+"/stripe/create-checkout-session",
+		authenticate(http.HandlerFunc(stripeHandler.CreateCheckoutSession)))
+	mux.Handle("GET "+b+"/stripe/subscription-status",
+		authenticate(http.HandlerFunc(stripeHandler.GetSubscriptionStatus)))
+	mux.Handle("POST "+b+"/stripe/verify-checkout",
+		authenticate(http.HandlerFunc(stripeHandler.VerifyCheckoutSession)))
+	mux.Handle("POST "+b+"/stripe/create-portal-session",
+		authenticate(http.HandlerFunc(stripeHandler.CreatePortalSession)))
+	mux.Handle("POST "+b+"/stripe/activate-free",
+		authenticate(http.HandlerFunc(stripeHandler.ActivateFreeTier)))
+
+	// Account route (auth required, NO subscription required)
+	mux.Handle("GET "+b+"/user/account",
+		authenticate(http.HandlerFunc(accountHandler.GetAccount)))
+
+	// Authenticated + subscribed routes — addresses
 	mux.Handle("POST "+b+"/addresses",
-		authenticate(http.HandlerFunc(addressHandler.Create)))
+		authAndSub(http.HandlerFunc(addressHandler.Create)))
 	mux.Handle("GET "+b+"/addresses",
-		authenticate(http.HandlerFunc(addressHandler.List)))
+		authAndSub(http.HandlerFunc(addressHandler.List)))
 	mux.Handle("DELETE "+b+"/addresses/{addressId}",
-		authenticate(http.HandlerFunc(addressHandler.Remove)))
+		authAndSub(http.HandlerFunc(addressHandler.Remove)))
 	mux.Handle("PATCH "+b+"/addresses/{addressId}",
-		authenticate(http.HandlerFunc(addressHandler.UpdateLabel)))
+		authAndSub(http.HandlerFunc(addressHandler.UpdateLabel)))
 
-	// Authenticated routes for alert rules
+	// Authenticated + subscribed routes — alert rules
 	mux.Handle("POST "+b+"/addresses/{addressId}/alerts",
-		authenticate(http.HandlerFunc(alertRuleHandler.Create)))
+		authAndSub(http.HandlerFunc(alertRuleHandler.Create)))
 	mux.Handle("GET "+b+"/addresses/{addressId}/alerts",
-		authenticate(http.HandlerFunc(alertRuleHandler.ListByAddress)))
+		authAndSub(http.HandlerFunc(alertRuleHandler.ListByAddress)))
 	mux.Handle("PATCH "+b+"/alerts/{alertId}",
-		authenticate(http.HandlerFunc(alertRuleHandler.UpdateStatus)))
+		authAndSub(http.HandlerFunc(alertRuleHandler.UpdateStatus)))
 	mux.Handle("DELETE "+b+"/alerts/{alertId}",
-		authenticate(http.HandlerFunc(alertRuleHandler.Remove)))
+		authAndSub(http.HandlerFunc(alertRuleHandler.Remove)))
 
-	// Authenticated routes — alert events
+	// Authenticated + subscribed routes — alert events
 	mux.Handle("GET "+b+"/alert-events",
-		authenticate(http.HandlerFunc(alertEventHandler.List)))
+		authAndSub(http.HandlerFunc(alertEventHandler.List)))
 
-	// Authenticated routes — notification config
+	// Authenticated + subscribed routes — notification config
 	mux.Handle("GET "+b+"/notification-config",
-		authenticate(http.HandlerFunc(notifConfigHandler.GetConfig)))
+		authAndSub(http.HandlerFunc(notifConfigHandler.GetConfig)))
 	mux.Handle("PUT "+b+"/notification-config",
-		authenticate(http.HandlerFunc(notifConfigHandler.UpdateConfig)))
+		authAndSub(http.HandlerFunc(notifConfigHandler.UpdateConfig)))
 	mux.Handle("DELETE "+b+"/notification-config",
-		authenticate(http.HandlerFunc(notifConfigHandler.DeleteConfig)))
+		authAndSub(http.HandlerFunc(notifConfigHandler.DeleteConfig)))
 	mux.Handle("POST "+b+"/notification-config/test",
-		authenticate(http.HandlerFunc(notifConfigHandler.TestChannels)))
+		authAndSub(http.HandlerFunc(notifConfigHandler.TestChannels)))
 
-	// Authenticated routes — email digest
+	// Authenticated + subscribed routes — email digest
 	mux.Handle("POST "+b+"/email/setup",
-		authenticate(http.HandlerFunc(emailDigestHandler.SetupEmail)))
+		authAndSub(http.HandlerFunc(emailDigestHandler.SetupEmail)))
 	mux.Handle("POST "+b+"/email/digest",
-		authenticate(http.HandlerFunc(emailDigestHandler.SendDigest)))
+		authAndSub(http.HandlerFunc(emailDigestHandler.SendDigest)))
 
 	handler := corsMiddleware(mux)
 

backend/cmd/poller/main.go

@@ -12,11 +12,11 @@ import (
 	"time"
 
 	"github.com/joho/godotenv"
-	"github.com/kjannette/koin-ping/backend-go/internal/config"
-	"github.com/kjannette/koin-ping/backend-go/internal/database"
-	"github.com/kjannette/koin-ping/backend-go/internal/models"
-	"github.com/kjannette/koin-ping/backend-go/internal/protocols/ethereum"
-	"github.com/kjannette/koin-ping/backend-go/internal/services"
+	"github.com/kjannette/koin-ping/backend/internal/config"
+	"github.com/kjannette/koin-ping/backend/internal/database"
+	"github.com/kjannette/koin-ping/backend/internal/models"
+	"github.com/kjannette/koin-ping/backend/internal/protocols/ethereum"
+	"github.com/kjannette/koin-ping/backend/internal/services"
 )
 
 const (
@@ -51,6 +51,7 @@ func main() {
 
 	defer database.Close()
 
+	userModel := models.NewUserModel(pool)
 	addressModel := models.NewAddressModel(pool)
 	alertRuleModel := models.NewAlertRuleModel(pool)
 	alertEventModel := models.NewAlertEventModel(pool)
@@ -59,8 +60,7 @@ func main() {
 
 	observer := services.NewObserverService(eth, addressModel, checkpointModel)
 	evaluator := services.NewEvaluatorService(
-		eth, alertRuleModel, alertEventModel, addressModel, notifConfigModel,
-		cfg.ResendAPIKey, cfg.EmailFrom,
+		eth, alertRuleModel, alertEventModel, addressModel, userModel, notifConfigModel,
 	)
 	digestSvc := services.NewEmailDigestService(cfg.ResendAPIKey, cfg.EmailFrom, alertEventModel, notifConfigModel)
 
@@ -138,6 +138,8 @@ func runCycle(
 		return
 	}
 
+	evaluator.WaitForNotifications()
+
 	duration := time.Since(startTime)
 	log.Printf("[%s] Cycle complete: %d observations, %d alerts fired in %s",
 		time.Now().UTC().Format(time.RFC3339),

backend/go.mod

@@ -1,4 +1,4 @@
-module github.com/kjannette/koin-ping/backend-go
+module github.com/kjannette/koin-ping/backend
 
 go 1.25.0
 
@@ -44,6 +44,7 @@ require (
 	github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10 // indirect
 	github.com/resend/resend-go/v3 v3.1.1 // indirect
 	github.com/spiffe/go-spiffe/v2 v2.6.0 // indirect
+	github.com/stripe/stripe-go/v82 v82.5.1 // indirect
 	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
 	go.opentelemetry.io/contrib/detectors/gcp v1.39.0 // indirect
 	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.61.0 // indirect

backend/go.sum

@@ -101,6 +101,8 @@ github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UV
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+github.com/stripe/stripe-go/v82 v82.5.1 h1:05q6ZDKoe8PLMpQV072obF74HCgP4XJeJYoNuRSX2+8=
+github.com/stripe/stripe-go/v82 v82.5.1/go.mod h1:majCQX6AfObAvJiHraPi/5udwHi4ojRvJnnxckvHrX8=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
 go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=

backend/infra/migrations/007_add_stripe_to_users.sql

@@ -0,0 +1,8 @@
+-- Migration 007: Add Stripe subscription fields to users table
+
+ALTER TABLE users ADD COLUMN IF NOT EXISTS stripe_customer_id VARCHAR(255);
+ALTER TABLE users ADD COLUMN IF NOT EXISTS stripe_subscription_id VARCHAR(255);
+ALTER TABLE users ADD COLUMN IF NOT EXISTS subscription_status VARCHAR(50) DEFAULT 'none';
+ALTER TABLE users ADD COLUMN IF NOT EXISTS subscription_created_at TIMESTAMP;
+
+CREATE INDEX IF NOT EXISTS idx_users_stripe_customer_id ON users(stripe_customer_id);

backend/infra/migrations/008_add_min_max_to_alert_rules.sql

@@ -0,0 +1,6 @@
+ALTER TABLE alert_rules ADD COLUMN minimum DECIMAL(20, 6);
+ALTER TABLE alert_rules ADD COLUMN maximum DECIMAL(20, 6);
+
+ALTER TABLE alert_rules ADD CONSTRAINT non_negative_minimum CHECK (minimum IS NULL OR minimum >= 0);
+ALTER TABLE alert_rules ADD CONSTRAINT non_negative_maximum CHECK (maximum IS NULL OR maximum >= 0);
+ALTER TABLE alert_rules ADD CONSTRAINT min_lte_max CHECK (minimum IS NULL OR maximum IS NULL OR minimum <= maximum);

backend/infra/migrations/009_add_subscription_tier.sql

@@ -0,0 +1,8 @@
+ALTER TABLE users ADD COLUMN IF NOT EXISTS subscription_tier VARCHAR(20) DEFAULT 'free';
+
+-- Existing active/trialing subscribers were on the single paid plan,
+-- which is now the "premium" tier. Backfill them so they aren't downgraded.
+UPDATE users
+SET subscription_tier = 'premium'
+WHERE subscription_status IN ('active', 'trialing')
+  AND stripe_subscription_id IS NOT NULL;

backend/infra/schema.sql

@@ -11,6 +11,11 @@ CREATE TABLE users (
   firebase_uid VARCHAR(128) NOT NULL UNIQUE,
   email VARCHAR(255) NOT NULL,
   display_name VARCHAR(255),
+  stripe_customer_id VARCHAR(255),
+  stripe_subscription_id VARCHAR(255),
+  subscription_status VARCHAR(50) DEFAULT 'none',
+  subscription_tier VARCHAR(20) DEFAULT 'free',
+  subscription_created_at TIMESTAMP,
   created_at TIMESTAMP DEFAULT NOW(),
   updated_at TIMESTAMP DEFAULT NOW()
 );
@@ -31,6 +36,8 @@ CREATE TABLE alert_rules (
   address_id INTEGER NOT NULL REFERENCES addresses(id) ON DELETE CASCADE,
   type VARCHAR(50) NOT NULL,           -- 'incoming_tx', 'outgoing_tx', 'large_transfer', 'balance_below'
   threshold DECIMAL(20, 6),            -- ETH amount threshold (nullable for tx types that don't need it)
+  minimum DECIMAL(20, 6),              -- Optional min amount filter for incoming/outgoing alerts
+  maximum DECIMAL(20, 6),              -- Optional max amount filter for incoming/outgoing alerts
   enabled BOOLEAN DEFAULT TRUE,
   created_at TIMESTAMP DEFAULT NOW(),
 
@@ -40,7 +47,11 @@ CREATE TABLE alert_rules (
 
   CONSTRAINT positive_threshold CHECK (
     threshold IS NULL OR threshold > 0
-  )
+  ),
+
+  CONSTRAINT non_negative_minimum CHECK (minimum IS NULL OR minimum >= 0),
+  CONSTRAINT non_negative_maximum CHECK (maximum IS NULL OR maximum >= 0),
+  CONSTRAINT min_lte_max CHECK (minimum IS NULL OR maximum IS NULL OR minimum <= maximum)
 );
 
 
@@ -73,6 +84,7 @@ CREATE TABLE user_notification_configs (
 
 -- Create indexes for common queries
 CREATE INDEX idx_users_firebase_uid ON users(firebase_uid);
+CREATE INDEX idx_users_stripe_customer_id ON users(stripe_customer_id);
 CREATE INDEX idx_addresses_user_id ON addresses(user_id);
 CREATE INDEX idx_alert_rules_address_id ON alert_rules(address_id);
 CREATE INDEX idx_alert_rules_enabled ON alert_rules(enabled);

backend/internal/config/config.go

@@ -32,6 +32,12 @@ type Config struct {
 	ResendAPIKey         string
 	EmailFrom            string
 	DigestIntervalHours  int
+	StripeSecretKey        string
+	StripeWebhookSecret    string
+	StripePriceIDPremium   string
+	StripePriceIDPro       string
+	StripePublishableKey   string
+	FrontendURL            string
 }
 
 // Load reads configuration from environment variables and returns a Config.
@@ -51,7 +57,13 @@ func Load() (*Config, error) {
 		NodeEnv:           getEnv("NODE_ENV", "development"),
 		ResendAPIKey:        os.Getenv("RESEND_API_KEY"),
 		EmailFrom:           getEnv("EMAIL_FROM", "Koin Ping <alerts@koinping.com>"),
-		DigestIntervalHours: getEnvInt("DIGEST_INTERVAL_HOURS", defaultDigestIntervalHours),
+		DigestIntervalHours:  getEnvInt("DIGEST_INTERVAL_HOURS", defaultDigestIntervalHours),
+		StripeSecretKey:        os.Getenv("STRIPE_SECRET_KEY"),
+		StripeWebhookSecret:    os.Getenv("STRIPE_WEBHOOK_SECRET"),
+		StripePriceIDPremium:   os.Getenv("STRIPE_PRICE_ID_PREMIUM"),
+		StripePriceIDPro:       os.Getenv("STRIPE_PRICE_ID_PRO"),
+		StripePublishableKey:   os.Getenv("STRIPE_PUBLISHABLE_KEY"),
+		FrontendURL:          getEnv("FRONTEND_URL", "http://localhost:3000"),
 	}
 
 	if cfg.PollIntervalMS < minPollIntervalMS {
@@ -82,6 +94,19 @@ func (c *Config) DSN() string {
 	)
 }
 
+// TierForPriceID maps a Stripe price ID back to the corresponding
+// subscription tier. Returns empty string if the price is unrecognised.
+func (c *Config) TierForPriceID(priceID string) string {
+	switch priceID {
+	case c.StripePriceIDPremium:
+		return "premium"
+	case c.StripePriceIDPro:
+		return "pro"
+	default:
+		return ""
+	}
+}
+
 func getEnv(key, fallback string) string {
 	if v := os.Getenv(key); v != "" {
 		return v

backend/internal/config/config_test.go

@@ -0,0 +1,28 @@
+package config
+
+import "testing"
+
+func TestTierForPriceID(t *testing.T) {
+	t.Parallel()
+
+	cfg := &Config{
+		StripePriceIDPremium: "price_premium_123",
+		StripePriceIDPro:     "price_pro_456",
+	}
+
+	tests := []struct {
+		priceID string
+		want    string
+	}{
+		{"price_premium_123", "premium"},
+		{"price_pro_456", "pro"},
+		{"price_unknown", ""},
+		{"", ""},
+	}
+
+	for _, tt := range tests {
+		if got := cfg.TierForPriceID(tt.priceID); got != tt.want {
+			t.Errorf("TierForPriceID(%q) = %q, want %q", tt.priceID, got, tt.want)
+		}
+	}
+}

backend/internal/domain/types.go

@@ -2,13 +2,77 @@ package domain
 
 import "time"
 
+type SubscriptionTier string
+
+const (
+	TierFree    SubscriptionTier = "free"
+	TierPremium SubscriptionTier = "premium"
+	TierPro     SubscriptionTier = "pro"
+)
+
+func IsValidTier(t string) bool {
+	switch SubscriptionTier(t) {
+	case TierFree, TierPremium, TierPro:
+		return true
+	}
+	return false
+}
+
+const unlimitedLimit = -1
+
+type TierLimits struct {
+	MaxAddresses    int      `json:"max_addresses"`
+	MaxAlertTypes   int      `json:"max_alert_types"`
+	AllowedChannels []string `json:"allowed_channels"`
+}
+
+func GetTierLimits(tier SubscriptionTier) TierLimits {
+	switch tier {
+	case TierPremium:
+		return TierLimits{
+			MaxAddresses:    3,
+			MaxAlertTypes:   2,
+			AllowedChannels: []string{"email", "discord", "telegram"},
+		}
+	case TierPro:
+		return TierLimits{
+			MaxAddresses:    unlimitedLimit,
+			MaxAlertTypes:   unlimitedLimit,
+			AllowedChannels: []string{"email", "discord", "telegram", "slack"},
+		}
+	default:
+		return TierLimits{
+			MaxAddresses:    1,
+			MaxAlertTypes:   1,
+			AllowedChannels: []string{"email"},
+		}
+	}
+}
+
+func (l TierLimits) IsUnlimitedAddresses() bool  { return l.MaxAddresses == unlimitedLimit }
+func (l TierLimits) IsUnlimitedAlertTypes() bool  { return l.MaxAlertTypes == unlimitedLimit }
+
+func (l TierLimits) ChannelAllowed(channel string) bool {
+	for _, c := range l.AllowedChannels {
+		if c == channel {
+			return true
+		}
+	}
+	return false
+}
+
 type User struct {
-	ID          string    `json:"id"`
-	FirebaseUID string    `json:"-"`
-	Email       string    `json:"email"`
-	DisplayName *string   `json:"display_name"` //nolint:tagliatelle
-	CreatedAt   time.Time `json:"created_at"`   //nolint:tagliatelle
-	UpdatedAt   time.Time `json:"updated_at"`   //nolint:tagliatelle
+	ID                    string           `json:"id"`
+	FirebaseUID           string           `json:"-"`
+	Email                 string           `json:"email"`
+	DisplayName           *string          `json:"display_name"`           //nolint:tagliatelle
+	StripeCustomerID      *string          `json:"-"`
+	StripeSubscriptionID  *string          `json:"-"`
+	SubscriptionStatus    string           `json:"subscription_status"`    //nolint:tagliatelle
+	SubscriptionTier      SubscriptionTier `json:"subscription_tier"`      //nolint:tagliatelle
+	SubscriptionCreatedAt *time.Time       `json:"subscription_created_at,omitempty"` //nolint:tagliatelle
+	CreatedAt             time.Time        `json:"created_at"`             //nolint:tagliatelle
+	UpdatedAt             time.Time        `json:"updated_at"`             //nolint:tagliatelle
 }
 
 type Address struct {
@@ -43,7 +107,7 @@ var ThresholdRequiredTypes = []AlertType{ //nolint:gochecknoglobals
 	AlertBalanceBelow,
 }
 
-// IsValidAlertType returns true if the given string matches a known AlertType.
+// returns true if the given string matches a known AlertType.
 func IsValidAlertType(t string) bool {
 	for _, v := range ValidAlertTypes {
 		if string(v) == t {
@@ -54,7 +118,6 @@ func IsValidAlertType(t string) bool {
 	return false
 }
 
-// IsThresholdRequired returns true if the given AlertType requires a threshold.
 func IsThresholdRequired(t AlertType) bool {
 	for _, v := range ThresholdRequiredTypes {
 		if v == t {
@@ -70,6 +133,8 @@ type AlertRule struct {
 	AddressID int       `json:"address_id"` //nolint:tagliatelle
 	Type      AlertType `json:"type"`
 	Threshold *float64  `json:"threshold"`
+	Minimum   *float64  `json:"minimum"`
+	Maximum   *float64  `json:"maximum"`
 	Enabled   bool      `json:"enabled"`
 	CreatedAt time.Time `json:"created_at"` //nolint:tagliatelle
 }
@@ -89,7 +154,6 @@ type AddressCheckpoint struct {
 	LastCheckedAt    time.Time `json:"last_checked_at"`    //nolint:tagliatelle
 }
 
-// CheckpointDetail combines checkpoint and address info for reporting.
 type CheckpointDetail struct {
 	AddressID        int       `json:"address_id"`         //nolint:tagliatelle
 	Address          string    `json:"address"`
@@ -98,7 +162,7 @@ type CheckpointDetail struct {
 	LastCheckedAt    time.Time `json:"last_checked_at"`    //nolint:tagliatelle
 }
 
-// NotificationConfig holds a user's notification preferences.
+//  holds a user's notification preferences.
 type NotificationConfig struct {
 	UserID              string     `json:"user_id"`              //nolint:tagliatelle
 	DiscordWebhookURL   *string    `json:"discord_webhook_url"`  //nolint:tagliatelle
@@ -127,14 +191,12 @@ type NormalizedTx struct {
 	TokenValue    *string `json:"token_value,omitempty"`    //nolint:tagliatelle
 }
 
-// IsTokenTransfer returns true if this transaction represents an ERC-20 token transfer.
 func (tx NormalizedTx) IsTokenTransfer() bool {
 	return tx.TokenContract != nil
 }
 
 type Direction string
 
-// String implements fmt.Stringer.
 func (d Direction) String() string { return string(d) }
 
 const (

backend/internal/domain/types_test.go

@@ -0,0 +1,104 @@
+package domain
+
+import "testing"
+
+func TestIsValidTier(t *testing.T) {
+	t.Parallel()
+
+	valid := []string{"free", "premium", "pro"}
+	for _, tier := range valid {
+		if !IsValidTier(tier) {
+			t.Errorf("expected %q to be valid", tier)
+		}
+	}
+
+	invalid := []string{"", "basic", "enterprise", "FREE", "Pro"}
+	for _, tier := range invalid {
+		if IsValidTier(tier) {
+			t.Errorf("expected %q to be invalid", tier)
+		}
+	}
+}
+
+func TestGetTierLimits_Free(t *testing.T) {
+	t.Parallel()
+
+	limits := GetTierLimits(TierFree)
+	if limits.MaxAddresses != 1 {
+		t.Errorf("free MaxAddresses = %d, want 1", limits.MaxAddresses)
+	}
+	if limits.MaxAlertTypes != 1 {
+		t.Errorf("free MaxAlertTypes = %d, want 1", limits.MaxAlertTypes)
+	}
+	if len(limits.AllowedChannels) != 1 || limits.AllowedChannels[0] != "email" {
+		t.Errorf("free AllowedChannels = %v, want [email]", limits.AllowedChannels)
+	}
+	if limits.IsUnlimitedAddresses() {
+		t.Error("free should not have unlimited addresses")
+	}
+	if limits.IsUnlimitedAlertTypes() {
+		t.Error("free should not have unlimited alert types")
+	}
+}
+
+func TestGetTierLimits_Premium(t *testing.T) {
+	t.Parallel()
+
+	limits := GetTierLimits(TierPremium)
+	if limits.MaxAddresses != 3 {
+		t.Errorf("premium MaxAddresses = %d, want 3", limits.MaxAddresses)
+	}
+	if limits.MaxAlertTypes != 2 {
+		t.Errorf("premium MaxAlertTypes = %d, want 2", limits.MaxAlertTypes)
+	}
+	if !limits.ChannelAllowed("email") {
+		t.Error("premium should allow email")
+	}
+	if !limits.ChannelAllowed("discord") {
+		t.Error("premium should allow discord")
+	}
+	if !limits.ChannelAllowed("telegram") {
+		t.Error("premium should allow telegram")
+	}
+	if limits.ChannelAllowed("slack") {
+		t.Error("premium should NOT allow slack")
+	}
+}
+
+func TestGetTierLimits_Pro(t *testing.T) {
+	t.Parallel()
+
+	limits := GetTierLimits(TierPro)
+	if !limits.IsUnlimitedAddresses() {
+		t.Error("pro should have unlimited addresses")
+	}
+	if !limits.IsUnlimitedAlertTypes() {
+		t.Error("pro should have unlimited alert types")
+	}
+	for _, ch := range []string{"email", "discord", "telegram", "slack"} {
+		if !limits.ChannelAllowed(ch) {
+			t.Errorf("pro should allow %s", ch)
+		}
+	}
+}
+
+func TestGetTierLimits_Unknown(t *testing.T) {
+	t.Parallel()
+
+	limits := GetTierLimits(SubscriptionTier("unknown"))
+	if limits.MaxAddresses != 1 {
+		t.Errorf("unknown tier should default to free limits, got MaxAddresses=%d", limits.MaxAddresses)
+	}
+}
+
+func TestChannelAllowed_NotInList(t *testing.T) {
+	t.Parallel()
+
+	limits := GetTierLimits(TierFree)
+	if limits.ChannelAllowed("discord") {
+		t.Error("free should not allow discord")
+	}
+	if limits.ChannelAllowed("nonexistent") {
+		t.Error("nonexistent channel should not be allowed")
+	}
+}

backend/internal/handlers/account.go

@@ -0,0 +1,88 @@
+package handlers
+
+import (
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/kjannette/koin-ping/backend/internal/config"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/middleware"
+	"github.com/kjannette/koin-ping/backend/internal/models"
+)
+
+type AccountHandler struct {
+	users     *models.UserModel
+	addresses *models.AddressModel
+	cfg       *config.Config
+}
+
+func NewAccountHandler(users *models.UserModel, addresses *models.AddressModel, cfg *config.Config) *AccountHandler {
+	return &AccountHandler{users: users, addresses: addresses, cfg: cfg}
+}
+
+type accountResponse struct {
+	UserID             string            `json:"user_id"`
+	Email              string            `json:"email"`
+	UserName           string            `json:"user_name"`
+	SubscriptionStatus string            `json:"subscription_status"`
+	SubscriptionTier   string            `json:"subscription_tier"`
+	SubscriptionPlan   string            `json:"subscription_plan"`
+	TierLimits         domain.TierLimits `json:"tier_limits"`
+	AddressCount       int               `json:"address_count"`
+	MemberSince        *string           `json:"member_since,omitempty"`
+	NextBillingDate    *string           `json:"next_billing_date,omitempty"`
+	CancelAtPeriodEnd  bool              `json:"cancel_at_period_end"`
+	PeriodEndDate      *string           `json:"period_end_date,omitempty"`
+}
+
+var tierPlanLabels = map[domain.SubscriptionTier]string{ //nolint:gochecknoglobals
+	domain.TierFree:    "Free Trial",
+	domain.TierPremium: "Premium / $1.99 mo",
+	domain.TierPro:     "Pro / $11.99 mo",
+}
+
+func (h *AccountHandler) GetAccount(w http.ResponseWriter, r *http.Request) {
+	userID := middleware.GetUserID(r.Context())
+	email := middleware.GetUserEmail(r.Context())
+
+	user, err := h.users.GetByID(r.Context(), userID)
+	if err != nil || user == nil {
+		log.Printf("Account: failed to get user %s: %v", userID, err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to load user")
+		return
+	}
+
+	addrCount, err := h.addresses.CountByUser(r.Context(), userID)
+	if err != nil {
+		log.Printf("Account: failed to count addresses for %s: %v", userID, err)
+		addrCount = 0
+	}
+
+	planLabel := tierPlanLabels[user.SubscriptionTier]
+	if planLabel == "" {
+		planLabel = "Free Trial"
+	}
+
+	resp := accountResponse{
+		UserID:             user.ID,
+		Email:              email,
+		UserName:           email,
+		SubscriptionStatus: user.SubscriptionStatus,
+		SubscriptionTier:   string(user.SubscriptionTier),
+		SubscriptionPlan:   planLabel,
+		TierLimits:         domain.GetTierLimits(user.SubscriptionTier),
+		AddressCount:       addrCount,
+	}
+
+	if user.SubscriptionCreatedAt != nil {
+		t := user.SubscriptionCreatedAt.Format(time.DateOnly)
+		resp.MemberSince = &t
+	}
+
+	resp.NextBillingDate = nil
+	resp.CancelAtPeriodEnd = false
+	resp.PeriodEndDate = nil
+
+	writeJSON(w, http.StatusOK, resp)
+}

backend/internal/handlers/address.go

@@ -3,24 +3,26 @@ package handlers
 
 import (
 	"encoding/json"
+	"fmt"
 	"log"
 	"net/http"
 	"regexp"
 	"strings"
 
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
-	"github.com/kjannette/koin-ping/backend-go/internal/middleware"
-	"github.com/kjannette/koin-ping/backend-go/internal/models"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/middleware"
+	"github.com/kjannette/koin-ping/backend/internal/models"
 )
 
 var ethAddressRe = regexp.MustCompile(`^0x[a-fA-F0-9]{40}$`)
 
 type AddressHandler struct {
 	addresses *models.AddressModel
+	users     *models.UserModel
 }
 
-func NewAddressHandler(addresses *models.AddressModel) *AddressHandler {
-	return &AddressHandler{addresses: addresses}
+func NewAddressHandler(addresses *models.AddressModel, users *models.UserModel) *AddressHandler {
+	return &AddressHandler{addresses: addresses, users: users}
 }
 
 func (h *AddressHandler) Create(w http.ResponseWriter, r *http.Request) {
@@ -49,6 +51,28 @@ func (h *AddressHandler) Create(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	user, err := h.users.GetByID(r.Context(), userID)
+	if err != nil || user == nil {
+		log.Printf("Failed to get user %s for tier check: %v", userID, err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to verify account")
+		return
+	}
+
+	limits := domain.GetTierLimits(user.SubscriptionTier)
+	if !limits.IsUnlimitedAddresses() {
+		count, err := h.addresses.CountByUser(r.Context(), userID)
+		if err != nil {
+			log.Printf("Failed to count addresses for user %s: %v", userID, err)
+			writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to create address")
+			return
+		}
+		if count >= limits.MaxAddresses {
+			writeError(w, http.StatusForbidden, "TIER_LIMIT_REACHED",
+				fmt.Sprintf("Your %s plan allows %d address(es). Upgrade to track more.", user.SubscriptionTier, limits.MaxAddresses))
+			return
+		}
+	}
+
 	log.Printf("User %s creating address: %s", userID, body.Address)
 
 	addr, err := h.addresses.Create(r.Context(), userID, body.Address, body.Label)

backend/internal/handlers/alert_event.go

@@ -5,9 +5,9 @@ import (
 	"net/http"
 	"strconv"
 
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
-	"github.com/kjannette/koin-ping/backend-go/internal/middleware"
-	"github.com/kjannette/koin-ping/backend-go/internal/models"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/middleware"
+	"github.com/kjannette/koin-ping/backend/internal/models"
 )
 
 // AlertEventHandler handles HTTP requests for alert event history.

backend/internal/handlers/alert_rule.go

@@ -9,9 +9,9 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
-	"github.com/kjannette/koin-ping/backend-go/internal/middleware"
-	"github.com/kjannette/koin-ping/backend-go/internal/models"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/middleware"
+	"github.com/kjannette/koin-ping/backend/internal/models"
 )
 
 var errThresholdFormat = errors.New("unsupported threshold format")
@@ -19,10 +19,11 @@ var errThresholdFormat = errors.New("unsupported threshold format")
 type AlertRuleHandler struct {
 	alertRules *models.AlertRuleModel
 	addresses  *models.AddressModel
+	users      *models.UserModel
 }
 
-func NewAlertRuleHandler(alertRules *models.AlertRuleModel, addresses *models.AddressModel) *AlertRuleHandler {
-	return &AlertRuleHandler{alertRules: alertRules, addresses: addresses}
+func NewAlertRuleHandler(alertRules *models.AlertRuleModel, addresses *models.AddressModel, users *models.UserModel) *AlertRuleHandler {
+	return &AlertRuleHandler{alertRules: alertRules, addresses: addresses, users: users}
 }
 
 func (h *AlertRuleHandler) Create(w http.ResponseWriter, r *http.Request) {
@@ -37,6 +38,8 @@ func (h *AlertRuleHandler) Create(w http.ResponseWriter, r *http.Request) {
 	var body struct {
 		Type      string          `json:"type"`
 		Threshold json.RawMessage `json:"threshold"`
+		Minimum   json.RawMessage `json:"minimum"`
+		Maximum   json.RawMessage `json:"maximum"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
 		log.Printf("Failed to decode alert request body: %v", err)
@@ -53,6 +56,40 @@ func (h *AlertRuleHandler) Create(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	minimum, err := parseThreshold(body.Minimum)
+	if err != nil {
+		log.Printf("Failed to parse minimum: %v", err)
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "minimum must be a valid number")
+
+		return
+	}
+
+	maximum, err := parseThreshold(body.Maximum)
+	if err != nil {
+		log.Printf("Failed to parse maximum: %v", err)
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "maximum must be a valid number")
+
+		return
+	}
+
+	if minimum != nil && *minimum < 0 {
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "minimum must be non-negative")
+
+		return
+	}
+
+	if maximum != nil && *maximum < 0 {
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "maximum must be non-negative")
+
+		return
+	}
+
+	if minimum != nil && maximum != nil && *minimum > *maximum {
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "minimum must not exceed maximum")
+
+		return
+	}
+
 	log.Printf("User %s creating alert: type=%s, addressID=%d", userID, body.Type, addressID)
 
 	if body.Type == "" {
@@ -96,7 +133,29 @@ func (h *AlertRuleHandler) Create(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	newAlert, err := h.alertRules.Create(r.Context(), addressID, alertType, threshold)
+	user, userErr := h.users.GetByID(r.Context(), userID)
+	if userErr != nil || user == nil {
+		log.Printf("Failed to get user %s for tier check: %v", userID, userErr)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to verify account")
+		return
+	}
+
+	limits := domain.GetTierLimits(user.SubscriptionTier)
+	if !limits.IsUnlimitedAlertTypes() {
+		typeCount, countErr := h.alertRules.CountDistinctTypesByAddress(r.Context(), addressID)
+		if countErr != nil {
+			log.Printf("Failed to count alert types for address %d: %v", addressID, countErr)
+			writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to create alert rule")
+			return
+		}
+		if typeCount >= limits.MaxAlertTypes {
+			writeError(w, http.StatusForbidden, "TIER_LIMIT_REACHED",
+				fmt.Sprintf("Your %s plan allows %d alert type(s) per address. Upgrade for more.", user.SubscriptionTier, limits.MaxAlertTypes))
+			return
+		}
+	}
+
+	newAlert, err := h.alertRules.Create(r.Context(), addressID, alertType, threshold, minimum, maximum)
 	if err != nil {
 		log.Printf("Error creating alert rule: %v", err)
 		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to create alert rule")
@@ -182,7 +241,7 @@ func (h *AlertRuleHandler) ListByAddress(w http.ResponseWriter, r *http.Request)
 	writeJSON(w, http.StatusOK, alerts)
 }
 
-// UpdateStatus handles PATCH requests to enable or disable an alert rule.
+// UpdateStatus handles PATCH requests to enable/disable an alert rule and/or update min/max thresholds.
 func (h *AlertRuleHandler) UpdateStatus(w http.ResponseWriter, r *http.Request) {
 	userID := middleware.GetUserID(r.Context())
 	alertID, ok := parseIntParam(r.PathValue("alertId"))
@@ -193,7 +252,10 @@ func (h *AlertRuleHandler) UpdateStatus(w http.ResponseWriter, r *http.Request)
 	}
 
 	var body struct {
-		Enabled *bool `json:"enabled"`
+		Enabled        *bool           `json:"enabled"`
+		Minimum        json.RawMessage `json:"minimum"`
+		Maximum        json.RawMessage `json:"maximum"`
+		UpdateMinMax   bool            `json:"update_min_max"`   //nolint:tagliatelle
 	}
 	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
 		log.Printf("Failed to decode update request body: %v", err)
@@ -204,8 +266,8 @@ func (h *AlertRuleHandler) UpdateStatus(w http.ResponseWriter, r *http.Request)
 
 	log.Printf("User %s updating alert ID: %d", userID, alertID)
 
-	if body.Enabled == nil {
-		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "enabled must be a boolean value")
+	if body.Enabled == nil && !body.UpdateMinMax {
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "must provide enabled (boolean) or update_min_max with minimum/maximum values")
 
 		return
 	}
@@ -224,15 +286,64 @@ func (h *AlertRuleHandler) UpdateStatus(w http.ResponseWriter, r *http.Request)
 		return
 	}
 
-	updated, err := h.alertRules.UpdateEnabled(r.Context(), alertID, *body.Enabled)
-	if err != nil {
-		log.Printf("Error updating alert: %v", err)
-		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to update alert")
+	var updated *domain.AlertRule
 
-		return
+	if body.UpdateMinMax {
+		minimum, parseErr := parseThreshold(body.Minimum)
+		if parseErr != nil {
+			writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "minimum must be a valid number")
+
+			return
+		}
+
+		maximum, parseErr := parseThreshold(body.Maximum)
+		if parseErr != nil {
+			writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "maximum must be a valid number")
+
+			return
+		}
+
+		if minimum != nil && *minimum < 0 {
+			writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "minimum must be non-negative")
+
+			return
+		}
+
+		if maximum != nil && *maximum < 0 {
+			writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "maximum must be non-negative")
+
+			return
+		}
+
+		if minimum != nil && maximum != nil && *minimum > *maximum {
+			writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "minimum must not exceed maximum")
+
+			return
+		}
+
+		updated, err = h.alertRules.UpdateThresholds(r.Context(), alertID, minimum, maximum)
+		if err != nil {
+			log.Printf("Error updating alert thresholds: %v", err)
+			writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to update alert")
+
+			return
+		}
+
+		log.Printf("Alert %d thresholds updated: min=%v, max=%v", alertID, minimum, maximum)
+	}
+
+	if body.Enabled != nil {
+		updated, err = h.alertRules.UpdateEnabled(r.Context(), alertID, *body.Enabled)
+		if err != nil {
+			log.Printf("Error updating alert: %v", err)
+			writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to update alert")
+
+			return
+		}
+
+		log.Printf("Alert %d updated: enabled=%v", alertID, *body.Enabled)
 	}
 
-	log.Printf("Alert %d updated: enabled=%v", alertID, *body.Enabled)
 	writeJSON(w, http.StatusOK, updated)
 }
 

backend/internal/handlers/email_digest.go

@@ -4,9 +4,9 @@ import (
 	"log"
 	"net/http"
 
-	"github.com/kjannette/koin-ping/backend-go/internal/middleware"
-	"github.com/kjannette/koin-ping/backend-go/internal/models"
-	"github.com/kjannette/koin-ping/backend-go/internal/services"
+	"github.com/kjannette/koin-ping/backend/internal/middleware"
+	"github.com/kjannette/koin-ping/backend/internal/models"
+	"github.com/kjannette/koin-ping/backend/internal/services"
 )
 
 type EmailDigestHandler struct {

backend/internal/handlers/notification_config.go

@@ -7,22 +7,23 @@ import (
 	"regexp"
 	"strings"
 
-	"github.com/kjannette/koin-ping/backend-go/internal/config"
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
-	"github.com/kjannette/koin-ping/backend-go/internal/middleware"
-	"github.com/kjannette/koin-ping/backend-go/internal/models"
-	"github.com/kjannette/koin-ping/backend-go/internal/notifications"
+	"github.com/kjannette/koin-ping/backend/internal/config"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/middleware"
+	"github.com/kjannette/koin-ping/backend/internal/models"
+	"github.com/kjannette/koin-ping/backend/internal/notifications"
 )
 
 var emailRe = regexp.MustCompile(`^[^\s@]+@[^\s@]+\.[^\s@]+$`)
 
 type NotificationConfigHandler struct {
 	configs *models.NotificationConfigModel
+	users   *models.UserModel
 	cfg     *config.Config
 }
 
-func NewNotificationConfigHandler(configs *models.NotificationConfigModel, cfg *config.Config) *NotificationConfigHandler {
-	return &NotificationConfigHandler{configs: configs, cfg: cfg}
+func NewNotificationConfigHandler(configs *models.NotificationConfigModel, users *models.UserModel, cfg *config.Config) *NotificationConfigHandler {
+	return &NotificationConfigHandler{configs: configs, users: users, cfg: cfg}
 }
 
 func (h *NotificationConfigHandler) GetConfig(w http.ResponseWriter, r *http.Request) {
@@ -95,6 +96,26 @@ func (h *NotificationConfigHandler) UpdateConfig(w http.ResponseWriter, r *http.
 		return
 	}
 
+	user, userErr := h.users.GetByID(r.Context(), userID)
+	if userErr != nil || user == nil {
+		log.Printf("Failed to get user %s for tier check: %v", userID, userErr)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to verify account")
+		return
+	}
+
+	limits := domain.GetTierLimits(user.SubscriptionTier)
+
+	if !limits.ChannelAllowed("discord") {
+		body.DiscordWebhookURL = nil
+	}
+	if !limits.ChannelAllowed("telegram") {
+		body.TelegramBotToken = nil
+		body.TelegramChatID = nil
+	}
+	if !limits.ChannelAllowed("slack") {
+		body.SlackWebhookURL = nil
+	}
+
 	enabled := true
 	if body.NotificationEnabled != nil {
 		enabled = *body.NotificationEnabled

backend/internal/handlers/status.go

@@ -5,7 +5,7 @@ import (
 	"net/http"
 	"time"
 
-	"github.com/kjannette/koin-ping/backend-go/internal/models"
+	"github.com/kjannette/koin-ping/backend/internal/models"
 )
 
 // StatusHandler handles the system status endpoint.

backend/internal/handlers/stripe.go

@@ -0,0 +1,429 @@
+package handlers
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+
+	"github.com/stripe/stripe-go/v82"
+	portalsession "github.com/stripe/stripe-go/v82/billingportal/session"
+	checkoutsession "github.com/stripe/stripe-go/v82/checkout/session"
+	"github.com/stripe/stripe-go/v82/webhook"
+
+	"github.com/kjannette/koin-ping/backend/internal/config"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/middleware"
+	"github.com/kjannette/koin-ping/backend/internal/models"
+)
+
+const webhookMaxBodyBytes = 65536
+
+type StripeHandler struct {
+	users *models.UserModel
+	cfg   *config.Config
+}
+
+func NewStripeHandler(users *models.UserModel, cfg *config.Config) *StripeHandler {
+	stripe.Key = cfg.StripeSecretKey
+	return &StripeHandler{users: users, cfg: cfg}
+}
+
+func (h *StripeHandler) priceIDForTier(tier domain.SubscriptionTier) (string, error) {
+	switch tier {
+	case domain.TierPremium:
+		return h.cfg.StripePriceIDPremium, nil
+	case domain.TierPro:
+		return h.cfg.StripePriceIDPro, nil
+	default:
+		return "", fmt.Errorf("no Stripe price for tier %q", tier) //nolint:err113
+	}
+}
+
+// CreateCheckoutSession creates a Stripe Checkout session for the selected tier.
+func (h *StripeHandler) CreateCheckoutSession(w http.ResponseWriter, r *http.Request) {
+	userID := middleware.GetUserID(r.Context())
+
+	var body struct {
+		Tier string `json:"tier"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+		writeError(w, http.StatusBadRequest, "BAD_REQUEST", "Invalid request body")
+		return
+	}
+
+	if body.Tier == "" {
+		body.Tier = "premium"
+	}
+
+	tier := domain.SubscriptionTier(body.Tier)
+	if tier != domain.TierPremium && tier != domain.TierPro {
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "Tier must be 'premium' or 'pro'")
+		return
+	}
+
+	priceID, err := h.priceIDForTier(tier)
+	if err != nil {
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", err.Error())
+		return
+	}
+
+	user, err := h.users.GetByID(r.Context(), userID)
+	if err != nil || user == nil {
+		log.Printf("Failed to get user %s: %v", userID, err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to load user")
+		return
+	}
+
+	params := &stripe.CheckoutSessionParams{
+		Mode: stripe.String(string(stripe.CheckoutSessionModeSubscription)),
+		LineItems: []*stripe.CheckoutSessionLineItemParams{
+			{
+				Price:    stripe.String(priceID),
+				Quantity: stripe.Int64(1),
+			},
+		},
+		SuccessURL:        stripe.String(h.cfg.FrontendURL + "/subscribe?payment=success&session_id={CHECKOUT_SESSION_ID}"),
+		CancelURL:         stripe.String(h.cfg.FrontendURL + "/subscribe?payment=cancelled"),
+		ClientReferenceID: stripe.String(userID),
+		CustomerEmail:     stripe.String(user.Email),
+	}
+
+	params.AddMetadata("tier", string(tier))
+
+	if user.StripeCustomerID != nil && *user.StripeCustomerID != "" {
+		params.Customer = user.StripeCustomerID
+		params.CustomerEmail = nil
+	}
+
+	s, err := checkoutsession.New(params)
+	if err != nil {
+		log.Printf("Failed to create Stripe checkout session: %v", err)
+		writeError(w, http.StatusInternalServerError, "STRIPE_ERROR", "Failed to create checkout session")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]string{"url": s.URL})
+}
+
+// GetSubscriptionStatus returns the current user's subscription state.
+func (h *StripeHandler) GetSubscriptionStatus(w http.ResponseWriter, r *http.Request) {
+	userID := middleware.GetUserID(r.Context())
+
+	user, err := h.users.GetByID(r.Context(), userID)
+	if err != nil || user == nil {
+		log.Printf("Failed to get user %s: %v", userID, err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to load user")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"subscription_status": user.SubscriptionStatus,
+		"subscription_tier":   user.SubscriptionTier,
+		"subscription_created_at": user.SubscriptionCreatedAt,
+	})
+}
+
+// VerifyCheckoutSession retrieves a completed checkout session from Stripe,
+// confirms payment, and activates the user's subscription in the database.
+func (h *StripeHandler) VerifyCheckoutSession(w http.ResponseWriter, r *http.Request) {
+	userID := middleware.GetUserID(r.Context())
+
+	var body struct {
+		SessionID string `json:"session_id"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil || body.SessionID == "" {
+		writeError(w, http.StatusBadRequest, "BAD_REQUEST", "Missing session_id")
+		return
+	}
+
+	s, err := checkoutsession.Get(body.SessionID, nil)
+	if err != nil {
+		log.Printf("Failed to retrieve checkout session %s: %v", body.SessionID, err)
+		writeError(w, http.StatusBadRequest, "STRIPE_ERROR", "Invalid checkout session")
+		return
+	}
+
+	if s.ClientReferenceID != "" && s.ClientReferenceID != userID {
+		writeError(w, http.StatusForbidden, "FORBIDDEN", "Session does not belong to this user")
+		return
+	}
+
+	if s.PaymentStatus != stripe.CheckoutSessionPaymentStatusPaid {
+		writeError(w, http.StatusBadRequest, "PAYMENT_INCOMPLETE", "Payment has not been completed")
+		return
+	}
+
+	tier := domain.TierPremium
+	if t, ok := s.Metadata["tier"]; ok && domain.IsValidTier(t) {
+		tier = domain.SubscriptionTier(t)
+	}
+
+	customerID := ""
+	if s.Customer != nil {
+		customerID = s.Customer.ID
+	}
+	subscriptionID := ""
+	if s.Subscription != nil {
+		subscriptionID = s.Subscription.ID
+	}
+
+	if customerID != "" {
+		if err := h.users.UpdateStripeCustomer(r.Context(), userID, customerID); err != nil {
+			log.Printf("VerifyCheckout: failed to save customer ID: %v", err)
+		}
+	}
+	if subscriptionID != "" && customerID != "" {
+		if err := h.users.ActivateSubscription(r.Context(), customerID, subscriptionID, "active", tier); err != nil {
+			log.Printf("VerifyCheckout: failed to activate subscription: %v", err)
+		}
+	}
+
+	log.Printf("Checkout verified for user %s, customer %s, subscription %s, tier %s", userID, customerID, subscriptionID, tier)
+	writeJSON(w, http.StatusOK, map[string]string{
+		"subscription_status": "active",
+		"subscription_tier":   string(tier),
+	})
+}
+
+// ActivateFreeTier sets the user to the free tier without Stripe involvement.
+func (h *StripeHandler) ActivateFreeTier(w http.ResponseWriter, r *http.Request) {
+	userID := middleware.GetUserID(r.Context())
+
+	if err := h.users.ActivateFreeTier(r.Context(), userID); err != nil {
+		log.Printf("ActivateFreeTier: failed for user %s: %v", userID, err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to activate free tier")
+		return
+	}
+
+	log.Printf("Free tier activated for user %s", userID)
+	writeJSON(w, http.StatusOK, map[string]string{
+		"subscription_status": "active",
+		"subscription_tier":   "free",
+	})
+}
+
+// CreateOnboardingCheckout creates a Stripe Checkout session for a user who
+// has not yet created an account. This is a public endpoint (no auth required).
+// The Firebase account is created on the frontend only after payment succeeds.
+func (h *StripeHandler) CreateOnboardingCheckout(w http.ResponseWriter, r *http.Request) {
+	var body struct {
+		Email string `json:"email"`
+		Tier  string `json:"tier"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+		writeError(w, http.StatusBadRequest, "BAD_REQUEST", "Invalid request body")
+		return
+	}
+
+	if body.Email == "" {
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "Email is required")
+		return
+	}
+
+	if body.Tier == "" {
+		body.Tier = "premium"
+	}
+
+	tier := domain.SubscriptionTier(body.Tier)
+	if tier != domain.TierPremium && tier != domain.TierPro {
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "Tier must be 'premium' or 'pro'")
+		return
+	}
+
+	priceID, err := h.priceIDForTier(tier)
+	if err != nil {
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", err.Error())
+		return
+	}
+
+	params := &stripe.CheckoutSessionParams{
+		Mode: stripe.String(string(stripe.CheckoutSessionModeSubscription)),
+		LineItems: []*stripe.CheckoutSessionLineItemParams{
+			{
+				Price:    stripe.String(priceID),
+				Quantity: stripe.Int64(1),
+			},
+		},
+		SuccessURL:    stripe.String(h.cfg.FrontendURL + "/subscribe?payment=success&session_id={CHECKOUT_SESSION_ID}"),
+		CancelURL:     stripe.String(h.cfg.FrontendURL + "/subscribe?payment=cancelled"),
+		CustomerEmail: stripe.String(body.Email),
+	}
+	params.AddMetadata("tier", string(tier))
+	params.AddMetadata("onboarding", "true")
+
+	s, err := checkoutsession.New(params)
+	if err != nil {
+		log.Printf("Failed to create onboarding checkout session: %v", err)
+		writeError(w, http.StatusInternalServerError, "STRIPE_ERROR", "Failed to create checkout session")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]string{"url": s.URL})
+}
+
+// CreatePortalSession creates a Stripe Billing Portal session so the user can
+// manage their subscription (cancel, update payment method, view invoices).
+func (h *StripeHandler) CreatePortalSession(w http.ResponseWriter, r *http.Request) {
+	userID := middleware.GetUserID(r.Context())
+
+	user, err := h.users.GetByID(r.Context(), userID)
+	if err != nil || user == nil {
+		log.Printf("Portal: failed to get user %s: %v", userID, err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Failed to load user")
+		return
+	}
+
+	if user.StripeCustomerID == nil || *user.StripeCustomerID == "" {
+		writeError(w, http.StatusBadRequest, "NO_CUSTOMER", "No Stripe customer on file")
+		return
+	}
+
+	params := &stripe.BillingPortalSessionParams{
+		Customer:  user.StripeCustomerID,
+		ReturnURL: stripe.String(h.cfg.FrontendURL + "/account"),
+	}
+
+	s, err := portalsession.New(params)
+	if err != nil {
+		log.Printf("Portal: failed to create portal session: %v", err)
+		writeError(w, http.StatusInternalServerError, "STRIPE_ERROR", "Failed to create portal session")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]string{"url": s.URL})
+}
+
+// HandleWebhook processes incoming Stripe webhook events.
+func (h *StripeHandler) HandleWebhook(w http.ResponseWriter, r *http.Request) {
+	payload, err := io.ReadAll(io.LimitReader(r.Body, webhookMaxBodyBytes))
+	if err != nil {
+		log.Printf("Error reading webhook body: %v", err)
+		w.WriteHeader(http.StatusServiceUnavailable)
+		return
+	}
+
+	sig := r.Header.Get("Stripe-Signature")
+	event, err := webhook.ConstructEvent(payload, sig, h.cfg.StripeWebhookSecret)
+	if err != nil {
+		log.Printf("Webhook signature verification failed: %v", err)
+		w.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
+	switch event.Type {
+	case "checkout.session.completed":
+		h.handleCheckoutCompleted(r, event)
+	case "customer.subscription.updated":
+		h.handleSubscriptionUpdated(r, event)
+	case "customer.subscription.deleted":
+		h.handleSubscriptionDeleted(r, event)
+	default:
+		log.Printf("Unhandled Stripe event type: %s", event.Type)
+	}
+
+	w.WriteHeader(http.StatusOK)
+}
+
+func (h *StripeHandler) handleCheckoutCompleted(r *http.Request, event stripe.Event) {
+	var session stripe.CheckoutSession
+	if err := json.Unmarshal(event.Data.Raw, &session); err != nil {
+		log.Printf("Error parsing checkout session: %v", err)
+		return
+	}
+
+	userID := session.ClientReferenceID
+	if userID == "" {
+		log.Println("Checkout session missing client_reference_id")
+		return
+	}
+
+	tier := domain.TierPremium
+	if t, ok := session.Metadata["tier"]; ok && domain.IsValidTier(t) {
+		tier = domain.SubscriptionTier(t)
+	}
+
+	customerID := ""
+	if session.Customer != nil {
+		customerID = session.Customer.ID
+	}
+	subscriptionID := ""
+	if session.Subscription != nil {
+		subscriptionID = session.Subscription.ID
+	}
+
+	if customerID != "" {
+		if err := h.users.UpdateStripeCustomer(r.Context(), userID, customerID); err != nil {
+			log.Printf("Failed to save Stripe customer ID: %v", err)
+		}
+	}
+
+	if subscriptionID != "" && customerID != "" {
+		if err := h.users.ActivateSubscription(r.Context(), customerID, subscriptionID, "active", tier); err != nil {
+			log.Printf("Failed to activate subscription: %v", err)
+		}
+	}
+
+	log.Printf("Checkout completed for user %s, customer %s, subscription %s, tier %s", userID, customerID, subscriptionID, tier)
+}
+
+func (h *StripeHandler) handleSubscriptionUpdated(r *http.Request, event stripe.Event) {
+	var sub stripe.Subscription
+	if err := json.Unmarshal(event.Data.Raw, &sub); err != nil {
+		log.Printf("Error parsing subscription update: %v", err)
+		return
+	}
+
+	customerID := ""
+	if sub.Customer != nil {
+		customerID = sub.Customer.ID
+	}
+	if customerID == "" {
+		return
+	}
+
+	status := string(sub.Status)
+
+	// Detect tier from the subscription's current price so that
+	// upgrades/downgrades via the Stripe portal are reflected.
+	tier := domain.TierPremium
+	if sub.Items != nil {
+		for _, item := range sub.Items.Data {
+			if item.Price != nil {
+				if t := h.cfg.TierForPriceID(item.Price.ID); t != "" {
+					tier = domain.SubscriptionTier(t)
+					break
+				}
+			}
+		}
+	}
+
+	if err := h.users.ActivateSubscription(r.Context(), customerID, sub.ID, status, tier); err != nil {
+		log.Printf("Failed to update subscription: %v", err)
+	}
+
+	log.Printf("Subscription %s updated to %s (tier %s) for customer %s", sub.ID, status, tier, customerID)
+}
+
+func (h *StripeHandler) handleSubscriptionDeleted(r *http.Request, event stripe.Event) {
+	var sub stripe.Subscription
+	if err := json.Unmarshal(event.Data.Raw, &sub); err != nil {
+		log.Printf("Error parsing subscription deletion: %v", err)
+		return
+	}
+
+	customerID := ""
+	if sub.Customer != nil {
+		customerID = sub.Customer.ID
+	}
+	if customerID == "" {
+		return
+	}
+
+	if err := h.users.UpdateSubscriptionStatus(r.Context(), customerID, "canceled"); err != nil {
+		log.Printf("Failed to mark subscription canceled: %v", err)
+	}
+
+	log.Printf("Subscription canceled for customer %s", customerID)
+}

backend/internal/middleware/auth.go

@@ -8,8 +8,8 @@ import (
 	"net/http"
 	"strings"
 
-	fbauth "github.com/kjannette/koin-ping/backend-go/internal/firebase"
-	"github.com/kjannette/koin-ping/backend-go/internal/models"
+	fbauth "github.com/kjannette/koin-ping/backend/internal/firebase"
+	"github.com/kjannette/koin-ping/backend/internal/models"
 )
 
 type contextKey string
@@ -17,6 +17,7 @@ type contextKey string
 const (
 	UserIDKey    contextKey = "user_id"
 	UserEmailKey contextKey = "user_email"
+	UserTierKey  contextKey = "user_tier"
 )
 
 type errorResponse struct {
@@ -94,12 +95,50 @@ func Authenticate(userModel *models.UserModel) func(http.Handler) http.Handler {
 
 			ctx := context.WithValue(r.Context(), UserIDKey, user.ID)
 			ctx = context.WithValue(ctx, UserEmailKey, email)
+			ctx = context.WithValue(ctx, UserTierKey, string(user.SubscriptionTier))
 
 			next.ServeHTTP(w, r.WithContext(ctx))
 		})
 	}
 }
 
+// RequireSubscription blocks requests from users without an active subscription.
+// Must be applied after Authenticate.
+func RequireSubscription(userModel *models.UserModel) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			userID := GetUserID(r.Context())
+			if userID == "" {
+				writeJSON(w, http.StatusUnauthorized, errorResponse{
+					Error:   "UNAUTHORIZED",
+					Message: "Authentication required",
+				})
+				return
+			}
+
+			user, err := userModel.GetByID(r.Context(), userID)
+			if err != nil || user == nil {
+				log.Printf("RequireSubscription: failed to load user %s: %v", userID, err)
+				writeJSON(w, http.StatusInternalServerError, errorResponse{
+					Error:   "INTERNAL_ERROR",
+					Message: "Failed to verify subscription",
+				})
+				return
+			}
+
+			if user.SubscriptionStatus != "active" && user.SubscriptionStatus != "trialing" {
+				writeJSON(w, http.StatusForbidden, errorResponse{
+					Error:   "SUBSCRIPTION_REQUIRED",
+					Message: "An active subscription is required to use this feature",
+				})
+				return
+			}
+
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
 func GetUserID(ctx context.Context) string {
 	if v, ok := ctx.Value(UserIDKey).(string); ok {
 		return v
@@ -113,3 +152,10 @@ func GetUserEmail(ctx context.Context) string {
 	}
 	return ""
 }
+
+func GetUserTier(ctx context.Context) string {
+	if v, ok := ctx.Value(UserTierKey).(string); ok {
+		return v
+	}
+	return "free"
+}

backend/internal/middleware/auth_test.go

@@ -0,0 +1,60 @@
+package middleware
+
+import (
+	"context"
+	"testing"
+)
+
+func TestGetUserID_Empty(t *testing.T) {
+	t.Parallel()
+
+	ctx := context.Background()
+	if id := GetUserID(ctx); id != "" {
+		t.Errorf("expected empty user ID, got %q", id)
+	}
+}
+
+func TestGetUserID_Set(t *testing.T) {
+	t.Parallel()
+
+	ctx := context.WithValue(context.Background(), UserIDKey, "abc-123")
+	if id := GetUserID(ctx); id != "abc-123" {
+		t.Errorf("expected abc-123, got %q", id)
+	}
+}
+
+func TestGetUserEmail_Empty(t *testing.T) {
+	t.Parallel()
+
+	ctx := context.Background()
+	if email := GetUserEmail(ctx); email != "" {
+		t.Errorf("expected empty email, got %q", email)
+	}
+}
+
+func TestGetUserEmail_Set(t *testing.T) {
+	t.Parallel()
+
+	ctx := context.WithValue(context.Background(), UserEmailKey, "test@example.com")
+	if email := GetUserEmail(ctx); email != "test@example.com" {
+		t.Errorf("expected test@example.com, got %q", email)
+	}
+}
+
+func TestGetUserTier_Default(t *testing.T) {
+	t.Parallel()
+
+	ctx := context.Background()
+	if tier := GetUserTier(ctx); tier != "free" {
+		t.Errorf("expected default tier 'free', got %q", tier)
+	}
+}
+
+func TestGetUserTier_Set(t *testing.T) {
+	t.Parallel()
+
+	ctx := context.WithValue(context.Background(), UserTierKey, "pro")
+	if tier := GetUserTier(ctx); tier != "pro" {
+		t.Errorf("expected 'pro', got %q", tier)
+	}
+}

backend/internal/models/address.go

@@ -6,7 +6,7 @@ import (
 
 	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
 )
 
 type AddressModel struct {
@@ -55,12 +55,14 @@ func (m *AddressModel) ListByUser(ctx context.Context, userID string) ([]domain.
 	return addresses, rows.Err()
 }
 
-// ListAll returns all addresses system-wide (used by the poller).
+// ListAll returns addresses for users with an active subscription (used by the poller).
 func (m *AddressModel) ListAll(ctx context.Context) ([]domain.Address, error) {
 	rows, err := m.pool.Query(ctx,
-		`SELECT id, user_id, address, label, created_at
-		 FROM addresses
-		 ORDER BY created_at DESC`,
+		`SELECT a.id, a.user_id, a.address, a.label, a.created_at
+		 FROM addresses a
+		 JOIN users u ON u.id = a.user_id
+		 WHERE u.subscription_status IN ('active', 'trialing')
+		 ORDER BY a.created_at DESC`,
 	)
 	if err != nil {
 		return nil, err
@@ -125,6 +127,15 @@ func (m *AddressModel) UpdateLabel(ctx context.Context, id int, userID string, l
 	return &a, nil
 }
 
+func (m *AddressModel) CountByUser(ctx context.Context, userID string) (int, error) {
+	var count int
+	err := m.pool.QueryRow(ctx,
+		`SELECT COUNT(*) FROM addresses WHERE user_id = $1`,
+		userID,
+	).Scan(&count)
+	return count, err
+}
+
 func (m *AddressModel) Remove(ctx context.Context, id int, userID string) (bool, error) {
 	tag, err := m.pool.Exec(ctx,
 		`DELETE FROM addresses WHERE id = $1 AND user_id = $2`,

backend/internal/models/alert_event.go

@@ -6,7 +6,7 @@ import (
 
 	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
 )
 
 type AlertEventModel struct {

backend/internal/models/alert_rule.go

@@ -0,0 +1,142 @@
+package models
+
+import (
+	"context"
+	"errors"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
+)
+
+type AlertRuleModel struct {
+	pool *pgxpool.Pool
+}
+
+func NewAlertRuleModel(pool *pgxpool.Pool) *AlertRuleModel {
+	return &AlertRuleModel{pool: pool}
+}
+
+func (m *AlertRuleModel) Create(ctx context.Context, addressID int, alertType domain.AlertType, threshold, minimum, maximum *float64) (*domain.AlertRule, error) {
+	var r domain.AlertRule
+	err := m.pool.QueryRow(ctx,
+		`INSERT INTO alert_rules (address_id, type, threshold, minimum, maximum, enabled)
+		 VALUES ($1, $2, $3, $4, $5, TRUE)
+		 RETURNING id, address_id, type, threshold, minimum, maximum, enabled, created_at`,
+		addressID, alertType.String(), threshold, minimum, maximum,
+	).Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Minimum, &r.Maximum, &r.Enabled, &r.CreatedAt)
+	if err != nil {
+		return nil, err
+	}
+	return &r, nil
+}
+
+func (m *AlertRuleModel) ListByAddress(ctx context.Context, addressID int) ([]domain.AlertRule, error) {
+	rows, err := m.pool.Query(ctx,
+		`SELECT id, address_id, type, threshold, minimum, maximum, enabled, created_at
+		 FROM alert_rules
+		 WHERE address_id = $1
+		 ORDER BY created_at DESC`,
+		addressID,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var rules []domain.AlertRule
+	for rows.Next() {
+		var r domain.AlertRule
+		if err := rows.Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Minimum, &r.Maximum, &r.Enabled, &r.CreatedAt); err != nil {
+			return nil, err
+		}
+		rules = append(rules, r)
+	}
+	return rules, rows.Err()
+}
+
+func (m *AlertRuleModel) FindByID(ctx context.Context, id int, userID *string) (*domain.AlertRule, error) {
+	var r domain.AlertRule
+	var err error
+
+	if userID != nil {
+		err = m.pool.QueryRow(ctx,
+			`SELECT ar.id, ar.address_id, ar.type, ar.threshold, ar.minimum, ar.maximum, ar.enabled, ar.created_at
+			 FROM alert_rules ar
+			 JOIN addresses a ON a.id = ar.address_id
+			 WHERE ar.id = $1 AND a.user_id = $2`,
+			id, *userID,
+		).Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Minimum, &r.Maximum, &r.Enabled, &r.CreatedAt)
+	} else {
+		err = m.pool.QueryRow(ctx,
+			`SELECT id, address_id, type, threshold, minimum, maximum, enabled, created_at
+			 FROM alert_rules
+			 WHERE id = $1`,
+			id,
+		).Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Minimum, &r.Maximum, &r.Enabled, &r.CreatedAt)
+	}
+
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, nil
+		}
+		return nil, err
+	}
+	return &r, nil
+}
+
+func (m *AlertRuleModel) UpdateEnabled(ctx context.Context, id int, enabled bool) (*domain.AlertRule, error) {
+	var r domain.AlertRule
+	err := m.pool.QueryRow(ctx,
+		`UPDATE alert_rules
+		 SET enabled = $2
+		 WHERE id = $1
+		 RETURNING id, address_id, type, threshold, minimum, maximum, enabled, created_at`,
+		id, enabled,
+	).Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Minimum, &r.Maximum, &r.Enabled, &r.CreatedAt)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, nil
+		}
+		return nil, err
+	}
+	return &r, nil
+}
+
+func (m *AlertRuleModel) UpdateThresholds(ctx context.Context, id int, minimum, maximum *float64) (*domain.AlertRule, error) {
+	var r domain.AlertRule
+	err := m.pool.QueryRow(ctx,
+		`UPDATE alert_rules
+		 SET minimum = $2, maximum = $3
+		 WHERE id = $1
+		 RETURNING id, address_id, type, threshold, minimum, maximum, enabled, created_at`,
+		id, minimum, maximum,
+	).Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Minimum, &r.Maximum, &r.Enabled, &r.CreatedAt)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, nil
+		}
+		return nil, err
+	}
+	return &r, nil
+}
+
+func (m *AlertRuleModel) CountDistinctTypesByAddress(ctx context.Context, addressID int) (int, error) {
+	var count int
+	err := m.pool.QueryRow(ctx,
+		`SELECT COUNT(DISTINCT type) FROM alert_rules WHERE address_id = $1`,
+		addressID,
+	).Scan(&count)
+	return count, err
+}
+
+func (m *AlertRuleModel) Remove(ctx context.Context, id int) (bool, error) {
+	tag, err := m.pool.Exec(ctx,
+		`DELETE FROM alert_rules WHERE id = $1`,
+		id,
+	)
+	if err != nil {
+		return false, err
+	}
+	return tag.RowsAffected() > 0, nil
+}

backend/internal/models/checkpoint.go

@@ -7,7 +7,7 @@ import (
 
 	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
 )
 
 type CheckpointModel struct {

backend/internal/models/notification_config.go

@@ -6,7 +6,7 @@ import (
 
 	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
 )
 
 type NotificationConfigModel struct {
@@ -77,10 +77,12 @@ func (m *NotificationConfigModel) Remove(ctx context.Context, userID string) (bo
 
 func (m *NotificationConfigModel) ListEnabled(ctx context.Context) ([]domain.NotificationConfig, error) {
 	rows, err := m.pool.Query(ctx,
-		`SELECT user_id, discord_webhook_url, telegram_chat_id, telegram_bot_token,
-		        email, slack_webhook_url
-		 FROM user_notification_configs
-		 WHERE notification_enabled = TRUE`,
+		`SELECT nc.user_id, nc.discord_webhook_url, nc.telegram_chat_id, nc.telegram_bot_token,
+		        nc.email, nc.slack_webhook_url
+		 FROM user_notification_configs nc
+		 JOIN users u ON u.id = nc.user_id
+		 WHERE nc.notification_enabled = TRUE
+		   AND u.subscription_status IN ('active', 'trialing')`,
 	)
 	if err != nil {
 		return nil, err

backend/internal/models/user.go

@@ -0,0 +1,111 @@
+package models
+
+import (
+	"context"
+	"errors"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
+)
+
+type UserModel struct {
+	pool *pgxpool.Pool
+}
+
+func NewUserModel(pool *pgxpool.Pool) *UserModel {
+	return &UserModel{pool: pool}
+}
+
+const userColumns = `id, firebase_uid, email, display_name,
+	stripe_customer_id, stripe_subscription_id, subscription_status,
+	subscription_tier, subscription_created_at, created_at, updated_at`
+
+func scanUser(row pgx.Row) (*domain.User, error) {
+	var u domain.User
+	err := row.Scan(
+		&u.ID, &u.FirebaseUID, &u.Email, &u.DisplayName,
+		&u.StripeCustomerID, &u.StripeSubscriptionID, &u.SubscriptionStatus,
+		&u.SubscriptionTier, &u.SubscriptionCreatedAt, &u.CreatedAt, &u.UpdatedAt,
+	)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, nil //nolint:nilnil
+		}
+		return nil, err
+	}
+	return &u, nil
+}
+
+// FindOrCreateByFirebaseUID returns the local user for a Firebase UID,
+// creating one if it doesn't exist yet. On conflict (returning user) the
+// updated_at timestamp is refreshed.
+func (m *UserModel) FindOrCreateByFirebaseUID(ctx context.Context, firebaseUID, email string) (*domain.User, error) {
+	row := m.pool.QueryRow(ctx,
+		`INSERT INTO users (firebase_uid, email)
+		 VALUES ($1, $2)
+		 ON CONFLICT (firebase_uid) DO UPDATE SET updated_at = NOW()
+		 RETURNING `+userColumns,
+		firebaseUID, email,
+	)
+	return scanUser(row)
+}
+
+func (m *UserModel) GetByID(ctx context.Context, id string) (*domain.User, error) {
+	row := m.pool.QueryRow(ctx,
+		`SELECT `+userColumns+` FROM users WHERE id = $1`, id,
+	)
+	return scanUser(row)
+}
+
+func (m *UserModel) UpdateStripeCustomer(ctx context.Context, userID, stripeCustomerID string) error {
+	_, err := m.pool.Exec(ctx,
+		`UPDATE users SET stripe_customer_id = $2, updated_at = NOW() WHERE id = $1`,
+		userID, stripeCustomerID,
+	)
+	return err
+}
+
+func (m *UserModel) ActivateSubscription(ctx context.Context, stripeCustomerID, subscriptionID, status string, tier domain.SubscriptionTier) error {
+	_, err := m.pool.Exec(ctx,
+		`UPDATE users
+		 SET stripe_subscription_id = $2,
+		     subscription_status = $3,
+		     subscription_tier = $4,
+		     subscription_created_at = COALESCE(subscription_created_at, NOW()),
+		     updated_at = NOW()
+		 WHERE stripe_customer_id = $1`,
+		stripeCustomerID, subscriptionID, status, string(tier),
+	)
+	return err
+}
+
+func (m *UserModel) UpdateSubscriptionTier(ctx context.Context, userID string, tier domain.SubscriptionTier) error {
+	_, err := m.pool.Exec(ctx,
+		`UPDATE users SET subscription_tier = $2, updated_at = NOW() WHERE id = $1`,
+		userID, string(tier),
+	)
+	return err
+}
+
+func (m *UserModel) ActivateFreeTier(ctx context.Context, userID string) error {
+	_, err := m.pool.Exec(ctx,
+		`UPDATE users
+		 SET subscription_status = 'active',
+		     subscription_tier = 'free',
+		     subscription_created_at = COALESCE(subscription_created_at, NOW()),
+		     updated_at = NOW()
+		 WHERE id = $1`,
+		userID,
+	)
+	return err
+}
+
+func (m *UserModel) UpdateSubscriptionStatus(ctx context.Context, stripeCustomerID, status string) error {
+	_, err := m.pool.Exec(ctx,
+		`UPDATE users SET subscription_status = $2, updated_at = NOW()
+		 WHERE stripe_customer_id = $1`,
+		stripeCustomerID, status,
+	)
+	return err
+}

backend/internal/notifications/discord.go

@@ -21,17 +21,14 @@ const (
 	colorBlue   = 0x0099ff
 )
 
-// discordHTTPClient is a shared HTTP client with a timeout for Discord requests.
 var discordHTTPClient = &http.Client{ //nolint:gochecknoglobals
 	Timeout: discordHTTPTimeoutSeconds * time.Second,
 }
 
-// DiscordNotifier sends alert notifications via a Discord webhook.
+//  sends alert notifications via a Discord webhook.
 type DiscordNotifier struct {
 	WebhookURL string
 }
-
-// Send implements Notifier for Discord.
 func (d *DiscordNotifier) Send(_ context.Context, message string, meta AlertMetadata) error {
 	_, err := SendDiscordNotification(d.WebhookURL, message, meta)
 	return err
@@ -104,8 +101,12 @@ func SendDiscordNotification(webhookURL, message string, meta AlertMetadata) (bo
 	defer resp.Body.Close()
 
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		err := fmt.Errorf("discord webhook failed: HTTP %d", resp.StatusCode)
 		log.Printf("Discord webhook failed: HTTP %d", resp.StatusCode)
-		return false, fmt.Errorf("discord webhook failed: HTTP %d", resp.StatusCode)
+		if isPermanentStatusCode(resp.StatusCode) {
+			return false, &PermanentError{Err: err}
+		}
+		return false, err
 	}
 
 	return true, nil

backend/internal/notifications/email.go

@@ -10,14 +10,12 @@ import (
 	"time"
 )
 
-// EmailNotifier sends alert notifications via email (Resend).
 type EmailNotifier struct {
 	APIKey string
 	From   string
 	To     string
 }
 
-// Send implements Notifier for email.
 func (e *EmailNotifier) Send(_ context.Context, message string, meta AlertMetadata) error {
 	_, err := SendEmailNotification(e.APIKey, e.From, e.To, message, meta)
 	return err
@@ -99,8 +97,12 @@ func SendEmailNotification(apiKey, fromAddress, toAddress, message string, meta
 	defer resp.Body.Close()
 
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		err := fmt.Errorf("resend API failed: HTTP %d", resp.StatusCode)
 		log.Printf("Resend API failed: HTTP %d", resp.StatusCode)
-		return false, fmt.Errorf("resend API failed: HTTP %d", resp.StatusCode)
+		if isPermanentStatusCode(resp.StatusCode) {
+			return false, &PermanentError{Err: err}
+		}
+		return false, err
 	}
 
 	return true, nil

backend/internal/notifications/notifier.go

@@ -0,0 +1,38 @@
+package notifications
+
+import (
+	"context"
+	"errors"
+	"net/http"
+)
+
+// AlertMetadata holds context about the alert being sent.
+type AlertMetadata struct {
+	TxHash       string
+	AddressLabel string
+	AlertType    string
+	Address      string
+}
+
+type Notifier interface {
+	Send(ctx context.Context, message string, meta AlertMetadata) error
+}
+
+// PermanentError wraps errors that should not be retried (e.g. 401, 403, 404).
+type PermanentError struct{ Err error }
+
+func (e *PermanentError) Error() string { return e.Err.Error() }
+func (e *PermanentError) Unwrap() error { return e.Err }
+
+func IsPermanent(err error) bool {
+	var p *PermanentError
+	return errors.As(err, &p)
+}
+
+func isPermanentStatusCode(code int) bool {
+	return code == http.StatusUnauthorized ||
+		code == http.StatusForbidden ||
+		code == http.StatusNotFound ||
+		code == http.StatusMethodNotAllowed ||
+		code == http.StatusGone
+}

backend/internal/notifications/slack.go

@@ -87,8 +87,12 @@ func SendSlackNotification(webhookURL, message string, meta AlertMetadata) (bool
 	defer resp.Body.Close()
 
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		err := fmt.Errorf("slack webhook failed: HTTP %d", resp.StatusCode)
 		log.Printf("Slack webhook failed: HTTP %d", resp.StatusCode)
-		return false, fmt.Errorf("slack webhook failed: HTTP %d", resp.StatusCode)
+		if isPermanentStatusCode(resp.StatusCode) {
+			return false, &PermanentError{Err: err}
+		}
+		return false, err
 	}
 
 	return true, nil

backend/internal/notifications/telegram.go

@@ -63,8 +63,12 @@ func SendTelegramNotification(botToken, chatID, message string, meta AlertMetada
 	defer resp.Body.Close()
 
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		err := fmt.Errorf("telegram API failed: HTTP %d", resp.StatusCode)
 		log.Printf("Telegram API failed: HTTP %d", resp.StatusCode)
-		return false, fmt.Errorf("telegram API failed: HTTP %d", resp.StatusCode)
+		if isPermanentStatusCode(resp.StatusCode) {
+			return false, &PermanentError{Err: err}
+		}
+		return false, err
 	}
 
 	return true, nil

backend/internal/protocols/ethereum/jsonrpc.go

@@ -12,18 +12,20 @@ import (
 	"strings"
 	"time"
 
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
 )
 
 const (
-	rpcTimeoutMS    = 30000
-	rpcMaxRetries   = 3
-	rpcRetryBaseMS  = 1000
+	rpcTimeoutMS      = 30000
+	rpcMaxRetries     = 3
+	rpcRetryBaseMS    = 2000
+	rpcMinIntervalMS  = 1000
 )
 
 type JsonRpcEthereum struct {
-	rpcURL string
-	client *http.Client
+	rpcURL     string
+	client     *http.Client
+	lastCallAt time.Time
 }
 
 func NewJsonRpcEthereum(rpcURL string) (*JsonRpcEthereum, error) {
@@ -58,6 +60,8 @@ type rpcError struct {
 }
 
 func (j *JsonRpcEthereum) callRPC(ctx context.Context, method string, params ...interface{}) (json.RawMessage, error) {
+	j.throttle(ctx)
+
 	if params == nil {
 		params = []interface{}{}
 	}
@@ -72,7 +76,25 @@ func (j *JsonRpcEthereum) callRPC(ctx context.Context, method string, params ...
 		return nil, fmt.Errorf("marshal RPC request: %w", err)
 	}
 
-	return j.callWithRetry(ctx, method, body)
+	result, callErr := j.callWithRetry(ctx, method, body)
+	j.lastCallAt = time.Now()
+
+	return result, callErr
+}
+
+func (j *JsonRpcEthereum) throttle(ctx context.Context) {
+	if j.lastCallAt.IsZero() {
+		return
+	}
+	minInterval := time.Duration(rpcMinIntervalMS) * time.Millisecond
+	elapsed := time.Since(j.lastCallAt)
+	if elapsed >= minInterval {
+		return
+	}
+	select {
+	case <-ctx.Done():
+	case <-time.After(minInterval - elapsed):
+	}
 }
 
 // callWithRetry executes a JSON-RPC POST with exponential backoff on transient errors.

backend/internal/protocols/ethereum/observer.go

@@ -3,7 +3,7 @@ package ethereum
 import (
 	"context"
 
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
 )
 
 // EthereumObserver defines the interface for blockchain interaction.

backend/internal/services/email_digest.go

@@ -9,7 +9,7 @@ import (
 	"net/http"
 	"time"
 
-	"github.com/kjannette/koin-ping/backend-go/internal/models"
+	"github.com/kjannette/koin-ping/backend/internal/models"
 )
 
 const (
@@ -20,7 +20,7 @@ const (
 
 var digestHTTPClient = &http.Client{Timeout: emailHTTPTimeout} //nolint:gochecknoglobals
 
-// EmailDigestService handles email setup and digest sending via Resend.
+// handles email setup and digest sending via Resend.
 type EmailDigestService struct {
 	apiKey      string
 	fromAddress string
@@ -66,7 +66,6 @@ func (s *EmailDigestService) SetupEmail(toAddress string) error {
 	return s.send(toAddress, "Koin Ping — Email Alerts Configured", html)
 }
 
-// SendDigest compiles recent alert events for a user and sends a digest email.
 func (s *EmailDigestService) SendDigest(ctx context.Context, userID, toAddress string) error {
 	if !s.Configured() {
 		return fmt.Errorf("email service not configured: RESEND_API_KEY not set") //nolint:err113
@@ -131,8 +130,6 @@ func (s *EmailDigestService) SendDigest(ctx context.Context, userID, toAddress s
 	return s.send(toAddress, subject, html)
 }
 
-// SendDigestsForAllUsers sends a digest email to every user that has
-// notifications enabled and an email configured.
 func (s *EmailDigestService) SendDigestsForAllUsers(ctx context.Context) (int, error) {
 	if !s.Configured() {
 		return 0, nil

backend/internal/services/evaluator.go

@@ -4,19 +4,23 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"sync"
 	"time"
 
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
-	"github.com/kjannette/koin-ping/backend-go/internal/models"
-	"github.com/kjannette/koin-ping/backend-go/internal/notifications"
-	"github.com/kjannette/koin-ping/backend-go/internal/protocols/ethereum"
-	"github.com/kjannette/koin-ping/backend-go/internal/wei"
+	"golang.org/x/sync/semaphore"
+
+	"github.com/kjannette/koin-ping/backend/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/models"
+	"github.com/kjannette/koin-ping/backend/internal/notifications"
+	"github.com/kjannette/koin-ping/backend/internal/protocols/ethereum"
+	"github.com/kjannette/koin-ping/backend/internal/wei"
 )
 
 const (
 	notificationTimeout    = 30 * time.Second
 	notificationMaxRetries = 3
 	notificationRetryBase  = time.Second
+	maxConcurrentNotifications = 5
 )
 
 type EvaluatorService struct {
@@ -24,9 +28,10 @@ type EvaluatorService struct {
 	alertRules   *models.AlertRuleModel
 	alertEvents  *models.AlertEventModel
 	addresses    *models.AddressModel
+	users        *models.UserModel
 	notifConfigs *models.NotificationConfigModel
-	resendAPIKey string
-	emailFrom    string
+	notifSem     *semaphore.Weighted
+	notifWg      sync.WaitGroup
 }
 
 func NewEvaluatorService(
@@ -34,18 +39,17 @@ func NewEvaluatorService(
 	alertRules *models.AlertRuleModel,
 	alertEvents *models.AlertEventModel,
 	addresses *models.AddressModel,
+	users *models.UserModel,
 	notifConfigs *models.NotificationConfigModel,
-	resendAPIKey string,
-	emailFrom string,
 ) *EvaluatorService {
 	return &EvaluatorService{
 		eth:          eth,
 		alertRules:   alertRules,
 		alertEvents:  alertEvents,
 		addresses:    addresses,
+		users:        users,
 		notifConfigs: notifConfigs,
-		resendAPIKey: resendAPIKey,
-		emailFrom:    emailFrom,
+		notifSem:     semaphore.NewWeighted(maxConcurrentNotifications),
 	}
 }
 
@@ -97,9 +101,9 @@ func (s *EvaluatorService) evaluateObservation(ctx context.Context, obs domain.O
 func (s *EvaluatorService) ruleMatches(ctx context.Context, rule domain.AlertRule, obs domain.ObservedTx) (bool, error) {
 	switch rule.Type {
 	case domain.AlertIncomingTx:
-		return obs.Direction == domain.DirectionIncoming, nil
+		return s.matchesDirectionalTx(rule, obs, domain.DirectionIncoming)
 	case domain.AlertOutgoingTx:
-		return obs.Direction == domain.DirectionOutgoing, nil
+		return s.matchesDirectionalTx(rule, obs, domain.DirectionOutgoing)
 	case domain.AlertLargeTransfer:
 		return s.matchesLargeTransfer(rule, obs)
 	case domain.AlertBalanceBelow:
@@ -110,6 +114,42 @@ func (s *EvaluatorService) ruleMatches(ctx context.Context, rule domain.AlertRul
 	}
 }
 
+func (s *EvaluatorService) matchesDirectionalTx(rule domain.AlertRule, obs domain.ObservedTx, expected domain.Direction) (bool, error) {
+	if obs.Direction != expected {
+		return false, nil
+	}
+
+	if rule.Minimum != nil {
+		minWei, err := wei.FromEth(*rule.Minimum)
+		if err != nil {
+			return false, err
+		}
+		aboveMin, err := wei.GreaterThanOrEqual(obs.Value, minWei)
+		if err != nil {
+			return false, err
+		}
+		if !aboveMin {
+			return false, nil
+		}
+	}
+
+	if rule.Maximum != nil {
+		maxWei, err := wei.FromEth(*rule.Maximum)
+		if err != nil {
+			return false, err
+		}
+		belowMax, err := wei.LessThanOrEqual(obs.Value, maxWei)
+		if err != nil {
+			return false, err
+		}
+		if !belowMax {
+			return false, nil
+		}
+	}
+
+	return true, nil
+}
+
 func (s *EvaluatorService) matchesLargeTransfer(rule domain.AlertRule, obs domain.ObservedTx) (bool, error) {
 	if rule.Threshold == nil {
 		return false, nil
@@ -189,7 +229,14 @@ func (s *EvaluatorService) fireAlert(ctx context.Context, rule domain.AlertRule,
 	if addr != nil {
 		userID := addr.UserID
 		address := addr.Address
+		if err := s.notifSem.Acquire(ctx, 1); err != nil {
+			log.Printf("Failed to acquire notification semaphore for rule %d: %v", rule.ID, err)
+			return nil
+		}
+		s.notifWg.Add(1)
 		go func() {
+			defer s.notifSem.Release(1)
+			defer s.notifWg.Done()
 			notifCtx, cancel := context.WithTimeout(context.Background(), notificationTimeout)
 			defer cancel()
 			s.sendNotification(notifCtx, userID, message, obs, addressLabel, rule, address)
@@ -199,14 +246,21 @@ func (s *EvaluatorService) fireAlert(ctx context.Context, rule domain.AlertRule,
 	return nil
 }
 
-func (s *EvaluatorService) buildNotifiers(cfg *domain.NotificationConfig) []notifications.Notifier {
+// WaitForNotifications blocks until all in-flight notification goroutines finish.
+func (s *EvaluatorService) WaitForNotifications() {
+	s.notifWg.Wait()
+}
+
+func (s *EvaluatorService) buildNotifiers(cfg *domain.NotificationConfig, limits domain.TierLimits) []notifications.Notifier {
 	var notifiers []notifications.Notifier
 
-	if cfg.DiscordWebhookURL != nil && *cfg.DiscordWebhookURL != "" {
+	if limits.ChannelAllowed("discord") &&
+		cfg.DiscordWebhookURL != nil && *cfg.DiscordWebhookURL != "" {
 		notifiers = append(notifiers, &notifications.DiscordNotifier{WebhookURL: *cfg.DiscordWebhookURL})
 	}
 
-	if cfg.TelegramBotToken != nil && *cfg.TelegramBotToken != "" &&
+	if limits.ChannelAllowed("telegram") &&
+		cfg.TelegramBotToken != nil && *cfg.TelegramBotToken != "" &&
 		cfg.TelegramChatID != nil && *cfg.TelegramChatID != "" {
 		notifiers = append(notifiers, &notifications.TelegramNotifier{
 			BotToken: *cfg.TelegramBotToken,
@@ -214,17 +268,12 @@ func (s *EvaluatorService) buildNotifiers(cfg *domain.NotificationConfig) []noti
 		})
 	}
 
-	if cfg.SlackWebhookURL != nil && *cfg.SlackWebhookURL != "" {
+	if limits.ChannelAllowed("slack") &&
+		cfg.SlackWebhookURL != nil && *cfg.SlackWebhookURL != "" {
 		notifiers = append(notifiers, &notifications.SlackNotifier{WebhookURL: *cfg.SlackWebhookURL})
 	}
 
-	if cfg.Email != nil && *cfg.Email != "" {
-		notifiers = append(notifiers, &notifications.EmailNotifier{
-			APIKey: s.resendAPIKey,
-			From:   s.emailFrom,
-			To:     *cfg.Email,
-		})
-	}
+	// Email is delivered exclusively via the daily digest service, never real-time.
 
 	return notifiers
 }
@@ -242,8 +291,14 @@ func sendWithRetry(ctx context.Context, n notifications.Notifier, message string
 		}
 
 		if err := n.Send(ctx, message, meta); err != nil {
-			log.Printf("Notification attempt %d/%d failed: %v", attempt+1, notificationMaxRetries, err)
 			lastErr = err
+
+			if notifications.IsPermanent(err) {
+				log.Printf("Permanent notification failure, skipping retries: %v", err)
+				return err
+			}
+
+			log.Printf("Notification attempt %d/%d failed: %v", attempt+1, notificationMaxRetries, err)
 			continue
 		}
 
@@ -264,6 +319,13 @@ func (s *EvaluatorService) sendNotification(ctx context.Context, userID, message
 		return
 	}
 
+	user, err := s.users.GetByID(ctx, userID)
+	if err != nil || user == nil {
+		log.Printf("Failed to load user %s for tier check in notification: %v", userID, err)
+		return
+	}
+	limits := domain.GetTierLimits(user.SubscriptionTier)
+
 	meta := notifications.AlertMetadata{
 		TxHash:       obs.Hash,
 		AddressLabel: addressLabel,
@@ -271,7 +333,7 @@ func (s *EvaluatorService) sendNotification(ctx context.Context, userID, message
 		Address:      address,
 	}
 
-	for _, n := range s.buildNotifiers(notifConfig) {
+	for _, n := range s.buildNotifiers(notifConfig, limits) {
 		if err := sendWithRetry(ctx, n, message, meta); err != nil {
 			log.Printf("Notification channel failed for user %s after retries: %v", userID, err)
 		} else {

backend/internal/services/observer.go

@@ -5,9 +5,9 @@ import (
 	"log"
 	"strings"
 
-	"github.com/kjannette/koin-ping/backend-go/internal/domain"
-	"github.com/kjannette/koin-ping/backend-go/internal/models"
-	"github.com/kjannette/koin-ping/backend-go/internal/protocols/ethereum"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/models"
+	"github.com/kjannette/koin-ping/backend/internal/protocols/ethereum"
 )
 
 const maxBlocksPerRun = 100

backend/internal/wei/converter.go

@@ -90,6 +90,14 @@ func LessThan(weiA, weiB string) (bool, error) {
 	return cmp < 0, nil
 }
 
+func LessThanOrEqual(weiA, weiB string) (bool, error) {
+	cmp, err := Compare(weiA, weiB)
+	if err != nil {
+		return false, err
+	}
+	return cmp <= 0, nil
+}
+
 // FormatAsEth formats a Wei string as "X.XXXX ETH".
 func FormatAsEth(weiString string, decimals int) (string, error) {
 	eth, err := ToEth(weiString)

frontend/src/App.jsx

@@ -1,38 +1,50 @@
 import { Routes, Route, Navigate } from "react-router-dom";
 import { useAuth } from "./contexts/AuthContext";
 import Navbar from "./components/Navbar";
-import Login from "./pages/Login";
+import Login from "./pages/login/Login";
 import Signup from "./pages/Signup";
-import Onboarding from "./pages/Onboarding";
-import Addresses from "./pages/Addresses";
-import Alerts from "./pages/Alerts";
-import AlertHistory from "./pages/AlertHistory";
+import Subscribe from "./pages/subscribe/Subscribe";
+import Addresses from "./pages/addresses/Addresses";
+import Alerts from "./pages/alerts/Alerts";
+import AlertHistory from "./pages/alertHistory/AlertHistory";
+import Account from "./pages/user_account/Account";
 
 export default function App() {
-    const { currentUser } = useAuth();
-
-    if (!currentUser) {
-        return (
-            <Routes>
-                <Route path="/login" element={<Login />} />
-                <Route path="/signup" element={<Signup />} />
-                <Route path="/onboarding" element={<Onboarding />} />
-                <Route path="*" element={<Navigate to="/login" />} />
-            </Routes>
-        );
-    }
+  const { currentUser, isSubscribed } = useAuth();
 
+  if (!currentUser) {
     return (
-        <div>
-            <Navbar />
-            <Routes>
-                <Route path="/" element={<Addresses />} />
-                <Route path="/addresses" element={<Addresses />} />
-                <Route path="/alerts" element={<Alerts />} />
-                <Route path="/alertevents" element={<AlertHistory />} />
-                <Route path="/onboarding" element={<Onboarding />} />
-                <Route path="*" element={<Navigate to="/addresses" />} />
-            </Routes>
-        </div>
+      <Routes>
+        <Route path="/login" element={<Login />} />
+        <Route path="/signup" element={<Signup />} />
+        <Route path="/subscribe" element={<Subscribe />} />
+        <Route path="*" element={<Navigate to="/login" />} />
+      </Routes>
     );
+  }
+
+  if (!isSubscribed) {
+    return (
+      <Routes>
+        <Route path="/subscribe" element={<Subscribe />} />
+        <Route path="/account" element={<><Navbar /><Account /></>} />
+        <Route path="*" element={<Navigate to="/subscribe" />} />
+      </Routes>
+    );
+  }
+
+  return (
+    <div>
+      <Navbar />
+      <Routes>
+        <Route path="/" element={<Addresses />} />
+        <Route path="/addresses" element={<Addresses />} />
+        <Route path="/alerts" element={<Alerts />} />
+        <Route path="/alertevents" element={<AlertHistory />} />
+        <Route path="/account" element={<Account />} />
+        <Route path="/subscribe" element={<Subscribe />} />
+        <Route path="*" element={<Navigate to="/addresses" />} />
+      </Routes>
+    </div>
+  );
 }

frontend/src/api/account.js

@@ -0,0 +1,25 @@
+import { getAuthHeaders } from "./authHeaders";
+import { API_BASE } from "./config";
+
+export async function getAccount() {
+    const headers = await getAuthHeaders();
+    const res = await fetch(`${API_BASE}/user/account`, { headers });
+    if (!res.ok) {
+        const data = await res.json();
+        throw new Error(data.message || "Failed to load account");
+    }
+    return res.json();
+}
+
+export async function createPortalSession() {
+    const headers = await getAuthHeaders();
+    const res = await fetch(`${API_BASE}/stripe/create-portal-session`, {
+        method: "POST",
+        headers,
+    });
+    if (!res.ok) {
+        const data = await res.json();
+        throw new Error(data.message || "Failed to create portal session");
+    }
+    return res.json();
+}

frontend/src/api/alerts.jsx

@@ -129,6 +129,48 @@ export async function updateAlertStatus(alertId, enabled) {
     }
 }
 
+/**
+ * Update the min/max thresholds on an alert rule
+ * @param {number} alertId - Alert rule ID
+ * @param {number|null} minimum - Minimum amount (null to clear)
+ * @param {number|null} maximum - Maximum amount (null to clear)
+ * @returns {Promise<Object>} Updated alert rule
+ */
+export async function updateAlertThresholds(alertId, minimum, maximum) {
+    try {
+        const headers = await getAuthHeaders();
+        const response = await fetch(`${API_BASE}/alerts/${alertId}`, {
+            method: "PATCH",
+            headers: headers,
+            body: JSON.stringify({
+                update_min_max: true,
+                minimum: minimum ?? null,
+                maximum: maximum ?? null,
+            }),
+        });
+
+        if (!response.ok) {
+            let errorMessage = "Failed to update alert thresholds";
+            try {
+                const error = await response.json();
+                errorMessage = error.message || errorMessage;
+            } catch {
+                errorMessage = `Server error: ${response.status} ${response.statusText}`;
+            }
+            throw new Error(errorMessage);
+        }
+
+        return response.json();
+    } catch (error) {
+        if (error.message.includes("fetch")) {
+            throw new Error(
+                "Cannot connect to server. Is the backend running?",
+            );
+        }
+        throw error;
+    }
+}
+
 /**
  * Delete an alert rule
  * @param {number} alertId - Alert rule ID

frontend/src/api/stripe.jsx

@@ -0,0 +1,68 @@
+import { getAuthHeaders } from "./authHeaders";
+import { API_BASE } from "./config";
+
+export async function createCheckoutSession(tier = "premium") {
+    const headers = await getAuthHeaders();
+    const res = await fetch(`${API_BASE}/stripe/create-checkout-session`, {
+        method: "POST",
+        headers: { ...headers, "Content-Type": "application/json" },
+        body: JSON.stringify({ tier }),
+    });
+    if (!res.ok) {
+        const data = await res.json();
+        throw new Error(data.message || "Failed to create checkout session");
+    }
+    return res.json();
+}
+
+export async function createOnboardingCheckout(email, tier = "premium") {
+    const res = await fetch(`${API_BASE}/stripe/create-onboarding-checkout`, {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify({ email, tier }),
+    });
+    if (!res.ok) {
+        const data = await res.json();
+        throw new Error(data.message || "Failed to create checkout session");
+    }
+    return res.json();
+}
+
+export async function activateFreeTier() {
+    const headers = await getAuthHeaders();
+    const res = await fetch(`${API_BASE}/stripe/activate-free`, {
+        method: "POST",
+        headers,
+    });
+    if (!res.ok) {
+        const data = await res.json();
+        throw new Error(data.message || "Failed to activate free tier");
+    }
+    return res.json();
+}
+
+export async function verifyCheckoutSession(sessionId) {
+    const headers = await getAuthHeaders();
+    const res = await fetch(`${API_BASE}/stripe/verify-checkout`, {
+        method: "POST",
+        headers: { ...headers, "Content-Type": "application/json" },
+        body: JSON.stringify({ session_id: sessionId }),
+    });
+    if (!res.ok) {
+        const data = await res.json();
+        throw new Error(data.message || "Failed to verify checkout session");
+    }
+    return res.json();
+}
+
+export async function getSubscriptionStatus() {
+    const headers = await getAuthHeaders();
+    const res = await fetch(`${API_BASE}/stripe/subscription-status`, {
+        headers,
+    });
+    if (!res.ok) {
+        const data = await res.json();
+        throw new Error(data.message || "Failed to get subscription status");
+    }
+    return res.json();
+}

frontend/src/components/Input.css

@@ -1,6 +1,6 @@
 .input__label {
   display: block;
-  margin-bottom: 0.4rem;
+  margin: 0.8rem 0rem 0.4rem 0rem;
   font-size: 0.9rem;
 }
 

frontend/src/components/Navbar.css

@@ -8,6 +8,19 @@
   border-bottom: 1px solid var(--color-border-light);
 }
 
+/* ── Left Group: Brand + Links ───────────────────────────── */
+
+.navbar__left {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+}
+
+.navbar__brand-group {
+  display: flex;
+  align-items: center;
+}
+
 .navbar__brand {
   font-weight: 700;
   font-size: 1.4rem;
@@ -38,11 +51,33 @@
   background-color: var(--color-bg-card);
 }
 
+/* ── Right Group: Email + Logout + Hamburger ─────────────── */
+
+.navbar__right {
+  display: flex;
+  align-items: center;
+  gap: 1rem;
+}
+
 .navbar__user {
   font-size: 1.275rem;
   color: #777;
 }
 
+.navbar__user-link {
+  color: var(--color-primary);
+  text-decoration: none;
+  transition: color 0.15s ease;
+}
+
+.navbar__user-link:hover {
+  color: var(--color-primary-hover);
+}
+
+.navbar__user-link--mobile {
+  display: none;
+}
+
 .navbar__logout {
   padding: 0.4rem 1rem;
   font-size: 1.275rem;
@@ -54,3 +89,79 @@
   cursor: pointer;
   transition: all 0.15s ease;
 }
+
+/* ── Hamburger Icon (hidden on desktop) ──────────────────── */
+
+.navbar__hamburger {
+  display: none;
+  flex-direction: column;
+  justify-content: center;
+  gap: 5px;
+  background: none;
+  border: none;
+  cursor: pointer;
+  padding: 4px;
+}
+
+.navbar__hamburger-bar {
+  display: block;
+  width: 28px;
+  height: 3px;
+  background-color: var(--color-brand);
+  border-radius: 2px;
+}
+
+/* ── Responsive: Tablet & below (≤ 768px) ────────────────── */
+
+@media (max-width: 768px) {
+  .navbar {
+    padding: 0.75rem 1rem;
+  }
+
+  .navbar__brand-group {
+    flex-direction: column;
+    align-items: flex-start;
+  }
+
+  .navbar__brand {
+    margin-right: 0;
+    font-size: 1.25rem;
+  }
+
+  .navbar__links {
+    display: none;
+  }
+
+  .navbar__user-link--mobile {
+    display: block;
+    font-size: 0.95rem;
+  }
+
+  .navbar__user-link--desktop {
+    display: none;
+  }
+
+  .navbar__logout {
+    display: none;
+  }
+
+  .navbar__hamburger {
+    display: flex;
+  }
+}
+
+/* ── Responsive: Mobile (≤ 480px) ────────────────────────── */
+
+@media (max-width: 480px) {
+  .navbar {
+    padding: 0.75rem;
+  }
+
+  .navbar__brand {
+    font-size: 1.15rem;
+  }
+
+  .navbar__user-link--mobile {
+    font-size: 0.85rem;
+  }
+}

frontend/src/components/Navbar.jsx

@@ -1,45 +1,71 @@
+import { useState } from "react";
 import { Link, useLocation } from "react-router-dom";
 import { useAuth } from "../contexts/AuthContext";
+import NavPanel from "./navPanel/NavPanel";
 import "./Navbar.css";
 
 const navLinks = [
   { to: "/addresses", label: "Addresses" },
   { to: "/alerts", label: "Configure Alerts" },
-  { to: "/alertevents", label: "Alert Events" },
+  { to: "/alertevents", label: "Alert Event History" },
 ];
 
 export default function Navbar() {
   const { currentUser, logout } = useAuth();
   const location = useLocation();
+  const [isNavPanelOpen, setIsNavPanelOpen] = useState(false);
 
   if (!currentUser) return null;
 
   return (
-    <nav className="navbar">
-      <div className="flex flex--center gap-sm">
-        <span className="navbar__brand">Koin Ping</span>
-        <div className="navbar__links">
-          {navLinks.map(({ to, label }) => {
-            const isActive = location.pathname === to;
-            return (
-              <Link
-                key={to}
-                to={to}
-                className={`navbar__link ${isActive ? "navbar__link--active" : ""}`}
-              >
-                {label}
-              </Link>
-            );
-          })}
+    <>
+      <nav className="navbar">
+        <div className="navbar__left">
+          <div className="navbar__brand-group">
+            <span className="navbar__brand">Koin Ping</span>
+            <Link to="/account" className="navbar__user-link navbar__user-link--mobile">
+              {currentUser.email}
+            </Link>
+          </div>
+          <div className="navbar__links">
+            {navLinks.map(({ to, label }) => {
+              const isActive = location.pathname === to;
+              return (
+                <Link
+                  key={to}
+                  to={to}
+                  className={`navbar__link ${isActive ? "navbar__link--active" : ""}`}
+                >
+                  {label}
+                </Link>
+              );
+            })}
+          </div>
         </div>
-      </div>
 
-      <div className="flex flex--center gap-lg">
-        <span className="navbar__user">{currentUser.email}</span>
-        <button onClick={logout} className="navbar__logout">
-          Logout
-        </button>
-      </div>
-    </nav>
+        <div className="navbar__right">
+          <Link to="/account" className="navbar__user navbar__user-link navbar__user-link--desktop">
+            {currentUser.email}
+          </Link>
+          <button onClick={logout} className="navbar__logout">
+            Logout
+          </button>
+          <button
+            className="navbar__hamburger"
+            onClick={() => setIsNavPanelOpen(true)}
+            aria-label="Open navigation menu"
+          >
+            <span className="navbar__hamburger-bar" />
+            <span className="navbar__hamburger-bar" />
+            <span className="navbar__hamburger-bar" />
+          </button>
+        </div>
+      </nav>
+
+      <NavPanel
+        isOpen={isNavPanelOpen}
+        onClose={() => setIsNavPanelOpen(false)}
+      />
+    </>
   );
 }

frontend/src/components/TierPicker.css

@@ -0,0 +1,120 @@
+.tier-picker {
+  display: grid;
+  grid-template-columns: repeat(3, 1fr);
+  gap: 1rem;
+}
+
+.tier-picker__card {
+  position: relative;
+  display: flex;
+  flex-direction: column;
+  padding: 1.5rem 1.25rem;
+  background-color: var(--color-bg-elevated);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-xl);
+  text-align: center;
+}
+
+.tier-picker__card--highlighted {
+  border-color: var(--color-primary);
+  box-shadow: 0 0 0 1px var(--color-primary);
+}
+
+.tier-picker__card--selected {
+  border-color: var(--color-success);
+  box-shadow: 0 0 0 1px var(--color-success);
+}
+
+.tier-picker__badge {
+  position: absolute;
+  top: -10px;
+  left: 50%;
+  transform: translateX(-50%);
+  background-color: var(--color-primary);
+  color: white;
+  font-size: 0.7rem;
+  font-weight: 700;
+  padding: 2px 12px;
+  border-radius: 10px;
+  white-space: nowrap;
+}
+
+.tier-picker__name {
+  margin-bottom: 0.5rem;
+  font-size: 1.05rem;
+  color: var(--color-text);
+}
+
+.tier-picker__price {
+  margin-bottom: 1.25rem;
+}
+
+.tier-picker__amount {
+  font-size: 2rem;
+  font-weight: 700;
+  color: white;
+}
+
+.tier-picker__period {
+  font-size: 0.85rem;
+  color: var(--color-text-dimmed);
+}
+
+.tier-picker__features {
+  list-style: none;
+  padding: 0;
+  margin: 0 0 1.25rem;
+  text-align: left;
+  flex-grow: 1;
+}
+
+.tier-picker__feature {
+  padding: 0.3rem 0;
+  font-size: 0.82rem;
+  color: var(--color-text-label);
+}
+
+.tier-picker__feature--disabled {
+  color: var(--color-text-dimmed);
+  opacity: 0.55;
+}
+
+.tier-picker__check {
+  color: var(--color-primary);
+  font-weight: bold;
+  margin-right: 0.4rem;
+}
+
+.tier-picker__dash {
+  margin-right: 0.4rem;
+}
+
+.tier-picker__btn {
+  width: 100%;
+  padding: 0.6rem;
+  background-color: var(--color-bg-card);
+  border: 1px solid var(--color-border);
+  color: var(--color-text);
+  cursor: pointer;
+  border-radius: var(--radius-md);
+  font-weight: 600;
+}
+
+.tier-picker__btn:hover {
+  background-color: var(--color-primary);
+  border-color: var(--color-primary);
+}
+
+.tier-picker__btn--selected {
+  background-color: var(--color-success);
+  border-color: var(--color-success);
+  color: white;
+}
+
+@media (max-width: 768px) {
+  .tier-picker {
+    grid-template-columns: 1fr;
+    max-width: 400px;
+    margin: 0 auto;
+  }
+}

frontend/src/components/TierPicker.jsx

@@ -0,0 +1,89 @@
+import "./TierPicker.css";
+
+const TIERS = [
+  {
+    id: "free",
+    name: "Trial Monitoring",
+    price: "$0",
+    period: "",
+    features: [
+      "Monitor 1 blockchain address 24/7",
+      "Configure alerts to fire on trigger events",
+      "1 transaction alert type per trigger (email digest)",
+    ],
+    disabledFeatures: [],
+  },
+  {
+    id: "premium",
+    name: "Premium Monitoring",
+    price: "$1.99",
+    period: "/month",
+    features: [
+      "Monitor 3 blockchain addresses",
+      "Configure two types of rule-based alerts to fire on trigger events for each of the three addresses",
+      "Daily email digest alert",
+      "Real-time Discord alerts",
+      "Real-time Telegram alerts",
+    ],
+    disabledFeatures: [],
+    highlighted: true,
+  },
+  {
+    id: "pro",
+    name: "Professional Monitoring",
+    price: "$11.99",
+    period: "/month",
+    features: [
+      "Monitor unlimited blockchain addresses",
+      "Configure unlimited alert rules to fire on unlimited events on any address",
+      "Daily email digest alert",
+      "Real-time Discord alerts",
+      "Real-time Telegram alerts",
+      "Real-time Slack alerts configurable for multiple Slack groups or channels",
+      "Unlimited transaction alert types per monitored address",
+    ],
+    disabledFeatures: [],
+  },
+];
+
+export default function TierPicker({ onSelect, selectedTier }) {
+  return (
+    <div className="tier-picker">
+      {TIERS.map((tier) => (
+        <div
+          key={tier.id}
+          className={`tier-picker__card${tier.highlighted ? " tier-picker__card--highlighted" : ""}${selectedTier === tier.id ? " tier-picker__card--selected" : ""}`}
+        >
+          {tier.highlighted && (
+            <div className="tier-picker__badge">Most Popular</div>
+          )}
+          <h3 className="tier-picker__name">{tier.name}</h3>
+          <div className="tier-picker__price">
+            <span className="tier-picker__amount">{tier.price}</span>
+            {tier.period && (
+              <span className="tier-picker__period">{tier.period}</span>
+            )}
+          </div>
+          <ul className="tier-picker__features">
+            {tier.features.map((f) => (
+              <li key={f} className="tier-picker__feature">
+                <span className="tier-picker__check">&#10003;</span> {f}
+              </li>
+            ))}
+            {tier.disabledFeatures.map((f) => (
+              <li key={f} className="tier-picker__feature tier-picker__feature--disabled">
+                <span className="tier-picker__dash">&mdash;</span> {f}
+              </li>
+            ))}
+          </ul>
+          <button
+            className={`btn tier-picker__btn${selectedTier === tier.id ? " tier-picker__btn--selected" : ""}`}
+            onClick={() => onSelect(tier.id)}
+          >
+            {selectedTier === tier.id ? "Selected" : "Select"}
+          </button>
+        </div>
+      ))}
+    </div>
+  );
+}

frontend/src/components/UpgradeBanner.css

@@ -0,0 +1,32 @@
+.upgrade-banner {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 1rem;
+  padding: 0.75rem 1rem;
+  margin-bottom: 1rem;
+  border-radius: var(--radius-md);
+  background-color: #3a2e00;
+  border: 1px solid #aa7700;
+  color: #ffcc44;
+}
+
+.upgrade-banner__message {
+  font-size: 0.88rem;
+}
+
+.upgrade-banner__link {
+  background: none;
+  border: 1px solid #aa7700;
+  color: #ffcc44;
+  padding: 0.25rem 0.75rem;
+  border-radius: var(--radius-md);
+  cursor: pointer;
+  font-size: 0.82rem;
+  font-weight: 600;
+  white-space: nowrap;
+}
+
+.upgrade-banner__link:hover {
+  background-color: #4a3800;
+}

frontend/src/components/UpgradeBanner.jsx

@@ -0,0 +1,18 @@
+import { useNavigate } from "react-router-dom";
+import "./UpgradeBanner.css";
+
+export default function UpgradeBanner({ message, linkTo = "/subscribe?upgrade=true" }) {
+  const navigate = useNavigate();
+
+  return (
+    <div className="upgrade-banner">
+      <span className="upgrade-banner__message">{message}</span>
+      <button
+        className="upgrade-banner__link"
+        onClick={() => navigate(linkTo)}
+      >
+        Upgrade
+      </button>
+    </div>
+  );
+}

frontend/src/components/navPanel/NavPanel.css

@@ -0,0 +1,78 @@
+/* ── Overlay Backdrop ─────────────────────────────────────── */
+
+.nav-panel__overlay {
+  position: fixed;
+  inset: 0;
+  background-color: rgba(0, 0, 0, 0.45);
+  opacity: 0;
+  pointer-events: none;
+  transition: opacity 0.3s ease;
+  z-index: 900;
+}
+
+.nav-panel__overlay--visible {
+  opacity: 1;
+  pointer-events: auto;
+}
+
+/* ── Slide-out Panel ─────────────────────────────────────── */
+
+.nav-panel {
+  position: fixed;
+  top: 0;
+  left: 0;
+  width: 260px;
+  height: 100%;
+  background-color: var(--color-bg-elevated);
+  border-right: 1px solid var(--color-border);
+  transform: translateX(-100%);
+  transition: transform 0.3s ease;
+  z-index: 950;
+  display: flex;
+  flex-direction: column;
+  padding: 1.5rem 0;
+}
+
+.nav-panel--open {
+  transform: translateX(0);
+}
+
+/* ── Nav Links ───────────────────────────────────────────── */
+
+.nav-panel__nav {
+  display: flex;
+  flex-direction: column;
+  flex: 1;
+}
+
+.nav-panel__link {
+  padding: 0.9rem 1.5rem;
+  text-decoration: none;
+  font-size: 1.3rem;
+  font-weight: 200;
+  color: var(--color-text-subtle);
+  border-left: 3px solid transparent;
+  transition: background-color 0.15s ease, color 0.15s ease;
+}
+
+.nav-panel__link--active {
+  font-weight: 600;
+  color: var(--color-text);
+  background-color: var(--color-bg-card);
+  border-left-color: var(--color-brand);
+}
+
+/* ── Logout Button ───────────────────────────────────────── */
+
+.nav-panel__logout {
+  margin: 1rem 1.5rem;
+  padding: 0.5rem 1rem;
+  font-size: 1.15rem;
+  font-weight: 400;
+  background-color: transparent;
+  color: var(--color-text-subtle);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-lg);
+  cursor: pointer;
+  transition: all 0.15s ease;
+}

frontend/src/components/navPanel/NavPanel.jsx

@@ -0,0 +1,52 @@
+import { Link, useLocation } from "react-router-dom";
+import { useAuth } from "../../contexts/AuthContext";
+import "./NavPanel.css";
+
+const navLinks = [
+  { to: "/addresses", label: "Addresses" },
+  { to: "/alerts", label: "Configure Alerts" },
+  { to: "/alertevents", label: "Alert Event History" },
+];
+
+export default function NavPanel({ isOpen, onClose }) {
+  const { logout } = useAuth();
+  const location = useLocation();
+
+  const handleNavClick = () => {
+    onClose();
+  };
+
+  const handleLogout = () => {
+    onClose();
+    logout();
+  };
+
+  return (
+    <>
+      <div
+        className={`nav-panel__overlay${isOpen ? " nav-panel__overlay--visible" : ""}`}
+        onClick={onClose}
+      />
+      <aside className={`nav-panel${isOpen ? " nav-panel--open" : ""}`}>
+        <nav className="nav-panel__nav">
+          {navLinks.map(({ to, label }) => {
+            const isActive = location.pathname === to;
+            return (
+              <Link
+                key={to}
+                to={to}
+                className={`nav-panel__link${isActive ? " nav-panel__link--active" : ""}`}
+                onClick={handleNavClick}
+              >
+                {label}
+              </Link>
+            );
+          })}
+        </nav>
+        <button onClick={handleLogout} className="nav-panel__logout">
+          Logout
+        </button>
+      </aside>
+    </>
+  );
+}

frontend/src/contexts/AuthContext.jsx

@@ -1,10 +1,10 @@
 /**
  * AuthContext - Firebase Authentication State Management
  *
- * Provides authentication state and methods throughout the app
+ * Provides authentication state, tier info, and methods throughout the app
  */
 
-import { createContext, useContext, useEffect, useState } from "react";
+import { createContext, useContext, useEffect, useState, useCallback } from "react";
 import {
     createUserWithEmailAndPassword,
     signInWithEmailAndPassword,
@@ -12,9 +12,16 @@ import {
     onAuthStateChanged,
 } from "firebase/auth";
 import { auth } from "../firebase/config";
+import { getAccount } from "../api/account";
 
 const AuthContext = createContext();
 
+const DEFAULT_TIER_LIMITS = {
+    max_addresses: 1,
+    max_alert_types: 1,
+    allowed_channels: ["email"],
+};
+
 /**
  * Hook to access auth context
  * @returns {Object} Auth context value
@@ -28,16 +35,30 @@ export function useAuth() {
 }
 
 /**
- * AuthProvider - Wraps app and provides auth state
+ * AuthProvider - Wraps app and provides auth state + tier info
  */
 export function AuthProvider({ children }) {
     const [currentUser, setCurrentUser] = useState(null);
     const [loading, setLoading] = useState(true);
     const [error, setError] = useState(null);
 
-    /**
-     * Sign up with email and password
-     */
+    const [userTier, setUserTier] = useState("free");
+    const [tierLimits, setTierLimits] = useState(DEFAULT_TIER_LIMITS);
+    const [addressCount, setAddressCount] = useState(0);
+    const [subscriptionStatus, setSubscriptionStatus] = useState("none");
+
+    const refreshAccount = useCallback(async () => {
+        try {
+            const data = await getAccount();
+            setUserTier(data.subscription_tier || "free");
+            setTierLimits(data.tier_limits || DEFAULT_TIER_LIMITS);
+            setAddressCount(data.address_count || 0);
+            setSubscriptionStatus(data.subscription_status || "none");
+        } catch {
+            // account fetch can fail during onboarding before subscription is active
+        }
+    }, []);
+
     async function signup(email, password) {
         try {
             setError(null);
@@ -53,9 +74,6 @@ export function AuthProvider({ children }) {
         }
     }
 
-    /**
-     * Log in with email and password
-     */
     async function login(email, password) {
         try {
             setError(null);
@@ -71,12 +89,13 @@ export function AuthProvider({ children }) {
         }
     }
 
-    /**
-     * Log out current user
-     */
     async function logout() {
         try {
             setError(null);
+            setUserTier("free");
+            setTierLimits(DEFAULT_TIER_LIMITS);
+            setAddressCount(0);
+            setSubscriptionStatus("none");
             await signOut(auth);
         } catch (err) {
             setError(err.message);
@@ -84,18 +103,19 @@ export function AuthProvider({ children }) {
         }
     }
 
-    /**
-     * Listen for auth state changes
-     */
     useEffect(() => {
         const unsubscribe = onAuthStateChanged(auth, (user) => {
             setCurrentUser(user);
             setLoading(false);
+            if (user) {
+                refreshAccount();
+            }
         });
-
-        // Cleanup subscription
         return unsubscribe;
-    }, []);
+    }, [refreshAccount]);
+
+    const isSubscribed =
+        subscriptionStatus === "active" || subscriptionStatus === "trialing";
 
     const value = {
         currentUser,
@@ -104,6 +124,12 @@ export function AuthProvider({ children }) {
         logout,
         error,
         loading,
+        userTier,
+        tierLimits,
+        addressCount,
+        subscriptionStatus,
+        isSubscribed,
+        refreshAccount,
     };
 
     return (

frontend/src/index.css

@@ -356,3 +356,81 @@ button {
   color: white;
   font-size: 0.85rem;
 }
+
+/* ── Responsive Breakpoints ──────────────────────────────── */
+/* Mobile:  <= 480px                                          */
+/* Tablet:  481px – 768px                                     */
+/* Laptop:  769px – 1024px                                    */
+/* Desktop: >= 1025px (default styles above)                  */
+
+/* Laptop & below */
+@media (max-width: 1024px) {
+  .page--wide {
+    max-width: 100%;
+  }
+}
+
+/* Tablet & below */
+@media (max-width: 768px) {
+  html {
+    font-size: 13px;
+  }
+
+  .page {
+    padding: 1.25rem;
+  }
+
+  .btn--lg {
+    padding: 0.6rem 1.2rem;
+  }
+
+  h1 {
+    font-size: 1.75rem;
+  }
+
+  h2 {
+    font-size: 1.4rem;
+  }
+
+  h3 {
+    font-size: 1.15rem;
+  }
+}
+
+/* Tier-locked: greyed out, non-interactive overlay for features above the user's plan */
+.tier-locked {
+  opacity: 0.45;
+  pointer-events: none;
+  filter: grayscale(40%);
+  user-select: none;
+}
+
+/* Mobile */
+@media (max-width: 480px) {
+  html {
+    font-size: 12px;
+  }
+
+  .page {
+    padding: 1rem 0.75rem;
+  }
+
+  .form-control,
+  .form-select {
+    font-size: 0.95rem;
+  }
+
+  .btn {
+    padding: 0.45rem 0.85rem;
+    font-size: 0.95rem;
+  }
+
+  .btn--lg {
+    padding: 0.55rem 1rem;
+    font-size: 1rem;
+  }
+
+  .section {
+    padding: 0.75rem;
+  }
+}

frontend/src/pages/Addresses.jsx

@@ -1,159 +0,0 @@
-import { useState, useEffect } from "react";
-import AddressForm from "../components/AddressForm";
-import { getAddresses, createAddress, deleteAddress, updateAddress } from "../api/addresses";
-import "./Addresses.css";
-
-export default function Addresses() {
-    const [addresses, setAddresses] = useState([]);
-    const [loading, setLoading] = useState(true);
-    const [error, setError] = useState(null);
-    const [editingId, setEditingId] = useState(null);
-    const [editLabel, setEditLabel] = useState("");
-
-    useEffect(() => {
-        async function fetchAddresses() {
-            try {
-                setLoading(true);
-                const data = await getAddresses();
-                setAddresses(data);
-            } catch (err) {
-                setError(err.message);
-                console.error("Failed to fetch addresses:", err);
-            } finally {
-                setLoading(false);
-            }
-        }
-
-        fetchAddresses();
-    }, []);
-
-    async function handleAddressSubmit(data) {
-        try {
-            const newAddress = await createAddress(data);
-            setAddresses((prev) => [...prev, newAddress]);
-            setError(null);
-        } catch (err) {
-            setError(err.message);
-            console.error("Failed to create address:", err);
-        }
-    }
-
-    async function handleDelete(id, label) {
-        const displayName = label || "this address";
-        if (!window.confirm(`Remove "${displayName}"? This will also delete all associated alert rules.`)) {
-            return;
-        }
-        try {
-            await deleteAddress(id);
-            setAddresses((prev) => prev.filter((a) => a.id !== id));
-            setError(null);
-        } catch (err) {
-            setError(err.message);
-            console.error("Failed to delete address:", err);
-        }
-    }
-
-    function handleEditStart(addr) {
-        setEditingId(addr.id);
-        setEditLabel(addr.label ?? "");
-    }
-
-    async function handleEditSave(id) {
-        try {
-            const updated = await updateAddress(id, { label: editLabel || null });
-            setAddresses((prev) => prev.map((a) => (a.id === id ? updated : a)));
-            setEditingId(null);
-            setEditLabel("");
-            setError(null);
-        } catch (err) {
-            setError(err.message);
-            console.error("Failed to update address:", err);
-        }
-    }
-
-    function handleEditCancel() {
-        setEditingId(null);
-        setEditLabel("");
-    }
-
-    return (
-        <div className="page">
-            <h1>Add Addresses to Track</h1>
-
-            <div className="mb-xl">
-                <AddressForm onSubmit={handleAddressSubmit} />
-            </div>
-
-            <div>
-                <h2>Existing Tracked Addresses</h2>
-                {loading && <p>Loading addresses...</p>}
-                {error && <p className="text-error">Error: {error}</p>}
-                {!loading && !error && addresses.length === 0 && (
-                    <p className="text-dimmed">
-                        No addresses tracked yet. Add one above to get started.
-                    </p>
-                )}
-                {addresses.length > 0 && (
-                    <ul className="list-unstyled">
-                        {addresses.map((addr, index) => (
-                            <li key={addr.id || index} className="list-item--card">
-                                <div className="flex flex--between flex--center">
-                                    <div>
-                                        {editingId === addr.id ? (
-                                            <div className="flex flex--center gap-sm mb-sm">
-                                                <input
-                                                    value={editLabel}
-                                                    onChange={(e) => setEditLabel(e.target.value)}
-                                                    placeholder="Label (optional)"
-                                                    className="address__edit-input"
-                                                    onKeyDown={(e) => {
-                                                        if (e.key === "Enter") handleEditSave(addr.id);
-                                                        if (e.key === "Escape") handleEditCancel();
-                                                    }}
-                                                    autoFocus
-                                                />
-                                                <button
-                                                    onClick={() => handleEditSave(addr.id)}
-                                                    className="btn btn--primary btn--sm"
-                                                >
-                                                    Save
-                                                </button>
-                                                <button
-                                                    onClick={handleEditCancel}
-                                                    className="btn btn--ghost btn--sm"
-                                                >
-                                                    Cancel
-                                                </button>
-                                            </div>
-                                        ) : (
-                                            <div className="flex flex--center gap-sm mb-sm">
-                                                <span className="text-bold">
-                                                    {addr.label || "Unlabeled"}
-                                                </span>
-                                                <button
-                                                    onClick={() => handleEditStart(addr)}
-                                                    className="address__edit-link"
-                                                >
-                                                    Edit
-                                                </button>
-                                            </div>
-                                        )}
-                                        <div className="text-mono text-sm text-muted">
-                                            {addr.address}
-                                        </div>
-                                    </div>
-                                    <button
-                                        onClick={() => handleDelete(addr.id, addr.label)}
-                                        className="address__remove"
-                                    >
-                                        Remove
-                                    </button>
-                                </div>
-                            </li>
-                        ))}
-                    </ul>
-                )}
-            </div>
-        </div>
-    );
-}

frontend/src/pages/AlertHistory.jsx

@@ -1,67 +0,0 @@
-import { useState, useEffect } from "react";
-import { getAlertEvents } from "../api/alertEvents";
-import "./AlertHistory.css";
-
-export default function AlertHistory() {
-    const [alertEvents, setAlertEvents] = useState([]);
-    const [loading, setLoading] = useState(true);
-    const [error, setError] = useState(null);
-
-    useEffect(() => {
-        async function fetchAlertEvents() {
-            try {
-                setLoading(true);
-                const data = await getAlertEvents();
-                setAlertEvents(data);
-            } catch (err) {
-                setError(err.message);
-                console.error("Failed to fetch alert events:", err);
-            } finally {
-                setLoading(false);
-            }
-        }
-
-        fetchAlertEvents();
-    }, []);
-
-    if (loading) {
-        return <div className="page">Loading...</div>;
-    }
-
-    if (error) {
-        return (
-            <div className="page text-error">Error: {error}</div>
-        );
-    }
-
-    return (
-        <div className="page">
-            <h1>Recent Alert Events</h1>
-
-            {alertEvents.length === 0 ? (
-                <p className="text-dimmed">No alerts yet</p>
-            ) : (
-                <ul className="list-unstyled">
-                    {alertEvents.map((event) => (
-                        <li key={event.id} className="alert-history__item">
-                            <div className="mb-sm">{event.message}</div>
-                            {event.address_label && (
-                                <div className="text-sm text-dimmed">
-                                    Address: {event.address_label}
-                                </div>
-                            )}
-                            <small className="text-muted">
-                                {formatTimestamp(event.timestamp)}
-                            </small>
-                        </li>
-                    ))}
-                </ul>
-            )}
-        </div>
-    );
-}
-
-function formatTimestamp(timestamp) {
-    const date = new Date(timestamp);
-    return date.toLocaleString();
-}

frontend/src/pages/Alerts.css

@@ -1,63 +0,0 @@
-.alerts-grid {
-  display: grid;
-  grid-template-columns: 1fr 1fr;
-  gap: 2rem;
-  align-items: start;
-}
-
-.alerts__address-info {
-  padding: 1rem;
-  margin-bottom: 2rem;
-  background-color: var(--color-bg-card);
-  border-radius: var(--radius-md);
-  border: 1px solid var(--color-border);
-}
-
-.alerts__toggle-panel {
-  margin-bottom: 1.5rem;
-  padding: 1rem;
-  background-color: var(--color-bg-card);
-  border-radius: var(--radius-md);
-}
-
-.alerts__toggle-label {
-  display: flex;
-  align-items: center;
-  cursor: pointer;
-}
-
-.alerts__toggle-checkbox {
-  margin-right: 0.5rem;
-  width: 18px;
-  height: 18px;
-}
-
-.alerts__toggle-hint {
-  font-size: 0.978rem;
-  color: var(--color-text-dimmed);
-  margin-top: 0.5rem;
-  margin-left: 26px;
-}
-
-.alerts__rule {
-  padding: 1rem;
-  margin-bottom: 0.5rem;
-  border: 1px solid var(--color-border);
-  border-radius: var(--radius-md);
-  background-color: var(--color-bg-card);
-}
-
-.alerts__rule--disabled {
-  opacity: 0.6;
-}
-
-.alerts__email-buttons {
-  display: flex;
-  gap: 0.5rem;
-}
-
-.alerts__save-test {
-  display: flex;
-  gap: 0.75rem;
-  margin-top: 1rem;
-}

frontend/src/pages/Alerts.jsx

@@ -1,522 +0,0 @@
-import { useState, useEffect } from "react";
-import AlertForm from "../components/AlertForm";
-import Button from "../components/Button";
-import Input from "../components/Input";
-import { getAddresses } from "../api/addresses";
-import {
-    getAlerts,
-    createAlert,
-    updateAlertStatus,
-    deleteAlert,
-} from "../api/alerts";
-import {
-    getNotificationConfig,
-    updateNotificationConfig,
-    testNotificationChannels,
-    setupEmail,
-    sendEmailDigest,
-} from "../api/notificationConfig";
-import "./Alerts.css";
-
-export default function Alerts() {
-    const [addresses, setAddresses] = useState([]);
-    const [selectedAddressId, setSelectedAddressId] = useState(null);
-    const [alerts, setAlerts] = useState([]);
-    const [loading, setLoading] = useState(true);
-    const [error, setError] = useState(null);
-
-    const [notificationEnabled, setNotificationEnabled] = useState(false);
-    const [discordWebhookUrl, setDiscordWebhookUrl] = useState("");
-    const [telegramBotToken, setTelegramBotToken] = useState("");
-    const [telegramChatId, setTelegramChatId] = useState("");
-    const [email, setEmail] = useState("");
-    const [slackWebhookUrl, setSlackWebhookUrl] = useState("");
-    const [notificationLoading, setNotificationLoading] = useState(false);
-    const [notificationError, setNotificationError] = useState(null);
-    const [notificationSuccess, setNotificationSuccess] = useState(null);
-    const [testingChannels, setTestingChannels] = useState(false);
-    const [settingUpEmail, setSettingUpEmail] = useState(false);
-    const [sendingDigest, setSendingDigest] = useState(false);
-    const [hasExistingConfig, setHasExistingConfig] = useState(false);
-
-    useEffect(() => {
-        async function fetchData() {
-            try {
-                setLoading(true);
-
-                const addressData = await getAddresses();
-                setAddresses(addressData);
-                if (addressData.length > 0) {
-                    setSelectedAddressId(addressData[0].id);
-                }
-
-                const configData = await getNotificationConfig();
-                setNotificationEnabled(
-                    configData.notification_enabled !== false,
-                );
-                setDiscordWebhookUrl(configData.discord_webhook_url || "");
-                setTelegramBotToken(configData.telegram_bot_token || "");
-                setTelegramChatId(configData.telegram_chat_id || "");
-                setEmail(configData.email || "");
-                setSlackWebhookUrl(configData.slack_webhook_url || "");
-
-                const hasSaved =
-                    !!configData.discord_webhook_url ||
-                    !!configData.telegram_bot_token ||
-                    !!configData.telegram_chat_id ||
-                    !!configData.email ||
-                    !!configData.slack_webhook_url;
-                setHasExistingConfig(hasSaved);
-            } catch (err) {
-                setError(err.message);
-                console.error("Failed to fetch data:", err);
-            } finally {
-                setLoading(false);
-            }
-        }
-
-        fetchData();
-    }, []);
-
-    useEffect(() => {
-        if (!selectedAddressId) {
-            setAlerts([]);
-            return;
-        }
-
-        async function fetchAlerts() {
-            try {
-                const data = await getAlerts(selectedAddressId);
-                setAlerts(data);
-                setError(null);
-            } catch (err) {
-                setError(err.message);
-                console.error("Failed to fetch alerts:", err);
-            }
-        }
-
-        fetchAlerts();
-    }, [selectedAddressId]);
-
-    async function handleAlertSubmit(data) {
-        if (!selectedAddressId) return;
-
-        try {
-            const newAlert = await createAlert(selectedAddressId, data);
-            setAlerts((prev) => [...prev, newAlert]);
-            setError(null);
-        } catch (err) {
-            setError(err.message);
-            console.error("Failed to create alert:", err);
-        }
-    }
-
-    async function handleToggleAlert(alertId, currentStatus) {
-        try {
-            const updated = await updateAlertStatus(alertId, !currentStatus);
-            setAlerts((prev) =>
-                prev.map((alert) => (alert.id === alertId ? updated : alert)),
-            );
-            setError(null);
-        } catch (err) {
-            setError(err.message);
-            console.error("Failed to update alert:", err);
-        }
-    }
-
-    async function handleDeleteAlert(alertId) {
-        try {
-            await deleteAlert(alertId);
-            setAlerts((prev) => prev.filter((alert) => alert.id !== alertId));
-            setError(null);
-        } catch (err) {
-            setError(err.message);
-            console.error("Failed to delete alert:", err);
-        }
-    }
-
-    async function handleSaveNotificationConfig() {
-        if (hasExistingConfig) {
-            const confirmed = window.confirm(
-                "This will overwrite your previously saved notification settings. Continue?",
-            );
-            if (!confirmed) return;
-        }
-
-        try {
-            setNotificationLoading(true);
-            setNotificationError(null);
-            setNotificationSuccess(null);
-
-            const config = {
-                notification_enabled: notificationEnabled,
-                discord_webhook_url: discordWebhookUrl || null,
-                telegram_bot_token: telegramBotToken || null,
-                telegram_chat_id: telegramChatId || null,
-                email: email || null,
-                slack_webhook_url: slackWebhookUrl || null,
-            };
-
-            await updateNotificationConfig(config);
-            setHasExistingConfig(true);
-            setNotificationSuccess("Notification settings saved!");
-            setTimeout(() => setNotificationSuccess(null), 3000);
-        } catch (err) {
-            setNotificationError(err.message);
-            console.error("Failed to save notification config:", err);
-        } finally {
-            setNotificationLoading(false);
-        }
-    }
-
-    async function handleTestChannels() {
-        try {
-            setTestingChannels(true);
-            setNotificationError(null);
-            setNotificationSuccess(null);
-
-            const data = await testNotificationChannels();
-            const results = data.results || [];
-
-            const failed = results.filter((r) => !r.success);
-            const succeeded = results.filter((r) => r.success);
-
-            if (failed.length === 0 && succeeded.length > 0) {
-                setNotificationSuccess(
-                    `Test sent to: ${succeeded.map((r) => r.channel).join(", ")}`,
-                );
-            } else if (failed.length > 0 && succeeded.length > 0) {
-                setNotificationSuccess(
-                    `Sent: ${succeeded.map((r) => r.channel).join(", ")}. Failed: ${failed.map((r) => `${r.channel} (${r.error})`).join(", ")}`,
-                );
-            } else if (failed.length > 0) {
-                setNotificationError(
-                    `Test failed: ${failed.map((r) => `${r.channel} (${r.error})`).join(", ")}`,
-                );
-            }
-
-            setTimeout(() => {
-                setNotificationSuccess(null);
-                setNotificationError(null);
-            }, 6000);
-        } catch (err) {
-            setNotificationError(err.message);
-        } finally {
-            setTestingChannels(false);
-        }
-    }
-
-    async function handleSetupEmail() {
-        try {
-            setSettingUpEmail(true);
-            setNotificationError(null);
-            setNotificationSuccess(null);
-
-            await handleSaveNotificationConfig();
-
-            const result = await setupEmail();
-            setNotificationSuccess(
-                result.message || "Confirmation email sent!",
-            );
-            setTimeout(() => setNotificationSuccess(null), 5000);
-        } catch (err) {
-            setNotificationError(err.message);
-        } finally {
-            setSettingUpEmail(false);
-        }
-    }
-
-    async function handleSendDigest() {
-        try {
-            setSendingDigest(true);
-            setNotificationError(null);
-            setNotificationSuccess(null);
-
-            const result = await sendEmailDigest();
-            setNotificationSuccess(result.message || "Digest email sent!");
-            setTimeout(() => setNotificationSuccess(null), 5000);
-        } catch (err) {
-            setNotificationError(err.message);
-        } finally {
-            setSendingDigest(false);
-        }
-    }
-
-    const selectedAddress = addresses.find((a) => a.id === selectedAddressId);
-
-    if (loading) {
-        return <div className="page">Loading addresses...</div>;
-    }
-
-    if (addresses.length === 0) {
-        return (
-            <div className="page">
-                <p>No addresses tracked yet. Add an address first to create alerts.</p>
-            </div>
-        );
-    }
-
-    return (
-        <div className="page page--wide">
-            <h1 className="mb-xl">Alert Rules & Notifications</h1>
-
-            <div className="alerts-grid">
-                {/* LEFT COLUMN: Alert Rules */}
-                <div>
-                    <h2 className="mt-0">Alert Rules</h2>
-
-                    <div className="mb-xl">
-                        <label className="form-label mb-sm">
-                            <strong>Select Address:</strong>
-                        </label>
-                        <select
-                            value={selectedAddressId || ""}
-                            onChange={(e) =>
-                                setSelectedAddressId(Number(e.target.value))
-                            }
-                            className="form-select"
-                        >
-                            {addresses.map((addr) => (
-                                <option key={addr.id} value={addr.id}>
-                                    {addr.label || "Unlabeled"} - {addr.address}
-                                </option>
-                            ))}
-                        </select>
-                    </div>
-
-                    {selectedAddress && (
-                        <>
-                            <div className="alerts__address-info">
-                                <div className="text-sm text-muted">
-                                    Managing alerts for:
-                                </div>
-                                <div className="text-bold">
-                                    {selectedAddress.label || "Unlabeled"}
-                                </div>
-                                <div className="text-mono text-sm text-muted">
-                                    {selectedAddress.address}
-                                </div>
-                            </div>
-
-                            <div className="mb-xl">
-                                <h3>Create New Alert</h3>
-                                <AlertForm onSubmit={handleAlertSubmit} />
-                            </div>
-
-                            <div>
-                                <h3>Active Alert Rules</h3>
-                                {error && (
-                                    <p className="text-error">Error: {error}</p>
-                                )}
-                                {alerts.length === 0 ? (
-                                    <p className="text-dimmed">
-                                        No alert rules defined yet. Create one above.
-                                    </p>
-                                ) : (
-                                    <ul className="list-unstyled">
-                                        {alerts.map((alert) => (
-                                            <li
-                                                key={alert.id}
-                                                className={`alerts__rule ${!alert.enabled ? "alerts__rule--disabled" : ""}`}
-                                            >
-                                                <div className="flex flex--between">
-                                                    <div>
-                                                        <div className="text-bold mb-sm">
-                                                            {formatAlertType(alert.type)}
-                                                        </div>
-                                                        {alert.threshold && (
-                                                            <div className="text-sm text-muted">
-                                                                Threshold: {alert.threshold} ETH
-                                                            </div>
-                                                        )}
-                                                        <div className="text-xs text-dimmed">
-                                                            Status: {alert.enabled ? "Enabled" : "Disabled"}
-                                                        </div>
-                                                    </div>
-                                                    <div className="flex flex--center gap-sm">
-                                                        <Button
-                                                            onClick={() =>
-                                                                handleToggleAlert(alert.id, alert.enabled)
-                                                            }
-                                                        >
-                                                            {alert.enabled ? "Disable" : "Enable"}
-                                                        </Button>
-                                                        <Button
-                                                            onClick={() => handleDeleteAlert(alert.id)}
-                                                        >
-                                                            Delete
-                                                        </Button>
-                                                    </div>
-                                                </div>
-                                            </li>
-                                        ))}
-                                    </ul>
-                                )}
-                            </div>
-                        </>
-                    )}
-                </div>
-
-                {/* RIGHT COLUMN: Notification Settings */}
-                <div>
-                    <h2 className="mt-0">Notification Settings</h2>
-
-                    {notificationSuccess && (
-                        <div className="alert alert--success">{notificationSuccess}</div>
-                    )}
-
-                    {notificationError && (
-                        <div className="alert alert--error">{notificationError}</div>
-                    )}
-
-                    {/* Master toggle */}
-                    <div className="alerts__toggle-panel">
-                        <label className="alerts__toggle-label">
-                            <input
-                                type="checkbox"
-                                checked={notificationEnabled}
-                                onChange={(e) =>
-                                    setNotificationEnabled(e.target.checked)
-                                }
-                                className="alerts__toggle-checkbox"
-                            />
-                            <span className="text-bold">Enable Notifications</span>
-                        </label>
-                        <div className="alerts__toggle-hint">
-                            Master switch for all notification channels
-                        </div>
-                    </div>
-
-                    {/* All channel settings -- hidden when master toggle is off */}
-                    {notificationEnabled && (
-                        <>
-                            {/* Telegram */}
-                            <div className="section">
-                                <h3 className="mt-0 mb-md">Telegram</h3>
-                                <Input
-                                    label="Bot Token"
-                                    value={telegramBotToken}
-                                    onChange={setTelegramBotToken}
-                                    placeholder="123456789:ABCdefGHIjklMNOpqrSTUvwxYZ"
-                                />
-                                <Input
-                                    label="Chat ID"
-                                    value={telegramChatId}
-                                    onChange={setTelegramChatId}
-                                    placeholder="-1001234567890"
-                                />
-                                <a
-                                    href="https://core.telegram.org/bots#how-do-i-create-a-bot"
-                                    target="_blank"
-                                    rel="noopener noreferrer"
-                                    className="help-link"
-                                >
-                                    How to create a Telegram bot & get your Chat ID
-                                </a>
-                            </div>
-
-                            {/* Email */}
-                            <div className="section">
-                                <h3 className="mt-0 mb-md">Email</h3>
-                                <Input
-                                    label="Email Address"
-                                    type="email"
-                                    value={email}
-                                    onChange={setEmail}
-                                    placeholder="you@example.com"
-                                />
-                                <div className="help-link text-dimmed mb-md">
-                                    Alert notifications and digests will be sent to this address
-                                </div>
-                                <div className="alerts__email-buttons">
-                                    <Button
-                                        onClick={handleSetupEmail}
-                                        disabled={settingUpEmail || !email}
-                                        className="btn--sm"
-                                    >
-                                        {settingUpEmail ? "Setting up..." : "Verify Email"}
-                                    </Button>
-                                    <Button
-                                        onClick={handleSendDigest}
-                                        disabled={sendingDigest || !email}
-                                        variant="secondary"
-                                        className="btn--sm"
-                                    >
-                                        {sendingDigest ? "Sending..." : "Send Digest Now"}
-                                    </Button>
-                                </div>
-                            </div>
-
-                            {/* Discord */}
-                            <div className="section">
-                                <h3 className="mt-0 mb-md">Discord</h3>
-                                <Input
-                                    label="Discord Webhook URL"
-                                    value={discordWebhookUrl}
-                                    onChange={setDiscordWebhookUrl}
-                                    placeholder="https://discord.com/api/webhooks/..."
-                                />
-                                <a
-                                    href="https://support.discord.com/hc/en-us/articles/228383668-Intro-to-Webhooks"
-                                    target="_blank"
-                                    rel="noopener noreferrer"
-                                    className="help-link"
-                                >
-                                    How to get a Discord webhook URL
-                                </a>
-                            </div>
-
-                            {/* Slack */}
-                            <div className="section">
-                                <h3 className="mt-0 mb-md">Slack</h3>
-                                <Input
-                                    label="Slack Webhook URL"
-                                    value={slackWebhookUrl}
-                                    onChange={setSlackWebhookUrl}
-                                    placeholder="https://hooks.slack.com/services/..."
-                                />
-                                <a
-                                    href="https://api.slack.com/messaging/webhooks"
-                                    target="_blank"
-                                    rel="noopener noreferrer"
-                                    className="help-link"
-                                >
-                                    How to set up Slack Incoming Webhooks
-                                </a>
-                            </div>
-
-                            {/* Save & Test buttons */}
-                            <div className="alerts__save-test">
-                                <Button
-                                    onClick={handleSaveNotificationConfig}
-                                    disabled={notificationLoading}
-                                    className="btn--lg"
-                                >
-                                    {notificationLoading ? "Saving..." : "Save Settings"}
-                                </Button>
-                                <Button
-                                    onClick={handleTestChannels}
-                                    disabled={testingChannels}
-                                    variant="success"
-                                    className="btn--lg"
-                                >
-                                    {testingChannels ? "Testing..." : "Test All Channels"}
-                                </Button>
-                            </div>
-                        </>
-                    )}
-                </div>
-            </div>
-        </div>
-    );
-}
-
-function formatAlertType(type) {
-    const labels = {
-        incoming_tx: "Incoming transaction",
-        outgoing_tx: "Outgoing transaction",
-        large_transfer: "Large transfer",
-        balance_below: "Balance below threshold",
-    };
-    return labels[type] || type;
-}

frontend/src/pages/Login.css

@@ -1,64 +0,0 @@
-.login-page {
-  min-height: 100vh;
-  background-image: url(/ping.png);
-  background-size: 67%;
-  background-position: center;
-  background-repeat: no-repeat;
-}
-
-.login-card {
-  max-width: 400px;
-  margin: 20px auto;
-  padding: 2rem;
-  padding-top: 8rem;
-  border: 1px solid var(--color-border-light);
-  border-radius: var(--radius-xl);
-  background-color: rgba(0, 0, 0, 0.75);
-}
-
-.login-heading {
-  margin-bottom: 2rem;
-  text-align: center;
-  position: relative;
-  top: -20px;
-}
-
-.login-brand {
-  color: var(--color-brand);
-}
-
-.login-button {
-  width: 100%;
-  padding: 0.75rem;
-  font-size: 1.2rem;
-  margin-top: 16px;
-  ;
-}
-
-.login-footer {
-  margin-top: 1.5rem;
-  text-align: center;
-}
-
-.login-signup-link {
-  color: var(--color-primary);
-  text-decoration: none;
-}
-
-@keyframes fadeIn {
-  from {
-    opacity: 0;
-  }
-
-  to {
-    opacity: 1;
-  }
-}
-
-.login-form-hidden {
-  opacity: 0;
-}
-
-.login-form-visible {
-  animation: fadeIn 2s ease-in-out forwards;
-}

frontend/src/pages/Onboarding.jsx

@@ -1,644 +0,0 @@
-/**
- * Onboarding Wizard
- *
- * 5-step guided flow: Create Account -> Add Wallet -> Alert Rules -> Notifications -> Done
- */
-
-import { useState, useEffect } from "react";
-import { useNavigate } from "react-router-dom";
-import { useAuth } from "../contexts/AuthContext";
-import { createAddress, getAddresses } from "../api/addresses";
-import { createAlert } from "../api/alerts";
-import {
-    updateNotificationConfig,
-    testNotificationChannels,
-} from "../api/notificationConfig";
-import Input from "../components/Input";
-import Button from "../components/Button";
-import "./Onboarding.css";
-
-const STEPS = [
-    "Create Account",
-    "Add Wallet",
-    "Alert Rules",
-    "Notifications",
-    "Done",
-];
-
-export default function Onboarding() {
-    const { currentUser, signup } = useAuth();
-    const navigate = useNavigate();
-
-    const [step, setStep] = useState(1);
-    const [loading, setLoading] = useState(false);
-    const [error, setError] = useState("");
-    const [skipWarning, setSkipWarning] = useState("");
-    const [testResults, setTestResults] = useState(null);
-    const [testLoading, setTestLoading] = useState(false);
-
-    const [data, setData] = useState({
-        email: "",
-        password: "",
-        confirmPassword: "",
-        walletAddress: "",
-        walletLabel: "",
-        createdAddressId: null,
-        alertIncomingTx: false,
-        alertOutgoingTx: false,
-        alertLargeTransfer: false,
-        largeTransferThreshold: "",
-        alertBalanceBelow: false,
-        balanceBelowThreshold: "",
-        discordWebhookUrl: "",
-        slackWebhookUrl: "",
-        notificationEmail: "",
-        alertsCreated: [],
-        notificationConfigured: false,
-    });
-
-    function set(field, value) {
-        setData((prev) => ({ ...prev, [field]: value }));
-    }
-
-    useEffect(() => {
-        if (!currentUser) return;
-        getAddresses()
-            .then((addresses) => {
-                if (addresses.length > 0) {
-                    navigate("/addresses", { replace: true });
-                }
-            })
-            .catch(() => {});
-    }, [currentUser, navigate]);
-
-    // ── Step handlers ─────────────────────────────────────────────────────────
-
-    async function handleStep1() {
-        setError("");
-        if (!data.email || !data.password || !data.confirmPassword) {
-            setError("Please fill in all fields");
-            return;
-        }
-        if (data.password !== data.confirmPassword) {
-            setError("Passwords do not match");
-            return;
-        }
-        if (data.password.length < 6) {
-            setError("Password must be at least 6 characters");
-            return;
-        }
-        if (!currentUser) {
-            try {
-                setLoading(true);
-                await signup(data.email, data.password);
-            } catch (err) {
-                if (err.code === "auth/email-already-in-use") {
-                    setError("Email already in use. Try logging in instead.");
-                } else if (err.code === "auth/invalid-email") {
-                    setError("Invalid email address");
-                } else if (err.code === "auth/weak-password") {
-                    setError("Password is too weak");
-                } else {
-                    setError("Failed to create account: " + err.message);
-                }
-                setLoading(false);
-                return;
-            } finally {
-                setLoading(false);
-            }
-        }
-        setStep(2);
-    }
-
-    async function handleStep2() {
-        setError("");
-        if (!data.walletAddress) {
-            setError("Please enter a wallet address");
-            return;
-        }
-        if (!/^0x[0-9a-fA-F]{40}$/.test(data.walletAddress)) {
-            setError("Invalid ETH address (must be 0x followed by 40 hex characters)");
-            return;
-        }
-        try {
-            setLoading(true);
-            const created = await createAddress({
-                address: data.walletAddress,
-                label: data.walletLabel || undefined,
-            });
-            set("createdAddressId", created.id);
-            setStep(3);
-        } catch (err) {
-            setError(err.message);
-        } finally {
-            setLoading(false);
-        }
-    }
-
-    async function handleStep3() {
-        setError("");
-        const rules = [];
-        if (data.alertIncomingTx) rules.push({ type: "incoming_tx" });
-        if (data.alertOutgoingTx) rules.push({ type: "outgoing_tx" });
-        if (data.alertLargeTransfer) {
-            if (!data.largeTransferThreshold) {
-                setError("Please enter a threshold for large transfers");
-                return;
-            }
-            rules.push({ type: "large_transfer", threshold: data.largeTransferThreshold });
-        }
-        if (data.alertBalanceBelow) {
-            if (!data.balanceBelowThreshold) {
-                setError("Please enter a threshold for balance below");
-                return;
-            }
-            rules.push({ type: "balance_below", threshold: data.balanceBelowThreshold });
-        }
-
-        if (rules.length === 0) {
-            setStep(4);
-            return;
-        }
-
-        try {
-            setLoading(true);
-            const created = [];
-            for (const rule of rules) {
-                const result = await createAlert(data.createdAddressId, rule);
-                created.push(result);
-            }
-            set("alertsCreated", created);
-            setStep(4);
-        } catch (err) {
-            setError(err.message);
-        } finally {
-            setLoading(false);
-        }
-    }
-
-    async function handleStep4() {
-        setError("");
-        const hasAny =
-            data.discordWebhookUrl || data.slackWebhookUrl || data.notificationEmail;
-        if (!hasAny) {
-            setStep(5);
-            return;
-        }
-        try {
-            setLoading(true);
-            await updateNotificationConfig({
-                notification_enabled: true,
-                discord_webhook_url: data.discordWebhookUrl || undefined,
-                slack_webhook_url: data.slackWebhookUrl || undefined,
-                email: data.notificationEmail || undefined,
-            });
-            set("notificationConfigured", true);
-            setStep(5);
-        } catch (err) {
-            setError(err.message);
-        } finally {
-            setLoading(false);
-        }
-    }
-
-    async function handleTestChannels() {
-        setTestLoading(true);
-        setTestResults(null);
-        try {
-            const results = await testNotificationChannels();
-            setTestResults(results);
-        } catch (err) {
-            setTestResults({ error: err.message });
-        } finally {
-            setTestLoading(false);
-        }
-    }
-
-    // ── Progress bar ──────────────────────────────────────────────────────────
-
-    function ProgressBar() {
-        return (
-            <div className="progress-bar">
-                {STEPS.map((label, i) => {
-                    const stepNum = i + 1;
-                    const done = step > stepNum;
-                    const active = step === stepNum;
-                    const dotClass = done
-                        ? "progress-bar__dot--done"
-                        : active
-                          ? "progress-bar__dot--active"
-                          : "progress-bar__dot--pending";
-
-                    return (
-                        <div key={label} className="progress-bar__step">
-                            {i > 0 && (
-                                <div
-                                    className={`progress-bar__connector ${
-                                        done || active
-                                            ? "progress-bar__connector--active"
-                                            : "progress-bar__connector--inactive"
-                                    }`}
-                                />
-                            )}
-                            <div>
-                                <div className={`progress-bar__dot ${dotClass}`}>
-                                    {done ? "\u2713" : stepNum}
-                                </div>
-                                <div
-                                    className={`progress-bar__label ${
-                                        active
-                                            ? "progress-bar__label--active"
-                                            : "progress-bar__label--inactive"
-                                    }`}
-                                >
-                                    {label}
-                                </div>
-                            </div>
-                        </div>
-                    );
-                })}
-            </div>
-        );
-    }
-
-    // ── Step content ──────────────────────────────────────────────────────────
-
-    function Step1() {
-        return (
-            <>
-                <h2 className="mb-lg">Create your account</h2>
-                <Input
-                    label="Email"
-                    type="email"
-                    value={data.email}
-                    onChange={(v) => set("email", v)}
-                    disabled={loading}
-                    placeholder="you@example.com"
-                />
-                <Input
-                    label="Password"
-                    type="password"
-                    value={data.password}
-                    onChange={(v) => set("password", v)}
-                    disabled={loading}
-                    placeholder="At least 6 characters"
-                />
-                <Input
-                    label="Confirm Password"
-                    type="password"
-                    value={data.confirmPassword}
-                    onChange={(v) => set("confirmPassword", v)}
-                    disabled={loading}
-                    placeholder="Repeat your password"
-                    className="form-field--last"
-                />
-            </>
-        );
-    }
-
-    function Step2() {
-        return (
-            <>
-                <h2 className="mb-sm">Add a wallet address</h2>
-                <p className="onboarding__subtitle">
-                    Enter the Ethereum address you want to monitor.
-                </p>
-                <Input
-                    label="ETH Address"
-                    value={data.walletAddress}
-                    onChange={(v) => set("walletAddress", v)}
-                    disabled={loading}
-                    placeholder="0x..."
-                />
-                <Input
-                    label="Label (optional)"
-                    value={data.walletLabel}
-                    onChange={(v) => set("walletLabel", v)}
-                    disabled={loading}
-                    placeholder="e.g. My main wallet"
-                    className="form-field--last"
-                />
-            </>
-        );
-    }
-
-    function Step3() {
-        return (
-            <>
-                <h2 className="mb-sm">Configure alert rules</h2>
-                <p className="onboarding__subtitle">
-                    Choose which events trigger notifications. You can change these later.
-                </p>
-
-                <CheckboxRow
-                    checked={data.alertIncomingTx}
-                    onChange={(v) => set("alertIncomingTx", v)}
-                    label="Incoming transaction"
-                />
-                <CheckboxRow
-                    checked={data.alertOutgoingTx}
-                    onChange={(v) => set("alertOutgoingTx", v)}
-                    label="Outgoing transaction"
-                />
-                <CheckboxRow
-                    checked={data.alertLargeTransfer}
-                    onChange={(v) => set("alertLargeTransfer", v)}
-                    label="Large transfer"
-                >
-                    {data.alertLargeTransfer && (
-                        <div className="checkbox-row__nested">
-                            <Input
-                                type="number"
-                                label=""
-                                value={data.largeTransferThreshold}
-                                onChange={(v) => set("largeTransferThreshold", v)}
-                                placeholder="Threshold (ETH)"
-                                min="0"
-                                step="0.01"
-                            />
-                        </div>
-                    )}
-                </CheckboxRow>
-                <CheckboxRow
-                    checked={data.alertBalanceBelow}
-                    onChange={(v) => set("alertBalanceBelow", v)}
-                    label="Balance below"
-                >
-                    {data.alertBalanceBelow && (
-                        <div className="checkbox-row__nested">
-                            <Input
-                                type="number"
-                                label=""
-                                value={data.balanceBelowThreshold}
-                                onChange={(v) => set("balanceBelowThreshold", v)}
-                                placeholder="Threshold (ETH)"
-                                min="0"
-                                step="0.01"
-                            />
-                        </div>
-                    )}
-                </CheckboxRow>
-            </>
-        );
-    }
-
-    function Step4() {
-        return (
-            <>
-                <h2 className="mb-sm">Set up notifications</h2>
-                <p className="onboarding__subtitle">
-                    Add at least one channel so you receive alerts. All fields are optional.
-                </p>
-
-                <div className="mb-md">
-                    <label className="form-label">
-                        Discord Webhook URL{" "}
-                        <a
-                            href="https://support.discord.com/hc/en-us/articles/228383668"
-                            target="_blank"
-                            rel="noreferrer"
-                            className="help-link"
-                        >
-                            (how to get one)
-                        </a>
-                    </label>
-                    <Input
-                        label=""
-                        type="url"
-                        value={data.discordWebhookUrl}
-                        onChange={(v) => set("discordWebhookUrl", v)}
-                        disabled={loading}
-                        placeholder="https://discord.com/api/webhooks/..."
-                    />
-                </div>
-
-                <div className="mb-md">
-                    <label className="form-label">
-                        Slack Webhook URL{" "}
-                        <a
-                            href="https://api.slack.com/messaging/webhooks"
-                            target="_blank"
-                            rel="noreferrer"
-                            className="help-link"
-                        >
-                            (how to get one)
-                        </a>
-                    </label>
-                    <Input
-                        label=""
-                        type="url"
-                        value={data.slackWebhookUrl}
-                        onChange={(v) => set("slackWebhookUrl", v)}
-                        disabled={loading}
-                        placeholder="https://hooks.slack.com/services/..."
-                    />
-                </div>
-
-                <Input
-                    label="Email address for alerts"
-                    type="email"
-                    value={data.notificationEmail}
-                    onChange={(v) => set("notificationEmail", v)}
-                    disabled={loading}
-                    placeholder="you@example.com"
-                    className="form-field--last"
-                />
-            </>
-        );
-    }
-
-    function Step5() {
-        const alertCount = data.alertsCreated.length;
-        const hasNotif = data.notificationConfigured;
-
-        return (
-            <>
-                <h2 className="mb-md">You're all set!</h2>
-
-                <div className="onboarding__summary">
-                    <p className="onboarding__summary-title">Summary</p>
-                    <ul className="onboarding__summary-list">
-                        <li>
-                            Wallet address added:{" "}
-                            <span className="text-mono text-white-sm">
-                                {data.walletAddress}
-                            </span>
-                            {data.walletLabel && ` (${data.walletLabel})`}
-                        </li>
-                        <li>
-                            Alert rules configured:{" "}
-                            <span className="text-white">
-                                {alertCount > 0 ? `${alertCount} rule${alertCount !== 1 ? "s" : ""}` : "None (skipped)"}
-                            </span>
-                        </li>
-                        <li>
-                            Notification channels:{" "}
-                            <span className="text-white">
-                                {hasNotif ? "Configured" : "Not set up (skipped)"}
-                            </span>
-                        </li>
-                    </ul>
-                </div>
-
-                {hasNotif && (
-                    <div className="mb-lg">
-                        <Button
-                            onClick={handleTestChannels}
-                            disabled={testLoading}
-                            variant="ghost"
-                        >
-                            {testLoading ? "Testing..." : "Test All Channels"}
-                        </Button>
-
-                        {testResults && (
-                            <div className="mt-md">
-                                {testResults.error ? (
-                                    <p className="text-error">{testResults.error}</p>
-                                ) : (
-                                    <ul className="list-unstyled">
-                                        {Object.entries(testResults).map(([channel, result]) => (
-                                            <li
-                                                key={channel}
-                                                className={`test-result ${result.success ? "test-result--success" : "test-result--failure"}`}
-                                            >
-                                                {result.success ? "\u2713" : "\u2717"} {channel}:{" "}
-                                                {result.message || (result.success ? "OK" : "Failed")}
-                                            </li>
-                                        ))}
-                                    </ul>
-                                )}
-                            </div>
-                        )}
-                    </div>
-                )}
-
-                <Button onClick={() => navigate("/addresses")} className="btn--lg text-bold">
-                    Go to Dashboard →
-                </Button>
-            </>
-        );
-    }
-
-    // ── Shared helpers ────────────────────────────────────────────────────────
-
-    function CheckboxRow({ checked, onChange, label, children }) {
-        return (
-            <div className="checkbox-row">
-                <label className="checkbox-row__label">
-                    <input
-                        type="checkbox"
-                        checked={checked}
-                        onChange={(e) => onChange(e.target.checked)}
-                        className="checkbox-row__input"
-                    />
-                    {label}
-                </label>
-                {children}
-            </div>
-        );
-    }
-
-    // ── Footer navigation ─────────────────────────────────────────────────────
-
-    function Footer() {
-        if (step === 5) return null;
-
-        const canSkip = step === 3 || step === 4;
-        const canBack = step > 1;
-
-        async function handleNext() {
-            setSkipWarning("");
-            if (step === 1) await handleStep1();
-            else if (step === 2) await handleStep2();
-            else if (step === 3) await handleStep3();
-            else if (step === 4) await handleStep4();
-        }
-
-        function handleSkip() {
-            setError("");
-            setSkipWarning("");
-            setStep((s) => s + 1);
-        }
-
-        function handleBack() {
-            setError("");
-            setSkipWarning("");
-            setStep((s) => s - 1);
-        }
-
-        return (
-            <div className="onboarding__footer">
-                <div>
-                    {canBack && (
-                        <Button
-                            onClick={handleBack}
-                            disabled={loading}
-                            variant="ghost"
-                        >
-                            ← Back
-                        </Button>
-                    )}
-                </div>
-
-                <div className="flex gap-md">
-                    {canSkip && (
-                        <Button
-                            onClick={handleSkip}
-                            disabled={loading}
-                            variant="ghost"
-                        >
-                            Skip for now
-                        </Button>
-                    )}
-                    <Button
-                        onClick={handleNext}
-                        disabled={loading}
-                        className="text-bold"
-                    >
-                        {loading ? "Please wait..." : step === 4 ? "Finish" : "Next →"}
-                    </Button>
-                </div>
-            </div>
-        );
-    }
-
-    // ── Render ────────────────────────────────────────────────────────────────
-
-    const stepContent = {
-        1: <Step1 />,
-        2: <Step2 />,
-        3: <Step3 />,
-        4: <Step4 />,
-        5: <Step5 />,
-    };
-
-    return (
-        <div className="onboarding">
-            <div className="onboarding__container">
-                <h1 className="onboarding__title">Koin Ping</h1>
-
-                <ProgressBar />
-
-                {error && (
-                    <div className="alert alert--error">{error}</div>
-                )}
-
-                {skipWarning && (
-                    <div className="alert alert--warning">{skipWarning}</div>
-                )}
-
-                <div className="onboarding__card">
-                    {stepContent[step]}
-                    <Footer />
-                </div>
-
-                {step === 1 && (
-                    <p className="onboarding__login-link">
-                        Already have an account?{" "}
-                        <a href="/login">Log in here</a>
-                    </p>
-                )}
-            </div>
-        </div>
-    );
-}

frontend/src/pages/Signup.jsx

@@ -1,5 +1,5 @@
 import { Navigate } from "react-router-dom";
 
 export default function Signup() {
-    return <Navigate to="/onboarding" replace />;
+    return <Navigate to="/subscribe" replace />;
 }

frontend/src/pages/addresses/Addresses.css

@@ -28,3 +28,13 @@
   margin-left: 1rem;
   flex-shrink: 0;
 }
+
+/* ── Addresses Responsive ────────────────────────────────── */
+
+@media (max-width: 480px) {
+  .address__remove {
+    margin-left: 0.5rem;
+    padding: 0.25rem 0.5rem;
+    font-size: 0.8rem;
+  }
+}

frontend/src/pages/addresses/Addresses.jsx

@@ -0,0 +1,174 @@
+import { useState, useEffect } from "react";
+import { useAuth } from "../../contexts/AuthContext";
+import AddressForm from "../../components/AddressForm";
+import UpgradeBanner from "../../components/UpgradeBanner";
+import { getAddresses, createAddress, deleteAddress, updateAddress } from "../../api/addresses";
+import "./Addresses.css";
+
+export default function Addresses() {
+  const { tierLimits, refreshAccount } = useAuth();
+  const [addresses, setAddresses] = useState([]);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState(null);
+  const [editingId, setEditingId] = useState(null);
+  const [editLabel, setEditLabel] = useState("");
+
+  const maxAddresses = tierLimits.max_addresses;
+  const isUnlimited = maxAddresses === -1;
+  const atLimit = !isUnlimited && addresses.length >= maxAddresses;
+
+  useEffect(() => {
+    async function fetchAddresses() {
+      try {
+        setLoading(true);
+        const data = await getAddresses();
+        setAddresses(data);
+      } catch (err) {
+        setError(err.message);
+        console.error("Failed to fetch addresses:", err);
+      } finally {
+        setLoading(false);
+      }
+    }
+
+    fetchAddresses();
+  }, []);
+
+  async function handleAddressSubmit(data) {
+    try {
+      const newAddress = await createAddress(data);
+      setAddresses((prev) => [...prev, newAddress]);
+      setError(null);
+      refreshAccount();
+    } catch (err) {
+      setError(err.message);
+      console.error("Failed to create address:", err);
+    }
+  }
+
+  async function handleDelete(id, label) {
+    const displayName = label || "this address";
+    if (!window.confirm(`Remove "${displayName}"? This will also delete all associated alert rules.`)) {
+      return;
+    }
+    try {
+      await deleteAddress(id);
+      setAddresses((prev) => prev.filter((a) => a.id !== id));
+      setError(null);
+      refreshAccount();
+    } catch (err) {
+      setError(err.message);
+      console.error("Failed to delete address:", err);
+    }
+  }
+
+  function handleEditStart(addr) {
+    setEditingId(addr.id);
+    setEditLabel(addr.label ?? "");
+  }
+
+  async function handleEditSave(id) {
+    try {
+      const updated = await updateAddress(id, { label: editLabel || null });
+      setAddresses((prev) => prev.map((a) => (a.id === id ? updated : a)));
+      setEditingId(null);
+      setEditLabel("");
+      setError(null);
+    } catch (err) {
+      setError(err.message);
+      console.error("Failed to update address:", err);
+    }
+  }
+
+  function handleEditCancel() {
+    setEditingId(null);
+    setEditLabel("");
+  }
+
+  return (
+    <div className="page">
+      <h1>Add Addresses to Track</h1>
+
+      {atLimit && (
+        <UpgradeBanner
+          message={`Your plan allows ${maxAddresses} address${maxAddresses !== 1 ? "es" : ""}. Upgrade to track more.`}
+        />
+      )}
+
+      <div className={`mb-xl${atLimit ? " tier-locked" : ""}`}>
+        <AddressForm onSubmit={handleAddressSubmit} />
+      </div>
+
+      <div>
+        <h2>Existing Tracked Addresses</h2>
+        {loading && <p>Loading addresses...</p>}
+        {error && <p className="text-error">Error: {error}</p>}
+        {!loading && !error && addresses.length === 0 && (
+          <p className="text-dimmed">
+            No addresses tracked yet. Add one above to get started.
+          </p>
+        )}
+        {addresses.length > 0 && (
+          <ul className="list-unstyled">
+            {addresses.map((addr, index) => (
+              <li key={addr.id || index} className="list-item--card">
+                <div className="flex flex--between flex--center">
+                  <div>
+                    {editingId === addr.id ? (
+                      <div className="flex flex--center gap-sm mb-sm">
+                        <input
+                          value={editLabel}
+                          onChange={(e) => setEditLabel(e.target.value)}
+                          placeholder="Label (optional)"
+                          className="address__edit-input"
+                          onKeyDown={(e) => {
+                            if (e.key === "Enter") handleEditSave(addr.id);
+                            if (e.key === "Escape") handleEditCancel();
+                          }}
+                          autoFocus
+                        />
+                        <button
+                          onClick={() => handleEditSave(addr.id)}
+                          className="btn btn--primary btn--sm"
+                        >
+                          Save
+                        </button>
+                        <button
+                          onClick={handleEditCancel}
+                          className="btn btn--ghost btn--sm"
+                        >
+                          Cancel
+                        </button>
+                      </div>
+                    ) : (
+                      <div className="flex flex--center gap-sm mb-sm">
+                        <span className="text-bold">
+                          {addr.label || "Unlabeled"}
+                        </span>
+                        <button
+                          onClick={() => handleEditStart(addr)}
+                          className="address__edit-link"
+                        >
+                          Edit
+                        </button>
+                      </div>
+                    )}
+                    <div className="text-mono text-sm text-muted">
+                      {addr.address}
+                    </div>
+                  </div>
+                  <button
+                    onClick={() => handleDelete(addr.id, addr.label)}
+                    className="address__remove"
+                  >
+                    Remove
+                  </button>
+                </div>
+              </li>
+            ))}
+          </ul>
+        )}
+      </div>
+    </div>
+  );
+}

frontend/src/pages/alertHistory/AlertHistory.jsx

@@ -0,0 +1,67 @@
+import { useState, useEffect } from "react";
+import { getAlertEvents } from "../../api/alertEvents";
+import "./AlertHistory.css";
+
+export default function AlertHistory() {
+  const [alertEvents, setAlertEvents] = useState([]);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState(null);
+
+  useEffect(() => {
+    async function fetchAlertEvents() {
+      try {
+        setLoading(true);
+        const data = await getAlertEvents();
+        setAlertEvents(data);
+      } catch (err) {
+        setError(err.message);
+        console.error("Failed to fetch alert events:", err);
+      } finally {
+        setLoading(false);
+      }
+    }
+
+    fetchAlertEvents();
+  }, []);
+
+  if (loading) {
+    return <div className="page">Loading...</div>;
+  }
+
+  if (error) {
+    return (
+      <div className="page text-error">Error: {error}</div>
+    );
+  }
+
+  return (
+    <div className="page">
+      <h1>Recent Alert Events</h1>
+
+      {alertEvents.length === 0 ? (
+        <p className="text-dimmed">No alerts yet</p>
+      ) : (
+        <ul className="list-unstyled">
+          {alertEvents.map((event) => (
+            <li key={event.id} className="alert-history__item">
+              <div className="mb-sm">{event.message}</div>
+              {event.address_label && (
+                <div className="text-sm text-dimmed">
+                  Address: {event.address_label}
+                </div>
+              )}
+              <small className="text-muted">
+                {formatTimestamp(event.timestamp)}
+              </small>
+            </li>
+          ))}
+        </ul>
+      )}
+    </div>
+  );
+}
+
+function formatTimestamp(timestamp) {
+  const date = new Date(timestamp);
+  return date.toLocaleString();
+}

frontend/src/pages/alerts/Alerts.css

@@ -0,0 +1,191 @@
+.alerts-grid {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 2rem;
+  align-items: start;
+}
+
+.alerts__address-info {
+  padding: 1rem;
+  margin-bottom: 2rem;
+  background-color: var(--color-bg-card);
+  border-radius: var(--radius-md);
+  border: 1px solid var(--color-border);
+}
+
+.alerts__toggle-panel {
+  margin-bottom: 1.5rem;
+  padding: 1rem;
+  background-color: var(--color-bg-card);
+  border-radius: var(--radius-md);
+}
+
+.alerts__toggle-label {
+  display: flex;
+  align-items: center;
+  cursor: pointer;
+}
+
+.alerts__toggle-checkbox {
+  margin-right: 0.5rem;
+  width: 18px;
+  height: 18px;
+}
+
+.alerts__toggle-hint {
+  font-size: 0.978rem;
+  color: var(--color-text-dimmed);
+  margin-top: 0.5rem;
+  margin-left: 26px;
+}
+
+.alerts__rule {
+  padding: 1rem;
+  margin-bottom: 0.5rem;
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-md);
+  background-color: var(--color-bg-card);
+}
+
+.alerts__rule--disabled {
+  opacity: 0.6;
+}
+
+.alerts__accordion-toggle {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  margin-top: 0.75rem;
+  padding: 0.5rem 0 0;
+  border-top: 1px solid var(--color-border);
+  cursor: pointer;
+  font-size: 0.85rem;
+  color: var(--color-text-muted);
+  background: none;
+  border-left: none;
+  border-right: none;
+  border-bottom: none;
+  width: 100%;
+  text-align: left;
+}
+
+.alerts__accordion-toggle:hover {
+  color: var(--color-text);
+}
+
+.alerts__accordion-chevron {
+  display: inline-block;
+  transition: transform 0.2s ease;
+  font-size: 0.7rem;
+}
+
+.alerts__accordion-chevron--open {
+  transform: rotate(90deg);
+}
+
+.alerts__accordion-panel {
+  overflow: hidden;
+  max-height: 0;
+  opacity: 0;
+  transition: max-height 0.25s ease, opacity 0.2s ease, padding 0.25s ease;
+  padding: 0 0.25rem;
+}
+
+.alerts__accordion-panel--open {
+  max-height: 200px;
+  opacity: 1;
+  padding: 0.75rem 0.25rem 0.25rem;
+}
+
+.alerts__threshold-inputs {
+  display: flex;
+  gap: 1rem;
+  align-items: flex-end;
+}
+
+.alerts__threshold-inputs .form-field {
+  flex: 1;
+  margin-bottom: 0;
+}
+
+.alerts__threshold-actions {
+  display: flex;
+  gap: 0.5rem;
+  margin-top: 0.5rem;
+}
+
+.alerts__email-buttons {
+  display: flex;
+  gap: 0.5rem;
+}
+
+.alerts__save-test {
+  display: flex;
+  gap: 0.75rem;
+  margin-top: 1rem;
+}
+
+/* Locked / disabled notification channel */
+.alerts__channel-locked {
+  opacity: 0.55;
+  position: relative;
+}
+
+.alerts__channel-locked .upgrade-banner {
+  opacity: 1;
+}
+
+.alerts__channel-locked input {
+  pointer-events: none;
+}
+
+/* ── Alerts Page Responsive ──────────────────────────────── */
+
+/* Laptop: tighten the gap */
+@media (max-width: 1024px) {
+  .alerts-grid {
+    gap: 1.5rem;
+  }
+}
+
+/* Tablet & below: collapse to single column */
+@media (max-width: 768px) {
+  .alerts-grid {
+    grid-template-columns: 1fr;
+    gap: 2.5rem;
+  }
+}
+
+/* Mobile: compact spacing */
+@media (max-width: 480px) {
+  .alerts-grid {
+    gap: 2rem;
+  }
+
+  .alerts__address-info {
+    padding: 0.75rem;
+    margin-bottom: 1.25rem;
+  }
+
+  .alerts__rule {
+    padding: 0.75rem;
+  }
+
+  .alerts__rule .flex--between {
+    flex-direction: column;
+    gap: 0.75rem;
+  }
+
+  .alerts__save-test {
+    flex-direction: column;
+  }
+
+  .alerts__save-test .btn--lg {
+    width: 100%;
+    text-align: center;
+  }
+
+  .alerts__email-buttons {
+    flex-direction: column;
+  }
+}

frontend/src/pages/alerts/Alerts.jsx

@@ -0,0 +1,709 @@
+import { useState, useEffect } from "react";
+import { useAuth } from "../../contexts/AuthContext";
+import AlertForm from "../../components/AlertForm";
+import Button from "../../components/Button";
+import Input from "../../components/Input";
+import UpgradeBanner from "../../components/UpgradeBanner";
+import { getAddresses } from "../../api/addresses";
+import {
+  getAlerts,
+  createAlert,
+  updateAlertStatus,
+  updateAlertThresholds,
+  deleteAlert,
+} from "../../api/alerts";
+import {
+  getNotificationConfig,
+  updateNotificationConfig,
+  testNotificationChannels,
+  setupEmail,
+  sendEmailDigest,
+} from "../../api/notificationConfig";
+import "./Alerts.css";
+
+export default function Alerts() {
+  const { tierLimits, userTier } = useAuth();
+
+  const [addresses, setAddresses] = useState([]);
+  const [selectedAddressId, setSelectedAddressId] = useState(null);
+  const [alerts, setAlerts] = useState([]);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState(null);
+
+  const [notificationEnabled, setNotificationEnabled] = useState(false);
+  const [discordWebhookUrl, setDiscordWebhookUrl] = useState("");
+  const [telegramBotToken, setTelegramBotToken] = useState("");
+  const [telegramChatId, setTelegramChatId] = useState("");
+  const [email, setEmail] = useState("");
+  const [slackWebhookUrl, setSlackWebhookUrl] = useState("");
+  const [notificationLoading, setNotificationLoading] = useState(false);
+  const [notificationError, setNotificationError] = useState(null);
+  const [notificationSuccess, setNotificationSuccess] = useState(null);
+  const [testingChannels, setTestingChannels] = useState(false);
+  const [settingUpEmail, setSettingUpEmail] = useState(false);
+  const [sendingDigest, setSendingDigest] = useState(false);
+  const [hasExistingConfig, setHasExistingConfig] = useState(false);
+
+  const [openAccordions, setOpenAccordions] = useState({});
+  const [thresholdEdits, setThresholdEdits] = useState({});
+
+  const allowedChannels = tierLimits.allowed_channels || ["email"];
+  const canTelegram = allowedChannels.includes("telegram");
+  const canDiscord = allowedChannels.includes("discord");
+  const canSlack = allowedChannels.includes("slack");
+
+  const maxAlertTypes = tierLimits.max_alert_types;
+  const isUnlimitedAlerts = maxAlertTypes === -1;
+
+  function distinctAlertTypeCount() {
+    const types = new Set(alerts.map((a) => a.type));
+    return types.size;
+  }
+
+  const atAlertLimit = !isUnlimitedAlerts && distinctAlertTypeCount() >= maxAlertTypes;
+
+  function toggleAccordion(alertId) {
+    setOpenAccordions((prev) => ({ ...prev, [alertId]: !prev[alertId] }));
+  }
+
+  function getThresholdEdit(alert) {
+    if (thresholdEdits[alert.id]) return thresholdEdits[alert.id];
+    return {
+      minimum: alert.minimum != null ? String(alert.minimum) : "",
+      maximum: alert.maximum != null ? String(alert.maximum) : "",
+    };
+  }
+
+  function setThresholdEdit(alertId, field, value) {
+    setThresholdEdits((prev) => {
+      const current = prev[alertId] || getThresholdEditForAlert(alertId);
+      return { ...prev, [alertId]: { ...current, [field]: value } };
+    });
+  }
+
+  function getThresholdEditForAlert(alertId) {
+    const alert = alerts.find((a) => a.id === alertId);
+    return {
+      minimum: alert?.minimum != null ? String(alert.minimum) : "",
+      maximum: alert?.maximum != null ? String(alert.maximum) : "",
+    };
+  }
+
+  async function handleSaveThresholds(alertId) {
+    const edit = thresholdEdits[alertId];
+    if (!edit) return;
+
+    const min = edit.minimum.trim() === "" ? null : Number(edit.minimum);
+    const max = edit.maximum.trim() === "" ? null : Number(edit.maximum);
+
+    if (min !== null && isNaN(min)) return;
+    if (max !== null && isNaN(max)) return;
+    if (min !== null && max !== null && min > max) return;
+
+    try {
+      const updated = await updateAlertThresholds(alertId, min, max);
+      setAlerts((prev) =>
+        prev.map((a) => (a.id === alertId ? updated : a)),
+      );
+      setThresholdEdits((prev) => {
+        const next = { ...prev };
+        delete next[alertId];
+        return next;
+      });
+      setError(null);
+    } catch (err) {
+      setError(err.message);
+      console.error("Failed to update thresholds:", err);
+    }
+  }
+
+  useEffect(() => {
+    async function fetchData() {
+      try {
+        setLoading(true);
+
+        const addressData = await getAddresses();
+        setAddresses(addressData);
+        if (addressData.length > 0) {
+          setSelectedAddressId(addressData[0].id);
+        }
+
+        const configData = await getNotificationConfig();
+        setNotificationEnabled(
+          configData.notification_enabled !== false,
+        );
+        setDiscordWebhookUrl(configData.discord_webhook_url || "");
+        setTelegramBotToken(configData.telegram_bot_token || "");
+        setTelegramChatId(configData.telegram_chat_id || "");
+        setEmail(configData.email || "");
+        setSlackWebhookUrl(configData.slack_webhook_url || "");
+
+        const hasSaved =
+          !!configData.discord_webhook_url ||
+          !!configData.telegram_bot_token ||
+          !!configData.telegram_chat_id ||
+          !!configData.email ||
+          !!configData.slack_webhook_url;
+        setHasExistingConfig(hasSaved);
+      } catch (err) {
+        setError(err.message);
+        console.error("Failed to fetch data:", err);
+      } finally {
+        setLoading(false);
+      }
+    }
+
+    fetchData();
+  }, []);
+
+  useEffect(() => {
+    if (!selectedAddressId) {
+      setAlerts([]);
+      return;
+    }
+
+    async function fetchAlerts() {
+      try {
+        const data = await getAlerts(selectedAddressId);
+        setAlerts(data);
+        setError(null);
+      } catch (err) {
+        setError(err.message);
+        console.error("Failed to fetch alerts:", err);
+      }
+    }
+
+    fetchAlerts();
+  }, [selectedAddressId]);
+
+  async function handleAlertSubmit(data) {
+    if (!selectedAddressId) return;
+
+    try {
+      const newAlert = await createAlert(selectedAddressId, data);
+      setAlerts((prev) => [...prev, newAlert]);
+      setError(null);
+    } catch (err) {
+      setError(err.message);
+      console.error("Failed to create alert:", err);
+    }
+  }
+
+  async function handleToggleAlert(alertId, currentStatus) {
+    try {
+      const updated = await updateAlertStatus(alertId, !currentStatus);
+      setAlerts((prev) =>
+        prev.map((alert) => (alert.id === alertId ? updated : alert)),
+      );
+      setError(null);
+    } catch (err) {
+      setError(err.message);
+      console.error("Failed to update alert:", err);
+    }
+  }
+
+  async function handleDeleteAlert(alertId) {
+    try {
+      await deleteAlert(alertId);
+      setAlerts((prev) => prev.filter((alert) => alert.id !== alertId));
+      setError(null);
+    } catch (err) {
+      setError(err.message);
+      console.error("Failed to delete alert:", err);
+    }
+  }
+
+  async function handleSaveNotificationConfig() {
+    if (hasExistingConfig) {
+      const confirmed = window.confirm(
+        "This will overwrite your previously saved notification settings. Continue?",
+      );
+      if (!confirmed) return;
+    }
+
+    try {
+      setNotificationLoading(true);
+      setNotificationError(null);
+      setNotificationSuccess(null);
+
+      const config = {
+        notification_enabled: notificationEnabled,
+        discord_webhook_url: canDiscord ? (discordWebhookUrl || null) : null,
+        telegram_bot_token: canTelegram ? (telegramBotToken || null) : null,
+        telegram_chat_id: canTelegram ? (telegramChatId || null) : null,
+        email: email || null,
+        slack_webhook_url: canSlack ? (slackWebhookUrl || null) : null,
+      };
+
+      await updateNotificationConfig(config);
+      setHasExistingConfig(true);
+      setNotificationSuccess("Notification settings saved!");
+      setTimeout(() => setNotificationSuccess(null), 3000);
+    } catch (err) {
+      setNotificationError(err.message);
+      console.error("Failed to save notification config:", err);
+    } finally {
+      setNotificationLoading(false);
+    }
+  }
+
+  async function handleTestChannels() {
+    try {
+      setTestingChannels(true);
+      setNotificationError(null);
+      setNotificationSuccess(null);
+
+      const data = await testNotificationChannels();
+      const results = data.results || [];
+
+      const failed = results.filter((r) => !r.success);
+      const succeeded = results.filter((r) => r.success);
+
+      if (failed.length === 0 && succeeded.length > 0) {
+        setNotificationSuccess(
+          `Test sent to: ${succeeded.map((r) => r.channel).join(", ")}`,
+        );
+      } else if (failed.length > 0 && succeeded.length > 0) {
+        setNotificationSuccess(
+          `Sent: ${succeeded.map((r) => r.channel).join(", ")}. Failed: ${failed.map((r) => `${r.channel} (${r.error})`).join(", ")}`,
+        );
+      } else if (failed.length > 0) {
+        setNotificationError(
+          `Test failed: ${failed.map((r) => `${r.channel} (${r.error})`).join(", ")}`,
+        );
+      }
+
+      setTimeout(() => {
+        setNotificationSuccess(null);
+        setNotificationError(null);
+      }, 6000);
+    } catch (err) {
+      setNotificationError(err.message);
+    } finally {
+      setTestingChannels(false);
+    }
+  }
+
+  async function handleSetupEmail() {
+    try {
+      setSettingUpEmail(true);
+      setNotificationError(null);
+      setNotificationSuccess(null);
+
+      await handleSaveNotificationConfig();
+
+      const result = await setupEmail();
+      setNotificationSuccess(
+        result.message || "Confirmation email sent!",
+      );
+      setTimeout(() => setNotificationSuccess(null), 5000);
+    } catch (err) {
+      setNotificationError(err.message);
+    } finally {
+      setSettingUpEmail(false);
+    }
+  }
+
+  async function handleSendDigest() {
+    try {
+      setSendingDigest(true);
+      setNotificationError(null);
+      setNotificationSuccess(null);
+
+      const result = await sendEmailDigest();
+      setNotificationSuccess(result.message || "Digest email sent!");
+      setTimeout(() => setNotificationSuccess(null), 5000);
+    } catch (err) {
+      setNotificationError(err.message);
+    } finally {
+      setSendingDigest(false);
+    }
+  }
+
+  const selectedAddress = addresses.find((a) => a.id === selectedAddressId);
+
+  if (loading) {
+    return <div className="page">Loading addresses...</div>;
+  }
+
+  if (addresses.length === 0) {
+    return (
+      <div className="page">
+        <p>No addresses tracked yet. Add an address first to create alerts.</p>
+      </div>
+    );
+  }
+
+  return (
+    <div className="page page--wide">
+      <h1 className="mb-xl">Alert Rules & Notifications</h1>
+
+      <div className="alerts-grid">
+        {/* LEFT COLUMN: Alert Rules */}
+        <div>
+          <h2 className="mt-0">Alert Rules</h2>
+
+          <div className="mb-xl">
+            <label className="form-label mb-sm">
+              <strong>Select Address:</strong>
+            </label>
+            <select
+              value={selectedAddressId || ""}
+              onChange={(e) =>
+                setSelectedAddressId(Number(e.target.value))
+              }
+              className="form-select"
+            >
+              {addresses.map((addr) => (
+                <option key={addr.id} value={addr.id}>
+                  {addr.label || "Unlabeled"} - {addr.address}
+                </option>
+              ))}
+            </select>
+          </div>
+
+          {selectedAddress && (
+            <>
+              <div className="alerts__address-info">
+                <div className="text-sm text-muted">
+                  Managing alerts for:
+                </div>
+                <div className="text-bold">
+                  {selectedAddress.label || "Unlabeled"}
+                </div>
+                <div className="text-mono text-sm text-muted">
+                  {selectedAddress.address}
+                </div>
+              </div>
+
+              {atAlertLimit && userTier !== "pro" && (
+                <UpgradeBanner
+                  message={`Your ${userTier} plan allows ${maxAlertTypes} alert type${maxAlertTypes !== 1 ? "s" : ""} per address. Upgrade for more.`}
+                />
+              )}
+
+              <div className={`mb-xl${atAlertLimit ? " tier-locked" : ""}`}>
+                <h3>Create New Alert</h3>
+                <AlertForm onSubmit={handleAlertSubmit} />
+              </div>
+
+              <div>
+                <h3>Active Alert Rules</h3>
+                {error && (
+                  <p className="text-error">Error: {error}</p>
+                )}
+                {alerts.length === 0 ? (
+                  <p className="text-dimmed">
+                    No alert rules defined yet. Create one above.
+                  </p>
+                ) : (
+                  <ul className="list-unstyled">
+                    {alerts.map((alert) => {
+                      const hasAccordion =
+                        alert.type === "incoming_tx" ||
+                        alert.type === "outgoing_tx";
+                      const isOpen = !!openAccordions[alert.id];
+                      const edit = getThresholdEdit(alert);
+
+                      return (
+                        <li
+                          key={alert.id}
+                          className={`alerts__rule ${!alert.enabled ? "alerts__rule--disabled" : ""}`}
+                        >
+                          <div className="flex flex--between">
+                            <div>
+                              <div className="text-bold mb-sm">
+                                {formatAlertType(alert.type)}
+                              </div>
+                              {alert.threshold && (
+                                <div className="text-sm text-muted">
+                                  Threshold: {alert.threshold} ETH
+                                </div>
+                              )}
+                              {alert.minimum != null && (
+                                <div className="text-sm text-muted">
+                                  Min: {alert.minimum} ETH
+                                </div>
+                              )}
+                              {alert.maximum != null && (
+                                <div className="text-sm text-muted">
+                                  Max: {alert.maximum} ETH
+                                </div>
+                              )}
+                              <div className="text-xs text-dimmed">
+                                Status:{" "}
+                                {alert.enabled ? "Enabled" : "Disabled"}
+                              </div>
+                            </div>
+                            <div className="flex flex--center gap-sm">
+                              <Button
+                                onClick={() =>
+                                  handleToggleAlert(
+                                    alert.id,
+                                    alert.enabled,
+                                  )
+                                }
+                              >
+                                {alert.enabled ? "Disable" : "Enable"}
+                              </Button>
+                              <Button
+                                onClick={() =>
+                                  handleDeleteAlert(alert.id)
+                                }
+                              >
+                                Delete
+                              </Button>
+                            </div>
+                          </div>
+
+                          {hasAccordion && (
+                            <>
+                              <button
+                                type="button"
+                                className="alerts__accordion-toggle"
+                                onClick={() =>
+                                  toggleAccordion(alert.id)
+                                }
+                              >
+                                <span
+                                  className={`alerts__accordion-chevron ${isOpen ? "alerts__accordion-chevron--open" : ""}`}
+                                >
+                                  &#9654;
+                                </span>
+                                Add optional minimum and maximum
+                                threshold values
+                              </button>
+                              <div
+                                className={`alerts__accordion-panel ${isOpen ? "alerts__accordion-panel--open" : ""}`}
+                              >
+                                <div className="alerts__threshold-inputs">
+                                  <Input
+                                    label="Minimum"
+                                    type="number"
+                                    step="0.000001"
+                                    min="0"
+                                    value={edit.minimum}
+                                    onChange={(v) =>
+                                      setThresholdEdit(
+                                        alert.id,
+                                        "minimum",
+                                        v,
+                                      )
+                                    }
+                                    placeholder="No minimum"
+                                  />
+                                  <Input
+                                    label="Maximum"
+                                    type="number"
+                                    step="0.000001"
+                                    min="0"
+                                    value={edit.maximum}
+                                    onChange={(v) =>
+                                      setThresholdEdit(
+                                        alert.id,
+                                        "maximum",
+                                        v,
+                                      )
+                                    }
+                                    placeholder="No maximum"
+                                  />
+                                </div>
+                                <div className="alerts__threshold-actions">
+                                  <Button
+                                    onClick={() =>
+                                      handleSaveThresholds(alert.id)
+                                    }
+                                    className="btn--sm"
+                                  >
+                                    Save
+                                  </Button>
+                                </div>
+                              </div>
+                            </>
+                          )}
+                        </li>
+                      );
+                    })}
+                  </ul>
+                )}
+              </div>
+            </>
+          )}
+        </div>
+
+        {/* RIGHT COLUMN: Notification Settings */}
+        <div>
+          <h2 className="mt-0">Notification Settings</h2>
+
+          {notificationSuccess && (
+            <div className="alert alert--success">{notificationSuccess}</div>
+          )}
+
+          {notificationError && (
+            <div className="alert alert--error">{notificationError}</div>
+          )}
+
+          {/* Master toggle */}
+          <div className="alerts__toggle-panel">
+            <label className="alerts__toggle-label">
+              <input
+                type="checkbox"
+                checked={notificationEnabled}
+                onChange={(e) =>
+                  setNotificationEnabled(e.target.checked)
+                }
+                className="alerts__toggle-checkbox"
+              />
+              <span className="text-bold">Enable Notifications</span>
+            </label>
+            <div className="alerts__toggle-hint">
+              Master switch for all notification channels
+            </div>
+          </div>
+
+          {/* All channel settings -- hidden when master toggle is off */}
+          {notificationEnabled && (
+            <>
+              {/* Telegram */}
+              <div className={`section${!canTelegram ? " alerts__channel-locked" : ""}`}>
+                <h3 className="mt-0 mb-md">Telegram</h3>
+                {!canTelegram && (
+                  <UpgradeBanner message="Upgrade to Premium to enable Telegram alerts" />
+                )}
+                <Input
+                  label="Bot Token"
+                  value={telegramBotToken}
+                  onChange={setTelegramBotToken}
+                  placeholder="123456789:ABCdefGHIjklMNOpqrSTUvwxYZ"
+                  disabled={!canTelegram}
+                />
+                <Input
+                  label="Chat ID"
+                  value={telegramChatId}
+                  onChange={setTelegramChatId}
+                  placeholder="-1001234567890"
+                  disabled={!canTelegram}
+                />
+                <a
+                  href="https://core.telegram.org/bots#how-do-i-create-a-bot"
+                  target="_blank"
+                  rel="noopener noreferrer"
+                  className="help-link"
+                >
+                  How to create a Telegram bot & get your Chat ID
+                </a>
+              </div>
+
+              {/* Email */}
+              <div className="section">
+                <h3 className="mt-0 mb-md">Email</h3>
+                <Input
+                  label="Email Address"
+                  type="email"
+                  value={email}
+                  onChange={setEmail}
+                  placeholder="you@example.com"
+                />
+                <div className="help-link text-dimmed mb-md">
+                  Alert notifications and digests will be sent to this address
+                </div>
+                <div className="alerts__email-buttons">
+                  <Button
+                    onClick={handleSetupEmail}
+                    disabled={settingUpEmail || !email}
+                    className="btn--sm"
+                  >
+                    {settingUpEmail ? "Setting up..." : "Verify Email"}
+                  </Button>
+                  <Button
+                    onClick={handleSendDigest}
+                    disabled={sendingDigest || !email}
+                    variant="secondary"
+                    className="btn--sm"
+                  >
+                    {sendingDigest ? "Sending..." : "Send Digest Now"}
+                  </Button>
+                </div>
+              </div>
+
+              {/* Discord */}
+              <div className={`section${!canDiscord ? " alerts__channel-locked" : ""}`}>
+                <h3 className="mt-0 mb-md">Discord</h3>
+                {!canDiscord && (
+                  <UpgradeBanner message="Upgrade to Premium to enable Discord alerts" />
+                )}
+                <Input
+                  label="Discord Webhook URL"
+                  value={discordWebhookUrl}
+                  onChange={setDiscordWebhookUrl}
+                  placeholder="https://discord.com/api/webhooks/..."
+                  disabled={!canDiscord}
+                />
+                <a
+                  href="https://support.discord.com/hc/en-us/articles/228383668-Intro-to-Webhooks"
+                  target="_blank"
+                  rel="noopener noreferrer"
+                  className="help-link"
+                >
+                  How to get a Discord webhook URL
+                </a>
+              </div>
+
+              {/* Slack */}
+              <div className={`section${!canSlack ? " alerts__channel-locked" : ""}`}>
+                <h3 className="mt-0 mb-md">Slack</h3>
+                {!canSlack && (
+                  <UpgradeBanner message="Upgrade to Pro to enable Slack alerts" />
+                )}
+                <Input
+                  label="Slack Webhook URL"
+                  value={slackWebhookUrl}
+                  onChange={setSlackWebhookUrl}
+                  placeholder="https://hooks.slack.com/services/..."
+                  disabled={!canSlack}
+                />
+                <a
+                  href="https://api.slack.com/messaging/webhooks"
+                  target="_blank"
+                  rel="noopener noreferrer"
+                  className="help-link"
+                >
+                  How to set up Slack Incoming Webhooks
+                </a>
+              </div>
+
+              {/* Save & Test buttons */}
+              <div className="alerts__save-test">
+                <Button
+                  onClick={handleSaveNotificationConfig}
+                  disabled={notificationLoading}
+                  className="btn--lg"
+                >
+                  {notificationLoading ? "Saving..." : "Save Settings"}
+                </Button>
+                <Button
+                  onClick={handleTestChannels}
+                  disabled={testingChannels}
+                  variant="success"
+                  className="btn--lg"
+                >
+                  {testingChannels ? "Testing..." : "Test All Channels"}
+                </Button>
+              </div>
+            </>
+          )}
+        </div>
+      </div>
+    </div>
+  );
+}
+
+function formatAlertType(type) {
+  const labels = {
+    incoming_tx: "Incoming transaction",
+    outgoing_tx: "Outgoing transaction",
+    large_transfer: "Large transfer",
+    balance_below: "Balance below threshold",
+  };
+  return labels[type] || type;
+}

frontend/src/pages/login/Login.css

@@ -0,0 +1,117 @@
+.login-page {
+  position: relative;
+  width: 100vw;
+  height: 100vh;
+  overflow: hidden;
+  background-color: #000000;
+}
+
+.login-bg-video {
+  position: absolute;
+  top: 50%;
+  left: 50%;
+  min-width: 100%;
+  min-height: 100%;
+  width: auto;
+  height: auto;
+  transform: translate(-50%, -50%);
+  object-fit: cover;
+  z-index: 0;
+  filter: grayscale(85%);
+  -webkit-filter: grayscale(85%);
+  opacity: 0.05;
+}
+
+.login-card {
+  position: relative;
+  z-index: 1;
+  max-width: 400px;
+  margin: 0 auto;
+  padding: 2rem;
+  padding-top: 8rem;
+  border: 1px solid var(--color-border-light);
+  border-radius: var(--radius-xl);
+  background-color: rgba(0, 0, 0, 0.75);
+  top: 20px;
+}
+
+.login-heading {
+  margin-bottom: 2rem;
+  text-align: center;
+  position: relative;
+  top: -20px;
+}
+
+.login-brand {
+  color: var(--color-brand);
+}
+
+.login-button {
+  width: 100%;
+  padding: 0.75rem;
+  font-size: 1.2rem;
+  margin-top: 16px;
+}
+
+.login-footer {
+  margin-top: 1.5rem;
+  text-align: center;
+}
+
+.login-signup-link {
+  color: var(--color-primary);
+  text-decoration: none;
+}
+
+@keyframes fadeIn {
+  from {
+    opacity: 0;
+  }
+
+  to {
+    opacity: 1;
+  }
+}
+
+.login-card-fadein {
+  opacity: 0;
+  animation: fadeIn 2s ease-in-out forwards;
+  animation-delay: 3s;
+}
+
+.login-tagline {
+  position: relative;
+  z-index: 1;
+  max-width: 630px;
+  margin: 5rem auto 0;
+  padding-left: 2rem;
+  font-style: italic;
+  color: #FFFFFF;
+  font-size: 1.5rem;
+  line-height: 1.5;
+  text-align: center;
+}
+
+.login-interactive-fadein {
+  opacity: 0;
+  animation: fadeIn 2s ease-in-out forwards;
+  animation-delay: 6s;
+}
+
+/* ── Login Responsive ────────────────────────────────────── */
+
+@media (max-width: 480px) {
+  .login-card {
+    max-width: 100%;
+    margin: 0 0.75rem;
+    padding: 1.5rem;
+    padding-top: 6rem;
+  }
+
+  .login-tagline {
+    margin-top: 3rem;
+    padding-left: 1rem;
+    padding-right: 1rem;
+    font-size: 1.25rem;
+  }
+}

frontend/src/pages/login/Login.jsx

@@ -1,11 +1,10 @@
 import { useState } from "react";
 import { Link, useNavigate } from "react-router-dom";
-import { useAuth } from "../contexts/AuthContext";
-import Input from "../components/Input";
+import { useAuth } from "../../contexts/AuthContext";
+import Input from "../../components/Input";
 import "./Login.css";
 
 export default function Login() {
-  const [isVisible, setIsVisible] = useState(false);
   const [email, setEmail] = useState("");
   const [password, setPassword] = useState("");
   const [error, setError] = useState("");
@@ -36,12 +35,22 @@ export default function Login() {
 
   return (
     <div className="login-page">
-      <div className="login-card" onMouseEnter={() => setIsVisible(true)}>
+      <video
+        autoPlay
+        loop
+        muted
+        playsInline
+        className="login-bg-video"
+      >
+        <source src="/koin_exp_2.mp4" type="video/mp4" />
+      </video>
+
+      <div className="login-card login-card-fadein">
         <h1 className="login-heading">
           <span className="login-brand">Koin Ping</span> - Login
         </h1>
 
-        <div className={isVisible ? "login-form-visible" : "login-form-hidden"}>
+        <div className="login-interactive-fadein">
           {error && <div className="alert alert--error">{error}</div>}
 
           <form onSubmit={handleSubmit}>
@@ -78,6 +87,11 @@ export default function Login() {
           </div>
         </div>
       </div>
+
+      <p className="login-tagline login-card-fadein">
+        A lightweight, on-chain monitoring system giving users real-time
+        situational awareness over blockchain addresses.
+      </p>
     </div>
   );
 }