tweak

Implement tiers end to end

.gitignore

@@ -22,6 +22,8 @@ node_modules/
 
 # Go build artifacts
 backend/bin/
+backend/api
+backend/poller
 *.exe
 *.exe~
 *.dll

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

@@ -1,20 +1,33 @@
-Start DB:
+Backend startup quickstart:
 
-brew services start postgresql@15
+----------------------------->  BEST
+## 1. brew services start postgresql@15
 
-From the backend directory, you have a few options:
+          OR 
 
-Option 1: Single command (both API + poller)
+      /opt/homebrew/opt/postgresql@15/bin/pg_ctl -D /opt/homebrew/var/postgresql@15 start
-cd /Users/kjannette/workspace/koin_ping_0.2.0/backendmake dev-all
 
-Option 2: Two separate terminals
+## 2.   ALLIN ONE: 
-Terminal 1 (API server):
+        Make dev-all — Runs both the API and poller concurrently.
-cd /Users/kjannette/workspace/koin_ping_0.2.0/backend go run ./cmd/api
+----------------------------->  BEST
-Terminal 2 (Poller):
+
-cd /Users/kjannette/workspace/koin_ping_0.2.0/backend go run ./cmd/poller
+          - 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.
 
-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/cmd/api/main.go

@@ -10,7 +10,6 @@ import (
 	"github.com/joho/godotenv"
 	"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"
@@ -38,10 +37,6 @@ func main() {
 		log.Fatalf("Failed to connect to database: %v", err)
 	}
 
-	if err := firebase.Init(cfg.FirebaseProjectID); err != nil {
-		log.Fatalf("Failed to initialize Firebase: %v", err)
-	}
-
 	defer database.Close()
 
 	userModel := models.NewUserModel(pool)
@@ -55,16 +50,17 @@ func main() {
 		cfg.ResendAPIKey, cfg.EmailFrom, alertEventModel, notifConfigModel,
 	)
 
-	addressHandler := handlers.NewAddressHandler(addressModel)
+	addressHandler := handlers.NewAddressHandler(addressModel, userModel)
-	alertRuleHandler := handlers.NewAlertRuleHandler(alertRuleModel, addressModel)
+	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, cfg)
+	accountHandler := handlers.NewAccountHandler(userModel, addressModel, cfg)
+	authHandler := handlers.NewAuthHandler(userModel, cfg)
 
-	authenticate := middleware.Authenticate(userModel)
+	authenticate := middleware.Authenticate(userModel, cfg.JWTSecret)
 	requireSub := middleware.RequireSubscription(userModel)
 
 	// authAndSub chains authentication + subscription check for protected routes.
@@ -79,9 +75,16 @@ func main() {
 	mux.HandleFunc("GET "+b+"/health", handlers.HealthCheck)
 	mux.HandleFunc("GET "+b+"/status", statusHandler.GetStatus)
 
+	// Auth routes (public — no token required)
+	mux.HandleFunc("POST "+b+"/auth/login", authHandler.Login)
+	mux.HandleFunc("POST "+b+"/auth/register", authHandler.RegisterAfterCheckout)
+
 	// 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)))
@@ -91,6 +94,8 @@ func main() {
 		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",

backend/cmd/poller/main.go

@@ -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,
+		eth, alertRuleModel, alertEventModel, addressModel, userModel, notifConfigModel,
-		cfg.ResendAPIKey, cfg.EmailFrom,
 	)
 	digestSvc := services.NewEmailDigestService(cfg.ResendAPIKey, cfg.EmailFrom, alertEventModel, notifConfigModel)
 

backend/go.mod

@@ -32,6 +32,7 @@ require (
 	github.com/go-logr/logr v1.4.3 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/golang-jwt/jwt/v4 v4.5.2 // indirect
+	github.com/golang-jwt/jwt/v5 v5.3.1 // indirect
 	github.com/golang/protobuf v1.5.4 // indirect
 	github.com/google/s2a-go v0.1.9 // indirect
 	github.com/google/uuid v1.6.0 // indirect
@@ -54,12 +55,12 @@ require (
 	go.opentelemetry.io/otel/sdk v1.39.0 // indirect
 	go.opentelemetry.io/otel/sdk/metric v1.39.0 // indirect
 	go.opentelemetry.io/otel/trace v1.39.0 // indirect
-	golang.org/x/crypto v0.48.0 // indirect
+	golang.org/x/crypto v0.49.0 // indirect
-	golang.org/x/net v0.50.0 // indirect
+	golang.org/x/net v0.51.0 // indirect
 	golang.org/x/oauth2 v0.35.0 // indirect
-	golang.org/x/sync v0.19.0 // indirect
+	golang.org/x/sync v0.20.0 // indirect
-	golang.org/x/sys v0.41.0 // indirect
+	golang.org/x/sys v0.42.0 // indirect
-	golang.org/x/text v0.34.0 // indirect
+	golang.org/x/text v0.35.0 // indirect
 	golang.org/x/time v0.14.0 // indirect
 	google.golang.org/appengine/v2 v2.0.6 // indirect
 	google.golang.org/genproto v0.0.0-20260128011058-8636f8732409 // indirect

backend/go.sum

@@ -61,6 +61,8 @@ github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre
 github.com/golang-jwt/jwt/v4 v4.4.2/go.mod h1:m21LjoU+eqJr34lmDMbreY2eSTRJ1cv77w39/MY0Ch0=
 github.com/golang-jwt/jwt/v4 v4.5.2 h1:YtQM7lnr8iZ+j5q71MGKkNw9Mn7AjHM68uc9g5fXeUI=
 github.com/golang-jwt/jwt/v4 v4.5.2/go.mod h1:m21LjoU+eqJr34lmDMbreY2eSTRJ1cv77w39/MY0Ch0=
+github.com/golang-jwt/jwt/v5 v5.3.1 h1:kYf81DTWFe7t+1VvL7eS+jKFVWaUnK9cB1qbwn63YCY=
+github.com/golang-jwt/jwt/v5 v5.3.1/go.mod h1:fxCRLWMO43lRc8nhHWY6LGqRcf+1gQWArsqaEUEa5bE=
 github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
 github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
 github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
@@ -128,18 +130,24 @@ golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACk
 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/crypto v0.48.0 h1:/VRzVqiRSggnhY7gNRxPauEQ5Drw9haKdM0jqfcCFts=
 golang.org/x/crypto v0.48.0/go.mod h1:r0kV5h3qnFPlQnBSrULhlsRfryS2pmewsg+XfMgkVos=
+golang.org/x/crypto v0.49.0 h1:+Ng2ULVvLHnJ/ZFEq4KdcDd/cfjrrjjNSXNzxg0Y4U4=
+golang.org/x/crypto v0.49.0/go.mod h1:ErX4dUh2UM+CFYiXZRTcMpEcN8b/1gxEuv3nODoYtCA=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
 golang.org/x/net v0.50.0 h1:ucWh9eiCGyDR3vtzso0WMQinm2Dnt8cFMuQa9K33J60=
 golang.org/x/net v0.50.0/go.mod h1:UgoSli3F/pBgdJBHCTc+tp3gmrU4XswgGRgtnwWTfyM=
+golang.org/x/net v0.51.0 h1:94R/GTO7mt3/4wIKpcR5gkGmRLOuE/2hNGeWq/GBIFo=
+golang.org/x/net v0.51.0/go.mod h1:aamm+2QF5ogm02fjy5Bb7CQ0WMt1/WVM7FtyaTLlA9Y=
 golang.org/x/oauth2 v0.35.0 h1:Mv2mzuHuZuY2+bkyWXIHMfhNdJAdwW3FuWeCPYN5GVQ=
 golang.org/x/oauth2 v0.35.0/go.mod h1:lzm5WQJQwKZ3nwavOZ3IS5Aulzxi68dUSgRHujetwEA=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
 golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
+golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
+golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -147,6 +155,8 @@ golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.41.0 h1:Ivj+2Cp/ylzLiEU89QhWblYnOE9zerudt9Ftecq2C6k=
 golang.org/x/sys v0.41.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
+golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
@@ -155,6 +165,8 @@ golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
 golang.org/x/text v0.34.0 h1:oL/Qq0Kdaqxa1KbNeMKwQq0reLCCaFtqu2eNuSeNHbk=
 golang.org/x/text v0.34.0/go.mod h1:homfLqTYRFyVYemLBFl5GgL/DWEiH5wcsQ5gSh1yziA=
+golang.org/x/text v0.35.0 h1:JOVx6vVDFokkpaq1AEptVzLTpDe9KGpj5tR4/X+ybL8=
+golang.org/x/text v0.35.0/go.mod h1:khi/HExzZJ2pGnjenulevKNX1W67CUy0AsXcNubPGCA=
 golang.org/x/time v0.14.0 h1:MRx4UaLrDotUKUdCIqzPC48t1Y9hANFKIRpNx+Te8PI=
 golang.org/x/time v0.14.0/go.mod h1:eL/Oa2bBBK0TkX57Fyni+NgnyQQN4LitPmob2Hjnqw4=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

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/migrations/010_add_password_auth.sql

@@ -0,0 +1,11 @@
+-- Migration 010: Add password-based authentication
+-- Adds password_hash column, makes firebase_uid optional, ensures email uniqueness.
+
+ALTER TABLE users ADD COLUMN IF NOT EXISTS password_hash VARCHAR(255);
+
+ALTER TABLE users ALTER COLUMN firebase_uid DROP NOT NULL;
+
+-- Ensure email is unique so it can serve as the login identifier.
+-- Drop the old index first if it exists, then create a unique one.
+DROP INDEX IF EXISTS idx_users_email_unique;
+CREATE UNIQUE INDEX idx_users_email_unique ON users (email);

backend/infra/schema.sql

@@ -14,6 +14,7 @@ CREATE TABLE users (
   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()

backend/internal/config/config.go

@@ -32,11 +32,13 @@ type Config struct {
 	ResendAPIKey         string
 	EmailFrom            string
 	DigestIntervalHours  int
-	StripeSecretKey      string
+	StripeSecretKey        string
-	StripeWebhookSecret  string
+	StripeWebhookSecret    string
-	StripePriceID        string
+	StripePriceIDPremium   string
-	StripePublishableKey string
+	StripePriceIDPro       string
-	FrontendURL          string
+	StripePublishableKey   string
+	FrontendURL            string
+	JWTSecret              string
 }
 
 // Load reads configuration from environment variables and returns a Config.
@@ -57,11 +59,13 @@ func Load() (*Config, error) {
 		ResendAPIKey:        os.Getenv("RESEND_API_KEY"),
 		EmailFrom:           getEnv("EMAIL_FROM", "Koin Ping <alerts@koinping.com>"),
 		DigestIntervalHours:  getEnvInt("DIGEST_INTERVAL_HOURS", defaultDigestIntervalHours),
-		StripeSecretKey:      os.Getenv("STRIPE_SECRET_KEY"),
+		StripeSecretKey:        os.Getenv("STRIPE_SECRET_KEY"),
-		StripeWebhookSecret:  os.Getenv("STRIPE_WEBHOOK_SECRET"),
+		StripeWebhookSecret:    os.Getenv("STRIPE_WEBHOOK_SECRET"),
-		StripePriceID:        os.Getenv("STRIPE_PRICE_ID"),
+		StripePriceIDPremium:   os.Getenv("STRIPE_PRICE_ID_PREMIUM"),
-		StripePublishableKey: os.Getenv("STRIPE_PUBLISHABLE_KEY"),
+		StripePriceIDPro:       os.Getenv("STRIPE_PRICE_ID_PRO"),
+		StripePublishableKey:   os.Getenv("STRIPE_PUBLISHABLE_KEY"),
 		FrontendURL:          getEnv("FRONTEND_URL", "http://localhost:3000"),
+		JWTSecret:            getEnv("JWT_SECRET", "change-me-in-production"),
 	}
 
 	if cfg.PollIntervalMS < minPollIntervalMS {
@@ -92,6 +96,19 @@ 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

@@ -2,17 +2,78 @@ 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"`
+	ID                    string           `json:"id"`
-	FirebaseUID           string     `json:"-"`
+	FirebaseUID           *string          `json:"-"`
-	Email                 string     `json:"email"`
+	Email                 string           `json:"email"`
-	DisplayName           *string    `json:"display_name"`           //nolint:tagliatelle
+	DisplayName           *string          `json:"display_name"`           //nolint:tagliatelle
-	StripeCustomerID      *string    `json:"-"`
+	PasswordHash          *string          `json:"-"`
-	StripeSubscriptionID  *string    `json:"-"`
+	StripeCustomerID      *string          `json:"-"`
-	SubscriptionStatus    string     `json:"subscription_status"`    //nolint:tagliatelle
+	StripeSubscriptionID  *string          `json:"-"`
-	SubscriptionCreatedAt *time.Time `json:"subscription_created_at,omitempty"` //nolint:tagliatelle
+	SubscriptionStatus    string           `json:"subscription_status"`    //nolint:tagliatelle
-	CreatedAt             time.Time  `json:"created_at"`             //nolint:tagliatelle
+	SubscriptionTier      SubscriptionTier `json:"subscription_tier"`      //nolint:tagliatelle
-	UpdatedAt             time.Time  `json:"updated_at"`             //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 {

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

@@ -6,29 +6,40 @@ import (
 	"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
+	users     *models.UserModel
-	cfg   *config.Config
+	addresses *models.AddressModel
+	cfg       *config.Config
 }
 
-func NewAccountHandler(users *models.UserModel, cfg *config.Config) *AccountHandler {
+func NewAccountHandler(users *models.UserModel, addresses *models.AddressModel, cfg *config.Config) *AccountHandler {
-	return &AccountHandler{users: users, cfg: cfg}
+	return &AccountHandler{users: users, addresses: addresses, cfg: cfg}
 }
 
 type accountResponse struct {
-	UserID             string  `json:"user_id"`
+	UserID             string            `json:"user_id"`
-	Email              string  `json:"email"`
+	Email              string            `json:"email"`
-	UserName           string  `json:"user_name"`
+	UserName           string            `json:"user_name"`
-	SubscriptionStatus string  `json:"subscription_status"`
+	SubscriptionStatus string            `json:"subscription_status"`
-	SubscriptionPlan   string  `json:"subscription_plan"`
+	SubscriptionTier   string            `json:"subscription_tier"`
-	MemberSince        *string `json:"member_since,omitempty"`
+	SubscriptionPlan   string            `json:"subscription_plan"`
-	NextBillingDate    *string `json:"next_billing_date,omitempty"`
+	TierLimits         domain.TierLimits `json:"tier_limits"`
-	CancelAtPeriodEnd  bool    `json:"cancel_at_period_end"`
+	AddressCount       int               `json:"address_count"`
-	PeriodEndDate      *string `json:"period_end_date,omitempty"`
+	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) {
@@ -42,12 +53,26 @@ func (h *AccountHandler) GetAccount(w http.ResponseWriter, r *http.Request) {
 		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,
-		SubscriptionPlan:   "monthly/$1.99",
+		SubscriptionTier:   string(user.SubscriptionTier),
+		SubscriptionPlan:   planLabel,
+		TierLimits:         domain.GetTierLimits(user.SubscriptionTier),
+		AddressCount:       addrCount,
 	}
 
 	if user.SubscriptionCreatedAt != nil {
@@ -55,9 +80,6 @@ func (h *AccountHandler) GetAccount(w http.ResponseWriter, r *http.Request) {
 		resp.MemberSince = &t
 	}
 
-	// MOCKED: NextBillingDate, CancelAtPeriodEnd, PeriodEndDate.
-	// TODO: stripe-go v82 removed Subscription.CurrentPeriodEnd / CancelAtPeriodEnd.
-	// Research SubscriptionItem.CurrentPeriodEnd or use Stripe REST API directly.
 	resp.NextBillingDate = nil
 	resp.CancelAtPeriodEnd = false
 	resp.PeriodEndDate = nil

backend/internal/handlers/address.go

@@ -3,6 +3,7 @@ package handlers
 
 import (
 	"encoding/json"
+	"fmt"
 	"log"
 	"net/http"
 	"regexp"
@@ -17,10 +18,11 @@ 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 {
+func NewAddressHandler(addresses *models.AddressModel, users *models.UserModel) *AddressHandler {
-	return &AddressHandler{addresses: addresses}
+	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_rule.go

@@ -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 {
+func NewAlertRuleHandler(alertRules *models.AlertRuleModel, addresses *models.AddressModel, users *models.UserModel) *AlertRuleHandler {
-	return &AlertRuleHandler{alertRules: alertRules, addresses: addresses}
+	return &AlertRuleHandler{alertRules: alertRules, addresses: addresses, users: users}
 }
 
 func (h *AlertRuleHandler) Create(w http.ResponseWriter, r *http.Request) {
@@ -132,6 +133,28 @@ func (h *AlertRuleHandler) Create(w http.ResponseWriter, r *http.Request) {
 		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.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)

backend/internal/handlers/auth.go

@@ -0,0 +1,230 @@
+package handlers
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+	checkoutsession "github.com/stripe/stripe-go/v82/checkout/session"
+	"golang.org/x/crypto/bcrypt"
+
+	"github.com/kjannette/koin-ping/backend/internal/config"
+	"github.com/kjannette/koin-ping/backend/internal/domain"
+	"github.com/kjannette/koin-ping/backend/internal/models"
+)
+
+const (
+	bcryptCost     = 12
+	jwtTTLHours    = 72
+	minPasswordLen = 6
+)
+
+type AuthHandler struct {
+	users *models.UserModel
+	cfg   *config.Config
+}
+
+func NewAuthHandler(users *models.UserModel, cfg *config.Config) *AuthHandler {
+	return &AuthHandler{users: users, cfg: cfg}
+}
+
+type authResponse struct {
+	Token              string `json:"token"`
+	UserID             string `json:"user_id"`    //nolint:tagliatelle
+	Email              string `json:"email"`
+	SubscriptionStatus string `json:"subscription_status"` //nolint:tagliatelle
+	SubscriptionTier   string `json:"subscription_tier"`   //nolint:tagliatelle
+}
+
+func (h *AuthHandler) issueJWT(userID, email string) (string, error) {
+	claims := jwt.MapClaims{
+		"sub":   userID,
+		"email": email,
+		"iat":   time.Now().Unix(),
+		"exp":   time.Now().Add(jwtTTLHours * time.Hour).Unix(),
+	}
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	return token.SignedString([]byte(h.cfg.JWTSecret))
+}
+
+// Login authenticates an existing user by email + password.
+func (h *AuthHandler) Login(w http.ResponseWriter, r *http.Request) {
+	var body struct {
+		Email    string `json:"email"`
+		Password string `json:"password"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+		writeError(w, http.StatusBadRequest, "BAD_REQUEST", "Invalid request body")
+		return
+	}
+
+	if body.Email == "" || body.Password == "" {
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "Email and password are required")
+		return
+	}
+
+	user, err := h.users.FindByEmail(r.Context(), body.Email)
+	if err != nil {
+		log.Printf("Login: DB error looking up %s: %v", body.Email, err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Login failed")
+		return
+	}
+	if user == nil {
+		writeError(w, http.StatusUnauthorized, "INVALID_CREDENTIALS", "Invalid email or password")
+		return
+	}
+
+	if user.PasswordHash == nil || *user.PasswordHash == "" {
+		writeError(w, http.StatusUnauthorized, "INVALID_CREDENTIALS", "Invalid email or password")
+		return
+	}
+
+	if err := bcrypt.CompareHashAndPassword([]byte(*user.PasswordHash), []byte(body.Password)); err != nil {
+		writeError(w, http.StatusUnauthorized, "INVALID_CREDENTIALS", "Invalid email or password")
+		return
+	}
+
+	token, err := h.issueJWT(user.ID, user.Email)
+	if err != nil {
+		log.Printf("Login: failed to issue JWT for %s: %v", user.ID, err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Login failed")
+		return
+	}
+
+	log.Printf("Login successful for user %s (%s)", user.ID, user.Email)
+	writeJSON(w, http.StatusOK, authResponse{
+		Token:              token,
+		UserID:             user.ID,
+		Email:              user.Email,
+		SubscriptionStatus: user.SubscriptionStatus,
+		SubscriptionTier:   string(user.SubscriptionTier),
+	})
+}
+
+// RegisterAfterCheckout creates a new user account after a successful Stripe
+// checkout. It verifies the Stripe session was paid, hashes the password,
+// inserts the user into Postgres, links the Stripe customer/subscription,
+// and returns a JWT so the frontend is immediately authenticated.
+func (h *AuthHandler) RegisterAfterCheckout(w http.ResponseWriter, r *http.Request) {
+	var body struct {
+		Email     string `json:"email"`
+		Password  string `json:"password"`
+		SessionID string `json:"session_id"` //nolint:tagliatelle
+	}
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+		writeError(w, http.StatusBadRequest, "BAD_REQUEST", "Invalid request body")
+		return
+	}
+
+	if body.Email == "" || body.Password == "" {
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "Email and password are required")
+		return
+	}
+	if len(body.Password) < minPasswordLen {
+		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR", "Password must be at least 6 characters")
+		return
+	}
+
+	existing, err := h.users.FindByEmail(r.Context(), body.Email)
+	if err != nil {
+		log.Printf("Register: DB error looking up %s: %v", body.Email, err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Registration failed")
+		return
+	}
+	if existing != nil {
+		writeError(w, http.StatusConflict, "EMAIL_IN_USE", "An account with this email already exists")
+		return
+	}
+
+	hash, err := bcrypt.GenerateFromPassword([]byte(body.Password), bcryptCost)
+	if err != nil {
+		log.Printf("Register: bcrypt error: %v", err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Registration failed")
+		return
+	}
+
+	user, err := h.users.CreateWithPassword(r.Context(), body.Email, string(hash))
+	if err != nil {
+		log.Printf("Register: failed to create user %s: %v", body.Email, err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Registration failed")
+		return
+	}
+
+	// If a Stripe session_id was provided (paid tier checkout), link the
+	// Stripe customer and activate the subscription immediately.
+	if body.SessionID != "" {
+		h.linkStripeSession(r, user.ID, body.SessionID)
+	}
+
+	// Re-fetch to pick up updated subscription fields after Stripe link.
+	user, err = h.users.GetByID(r.Context(), user.ID)
+	if err != nil || user == nil {
+		log.Printf("Register: failed to re-fetch user %s: %v", body.Email, err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Registration failed")
+		return
+	}
+
+	token, err := h.issueJWT(user.ID, user.Email)
+	if err != nil {
+		log.Printf("Register: failed to issue JWT for %s: %v", user.ID, err)
+		writeError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "Registration failed")
+		return
+	}
+
+	log.Printf("Registration successful for user %s (%s)", user.ID, user.Email)
+	writeJSON(w, http.StatusOK, authResponse{
+		Token:              token,
+		UserID:             user.ID,
+		Email:              user.Email,
+		SubscriptionStatus: user.SubscriptionStatus,
+		SubscriptionTier:   string(user.SubscriptionTier),
+	})
+}
+
+// linkStripeSession retrieves the Stripe checkout session by ID, verifies
+// payment, and writes the Stripe customer + subscription to the user record.
+func (h *AuthHandler) linkStripeSession(r *http.Request, userID, sessionID string) {
+	s, err := checkoutsession.Get(sessionID, nil)
+	if err != nil {
+		log.Printf("linkStripeSession: failed to retrieve session %s: %v", sessionID, err)
+		return
+	}
+
+	fullJSON, _ := json.MarshalIndent(s, "", "  ")
+	log.Printf("STRIPE REGISTER LINK — FULL SESSION:\n%s", string(fullJSON))
+
+	if s.PaymentStatus != "paid" {
+		log.Printf("linkStripeSession: session %s not paid (status=%s)", sessionID, s.PaymentStatus)
+		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("linkStripeSession: 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("linkStripeSession: failed to activate subscription: %v", err)
+		}
+	}
+
+	log.Printf("linkStripeSession: linked user %s → customer %s, subscription %s, tier %s",
+		userID, customerID, subscriptionID, tier)
+}

backend/internal/handlers/notification_config.go

@@ -18,11 +18,12 @@ 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 {
+func NewNotificationConfigHandler(configs *models.NotificationConfigModel, users *models.UserModel, cfg *config.Config) *NotificationConfigHandler {
-	return &NotificationConfigHandler{configs: configs, cfg: cfg}
+	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/stripe.go

@@ -2,6 +2,7 @@ package handlers
 
 import (
 	"encoding/json"
+	"fmt"
 	"io"
 	"log"
 	"net/http"
@@ -12,6 +13,7 @@ import (
 	"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"
 )
@@ -28,10 +30,45 @@ func NewStripeHandler(users *models.UserModel, cfg *config.Config) *StripeHandle
 	return &StripeHandler{users: users, cfg: cfg}
 }
 
-// CreateCheckoutSession creates a Stripe Checkout session for the monthly subscription.
+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)
@@ -43,7 +80,7 @@ func (h *StripeHandler) CreateCheckoutSession(w http.ResponseWriter, r *http.Req
 		Mode: stripe.String(string(stripe.CheckoutSessionModeSubscription)),
 		LineItems: []*stripe.CheckoutSessionLineItemParams{
 			{
-				Price:    stripe.String(h.cfg.StripePriceID),
+				Price:    stripe.String(priceID),
 				Quantity: stripe.Int64(1),
 			},
 		},
@@ -53,6 +90,8 @@ func (h *StripeHandler) CreateCheckoutSession(w http.ResponseWriter, r *http.Req
 		CustomerEmail:     stripe.String(user.Email),
 	}
 
+	params.AddMetadata("tier", string(tier))
+
 	if user.StripeCustomerID != nil && *user.StripeCustomerID != "" {
 		params.Customer = user.StripeCustomerID
 		params.CustomerEmail = nil
@@ -80,14 +119,14 @@ func (h *StripeHandler) GetSubscriptionStatus(w http.ResponseWriter, r *http.Req
 	}
 
 	writeJSON(w, http.StatusOK, map[string]any{
-		"subscription_status":     user.SubscriptionStatus,
+		"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.
-// This is the primary activation path; webhooks serve as a backup.
 func (h *StripeHandler) VerifyCheckoutSession(w http.ResponseWriter, r *http.Request) {
 	userID := middleware.GetUserID(r.Context())
 
@@ -106,7 +145,11 @@ func (h *StripeHandler) VerifyCheckoutSession(w http.ResponseWriter, r *http.Req
 		return
 	}
 
-	if s.ClientReferenceID != userID {
+	if fullJSON, marshalErr := json.MarshalIndent(s, "", "  "); marshalErr == nil {
+		log.Printf("STRIPE VERIFY CHECKOUT — FULL SESSION:\n%s", string(fullJSON))
+	}
+
+	if s.ClientReferenceID != "" && s.ClientReferenceID != userID {
 		writeError(w, http.StatusForbidden, "FORBIDDEN", "Session does not belong to this user")
 		return
 	}
@@ -116,6 +159,11 @@ func (h *StripeHandler) VerifyCheckoutSession(w http.ResponseWriter, r *http.Req
 		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
@@ -131,13 +179,96 @@ func (h *StripeHandler) VerifyCheckoutSession(w http.ResponseWriter, r *http.Req
 		}
 	}
 	if subscriptionID != "" && customerID != "" {
-		if err := h.users.ActivateSubscription(r.Context(), customerID, subscriptionID, "active"); err != nil {
+		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", userID, customerID, subscriptionID)
+	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"})
+	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
+	}
+
+	if fullJSON, marshalErr := json.MarshalIndent(s, "", "  "); marshalErr == nil {
+		log.Printf("STRIPE ONBOARDING CHECKOUT CREATED — FULL SESSION:\n%s", string(fullJSON))
+	}
+
+	writeJSON(w, http.StatusOK, map[string]string{"url": s.URL})
 }
 
 // CreatePortalSession creates a Stripe Billing Portal session so the user can
@@ -173,7 +304,6 @@ func (h *StripeHandler) CreatePortalSession(w http.ResponseWriter, r *http.Reque
 }
 
 // HandleWebhook processes incoming Stripe webhook events.
-// This endpoint must NOT require authentication (Stripe calls it directly).
 func (h *StripeHandler) HandleWebhook(w http.ResponseWriter, r *http.Request) {
 	payload, err := io.ReadAll(io.LimitReader(r.Body, webhookMaxBodyBytes))
 	if err != nil {
@@ -205,6 +335,8 @@ func (h *StripeHandler) HandleWebhook(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *StripeHandler) handleCheckoutCompleted(r *http.Request, event stripe.Event) {
+	log.Printf("STRIPE CHECKOUT COMPLETED — FULL RAW PAYLOAD:\n%s", string(event.Data.Raw))
+
 	var session stripe.CheckoutSession
 	if err := json.Unmarshal(event.Data.Raw, &session); err != nil {
 		log.Printf("Error parsing checkout session: %v", err)
@@ -217,6 +349,11 @@ func (h *StripeHandler) handleCheckoutCompleted(r *http.Request, event stripe.Ev
 		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
@@ -233,12 +370,12 @@ func (h *StripeHandler) handleCheckoutCompleted(r *http.Request, event stripe.Ev
 	}
 
 	if subscriptionID != "" && customerID != "" {
-		if err := h.users.ActivateSubscription(r.Context(), customerID, subscriptionID, "active"); err != nil {
+		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", userID, customerID, subscriptionID)
+	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) {
@@ -257,11 +394,26 @@ func (h *StripeHandler) handleSubscriptionUpdated(r *http.Request, event stripe.
 	}
 
 	status := string(sub.Status)
-	if err := h.users.ActivateSubscription(r.Context(), customerID, sub.ID, status); err != nil {
+
-		log.Printf("Failed to update subscription status: %v", err)
+	// 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
+				}
+			}
+		}
 	}
 
-	log.Printf("Subscription %s updated to %s for customer %s", sub.ID, status, customerID)
+	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) {

backend/internal/middleware/auth.go

@@ -8,7 +8,8 @@ import (
 	"net/http"
 	"strings"
 
-	fbauth "github.com/kjannette/koin-ping/backend/internal/firebase"
+	"github.com/golang-jwt/jwt/v5"
+
 	"github.com/kjannette/koin-ping/backend/internal/models"
 )
 
@@ -17,6 +18,7 @@ type contextKey string
 const (
 	UserIDKey    contextKey = "user_id"
 	UserEmailKey contextKey = "user_email"
+	UserTierKey  contextKey = "user_tier"
 )
 
 type errorResponse struct {
@@ -30,10 +32,9 @@ func writeJSON(w http.ResponseWriter, status int, v interface{}) {
 	json.NewEncoder(w).Encode(v) //nolint:errcheck
 }
 
-// Authenticate verifies the Firebase ID token and auto-provisions a local user
+// Authenticate verifies the JWT from the Authorization header, loads the local
-// record. The local user UUID (not the Firebase UID) is placed into context so
+// user from Postgres, and injects the user UUID + email + tier into context.
-// all downstream handlers use it as the canonical user identifier.
+func Authenticate(userModel *models.UserModel, jwtSecret string) func(http.Handler) http.Handler {
-func Authenticate(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) {
 			authHeader := r.Header.Get("Authorization")
@@ -46,9 +47,8 @@ func Authenticate(userModel *models.UserModel) func(http.Handler) http.Handler {
 				return
 			}
 
-			token := strings.TrimPrefix(authHeader, "Bearer ")
+			rawToken := strings.TrimPrefix(authHeader, "Bearer ")
-			if token == "" {
+			if rawToken == "" {
-				log.Println("Empty token")
 				writeJSON(w, http.StatusUnauthorized, errorResponse{
 					Error:   "UNAUTHORIZED",
 					Message: "Invalid token format",
@@ -56,12 +56,19 @@ func Authenticate(userModel *models.UserModel) func(http.Handler) http.Handler {
 				return
 			}
 
-			log.Println("Verifying Firebase token...")
+			parsed, err := jwt.Parse(rawToken, func(t *jwt.Token) (interface{}, error) {
-			decoded, err := fbauth.Auth().VerifyIDToken(r.Context(), token)
+				if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
-			if err != nil {
+					return nil, jwt.ErrSignatureInvalid
-				log.Printf("Token verification failed: %v", err)
+				}
+				return []byte(jwtSecret), nil
+			})
+			if err != nil || !parsed.Valid {
+				log.Printf("JWT verification failed: %v", err)
 
-				errMsg := err.Error()
+				errMsg := ""
+				if err != nil {
+					errMsg = err.Error()
+				}
 				if strings.Contains(errMsg, "expired") {
 					writeJSON(w, http.StatusUnauthorized, errorResponse{
 						Error:   "TOKEN_EXPIRED",
@@ -77,23 +84,41 @@ func Authenticate(userModel *models.UserModel) func(http.Handler) http.Handler {
 				return
 			}
 
-			firebaseUID := decoded.UID
+			claims, ok := parsed.Claims.(jwt.MapClaims)
-			email, _ := decoded.Claims["email"].(string)
+			if !ok {
-
+				writeJSON(w, http.StatusUnauthorized, errorResponse{
-			user, err := userModel.FindOrCreateByFirebaseUID(r.Context(), firebaseUID, email)
+					Error:   "UNAUTHORIZED",
-			if err != nil {
+					Message: "Invalid token claims",
-				log.Printf("Failed to provision local user for Firebase UID %s: %v", firebaseUID, err)
-				writeJSON(w, http.StatusInternalServerError, errorResponse{
-					Error:   "INTERNAL_ERROR",
-					Message: "Failed to initialize user account",
 				})
 				return
 			}
 
-			log.Printf("Token verified! User UUID: %s, Email: %s", user.ID, email)
+			userID, _ := claims["sub"].(string)
+			email, _ := claims["email"].(string)
+
+			if userID == "" {
+				writeJSON(w, http.StatusUnauthorized, errorResponse{
+					Error:   "UNAUTHORIZED",
+					Message: "Invalid token: missing user ID",
+				})
+				return
+			}
+
+			user, err := userModel.GetByID(r.Context(), userID)
+			if err != nil || user == nil {
+				log.Printf("JWT auth: user %s not found in DB: %v", userID, err)
+				writeJSON(w, http.StatusUnauthorized, errorResponse{
+					Error:   "UNAUTHORIZED",
+					Message: "User account not found",
+				})
+				return
+			}
+
+			log.Printf("JWT verified — User UUID: %s, Email: %s", user.ID, email)
 
 			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))
 		})
@@ -150,3 +175,10 @@ 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

@@ -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
+		`SELECT a.id, a.user_id, a.address, a.label, a.created_at
-		 FROM addresses
+		 FROM addresses a
-		 ORDER BY created_at DESC`,
+		 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_rule.go

@@ -121,6 +121,15 @@ func (m *AlertRuleModel) UpdateThresholds(ctx context.Context, id int, minimum,
 	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`,

backend/internal/models/notification_config.go

@@ -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,
+		`SELECT nc.user_id, nc.discord_webhook_url, nc.telegram_chat_id, nc.telegram_bot_token,
-		        email, slack_webhook_url
+		        nc.email, nc.slack_webhook_url
-		 FROM user_notification_configs
+		 FROM user_notification_configs nc
-		 WHERE notification_enabled = TRUE`,
+		 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

@@ -17,16 +17,16 @@ func NewUserModel(pool *pgxpool.Pool) *UserModel {
 	return &UserModel{pool: pool}
 }
 
-const userColumns = `id, firebase_uid, email, display_name,
+const userColumns = `id, firebase_uid, email, display_name, password_hash,
 	stripe_customer_id, stripe_subscription_id, subscription_status,
-	subscription_created_at, created_at, updated_at`
+	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.ID, &u.FirebaseUID, &u.Email, &u.DisplayName, &u.PasswordHash,
 		&u.StripeCustomerID, &u.StripeSubscriptionID, &u.SubscriptionStatus,
-		&u.SubscriptionCreatedAt, &u.CreatedAt, &u.UpdatedAt,
+		&u.SubscriptionTier, &u.SubscriptionCreatedAt, &u.CreatedAt, &u.UpdatedAt,
 	)
 	if err != nil {
 		if errors.Is(err, pgx.ErrNoRows) {
@@ -51,6 +51,23 @@ func (m *UserModel) FindOrCreateByFirebaseUID(ctx context.Context, firebaseUID,
 	return scanUser(row)
 }
 
+func (m *UserModel) FindByEmail(ctx context.Context, email string) (*domain.User, error) {
+	row := m.pool.QueryRow(ctx,
+		`SELECT `+userColumns+` FROM users WHERE email = $1`, email,
+	)
+	return scanUser(row)
+}
+
+func (m *UserModel) CreateWithPassword(ctx context.Context, email, passwordHash string) (*domain.User, error) {
+	row := m.pool.QueryRow(ctx,
+		`INSERT INTO users (email, password_hash)
+		 VALUES ($1, $2)
+		 RETURNING `+userColumns,
+		email, passwordHash,
+	)
+	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,
@@ -66,15 +83,37 @@ func (m *UserModel) UpdateStripeCustomer(ctx context.Context, userID, stripeCust
 	return err
 }
 
-func (m *UserModel) ActivateSubscription(ctx context.Context, stripeCustomerID, subscriptionID, status string) error {
+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,
+		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
 }

backend/internal/services/evaluator.go

@@ -28,9 +28,8 @@ 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
 }
@@ -40,18 +39,16 @@ 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),
 	}
 }
@@ -254,14 +251,16 @@ func (s *EvaluatorService) WaitForNotifications() {
 	s.notifWg.Wait()
 }
 
-func (s *EvaluatorService) buildNotifiers(cfg *domain.NotificationConfig) []notifications.Notifier {
+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,
@@ -269,17 +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 != "" {
+	// Email is delivered exclusively via the daily digest service, never real-time.
-		notifiers = append(notifiers, &notifications.EmailNotifier{
-			APIKey: s.resendAPIKey,
-			From:   s.emailFrom,
-			To:     *cfg.Email,
-		})
-	}
 
 	return notifiers
 }
@@ -325,6 +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,
@@ -332,7 +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 {

frontend/src/App.jsx

@@ -2,7 +2,6 @@ import { Routes, Route, Navigate } from "react-router-dom";
 import { useAuth } from "./contexts/AuthContext";
 import Navbar from "./components/Navbar";
 import Login from "./pages/login/Login";
-import Signup from "./pages/Signup";
 import Subscribe from "./pages/subscribe/Subscribe";
 import Addresses from "./pages/addresses/Addresses";
 import Alerts from "./pages/alerts/Alerts";
@@ -10,19 +9,31 @@ import AlertHistory from "./pages/alertHistory/AlertHistory";
 import Account from "./pages/user_account/Account";
 
 export default function App() {
-  const { currentUser } = useAuth();
+  const { isAuthenticated, isSubscribed, user } = useAuth();
 
-  if (!currentUser) {
+  // Unauthenticated: show login + onboarding routes only
+  if (!isAuthenticated) {
     return (
       <Routes>
         <Route path="/login" element={<Login />} />
-        <Route path="/signup" element={<Signup />} />
         <Route path="/subscribe" element={<Subscribe />} />
         <Route path="*" element={<Navigate to="/login" />} />
       </Routes>
     );
   }
 
+  // Authenticated but no active subscription: force through subscribe flow
+  if (!isSubscribed) {
+    return (
+      <Routes>
+        <Route path="/subscribe" element={<Subscribe />} />
+        <Route path="/account" element={<><Navbar /><Account /></>} />
+        <Route path="*" element={<Navigate to="/subscribe" />} />
+      </Routes>
+    );
+  }
+
+  // Fully authenticated + subscribed: main app
   return (
     <div>
       <Navbar />

frontend/src/api/auth.js

@@ -0,0 +1,27 @@
+import { API_BASE } from "./config";
+
+export async function loginUser(email, password) {
+  const res = await fetch(`${API_BASE}/auth/login`, {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify({ email, password }),
+  });
+  const data = await res.json();
+  if (!res.ok) {
+    throw new Error(data.message || "Login failed");
+  }
+  return data;
+}
+
+export async function registerAfterCheckout(email, password, sessionId) {
+  const res = await fetch(`${API_BASE}/auth/register`, {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify({ email, password, session_id: sessionId || "" }),
+  });
+  const data = await res.json();
+  if (!res.ok) {
+    throw new Error(data.message || "Registration failed");
+  }
+  return data;
+}

frontend/src/api/authHeaders.js

@@ -1,46 +1,31 @@
 /**
  * Auth Headers Helper
  *
- * Provides authentication headers for API calls
+ * Provides authentication headers for API calls.
- * Includes Firebase ID token in Authorization header
+ * Reads the JWT from localStorage (set by AuthContext on login).
  */
 
-import { auth } from "../firebase/config";
+export function getAuthHeaders() {
+  const token = localStorage.getItem("kp_token");
 
-/**
+  if (!token) {
- * Get headers with authentication token
+    throw new Error("No authenticated user");
- * @returns {Promise<Object>} Headers object with Authorization
+  }
- */
-export async function getAuthHeaders() {
-    const currentUser = auth.currentUser;
 
-    if (!currentUser) {
+  return {
-        throw new Error("No authenticated user");
+    "Content-Type": "application/json",
-    }
+    Authorization: `Bearer ${token}`,
-
+  };
-    // Get Firebase ID token
-    const token = await currentUser.getIdToken();
-
-    return {
-        "Content-Type": "application/json",
-        Authorization: `Bearer ${token}`,
-    };
 }
 
-/**
+export function getAuthHeadersSimple() {
- * Get headers for non-JSON requests (e.g., DELETE with no body)
+  const token = localStorage.getItem("kp_token");
- * @returns {Promise<Object>} Headers object with Authorization
- */
-export async function getAuthHeadersSimple() {
-    const currentUser = auth.currentUser;
 
-    if (!currentUser) {
+  if (!token) {
-        throw new Error("No authenticated user");
+    throw new Error("No authenticated user");
-    }
+  }
 
-    const token = await currentUser.getIdToken();
+  return {
-
+    Authorization: `Bearer ${token}`,
-    return {
+  };
-        Authorization: `Bearer ${token}`,
-    };
 }

frontend/src/api/stripe.jsx

@@ -1,15 +1,42 @@
 import { getAuthHeaders } from "./authHeaders";
 import { API_BASE } from "./config";
 
-export async function createCheckoutSession() {
+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 create checkout session");
+        throw new Error(data.message || "Failed to activate free tier");
     }
     return res.json();
 }

frontend/src/components/Navbar.jsx

@@ -11,11 +11,11 @@ const navLinks = [
 ];
 
 export default function Navbar() {
-  const { currentUser, logout } = useAuth();
+  const { user, logout } = useAuth();
   const location = useLocation();
   const [isNavPanelOpen, setIsNavPanelOpen] = useState(false);
 
-  if (!currentUser) return null;
+  if (!user) return null;
 
   return (
     <>
@@ -24,7 +24,7 @@ export default function Navbar() {
           <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}
+              {user.email}
             </Link>
           </div>
           <div className="navbar__links">
@@ -45,7 +45,7 @@ export default function Navbar() {
 
         <div className="navbar__right">
           <Link to="/account" className="navbar__user navbar__user-link navbar__user-link--desktop">
-            {currentUser.email}
+            {user.email}
           </Link>
           <button onClick={logout} className="navbar__logout">
             Logout

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/contexts/AuthContext.jsx

@@ -1,114 +1,98 @@
-/**
+import { createContext, useReducer, useContext, useEffect, useCallback, useRef } from "react";
- * AuthContext - Firebase Authentication State Management
+import authReducer, { initialState, ACTION_TYPES } from "../reducers/authReducer";
- *
+import { loginUser, registerAfterCheckout } from "../api/auth";
- * Provides authentication state and methods throughout the app
+import { getAccount } from "../api/account";
- */
 
-import { createContext, useContext, useEffect, useState } from "react";
+const AuthContext = createContext(null);
-import {
-    createUserWithEmailAndPassword,
-    signInWithEmailAndPassword,
-    signOut,
-    onAuthStateChanged,
-} from "firebase/auth";
-import { auth } from "../firebase/config";
 
-const AuthContext = createContext();
-
-/**
- * Hook to access auth context
- * @returns {Object} Auth context value
- */
-export function useAuth() {
-    const context = useContext(AuthContext);
-    if (!context) {
-        throw new Error("useAuth must be used within AuthProvider");
-    }
-    return context;
-}
-
-/**
- * AuthProvider - Wraps app and provides auth state
- */
 export function AuthProvider({ children }) {
-    const [currentUser, setCurrentUser] = useState(null);
+  const [state, dispatch] = useReducer(authReducer, initialState);
-    const [loading, setLoading] = useState(true);
+  const fetchedRef = useRef(false);
-    const [error, setError] = useState(null);
 
-    /**
+  const fetchAccount = useCallback(async () => {
-     * Sign up with email and password
+    try {
-     */
+      const account = await getAccount();
-    async function signup(email, password) {
+      dispatch({
-        try {
+        type: ACTION_TYPES.SET_USER,
-            setError(null);
+        payload: {
-            const result = await createUserWithEmailAndPassword(
+          id: account.user_id,
-                auth,
+          email: account.email,
-                email,
+          subscriptionStatus: account.subscription_status,
-                password,
+          subscriptionTier: account.subscription_tier,
-            );
+          tierLimits: account.tier_limits,
-            return result.user;
+          addressCount: account.address_count,
-        } catch (err) {
+        },
-            setError(err.message);
+      });
-            throw err;
+    } catch {
-        }
+      dispatch({ type: ACTION_TYPES.LOGOUT });
     }
+  }, []);
 
-    /**
+  // On mount, if we have a token in localStorage, hydrate user from backend.
-     * Log in with email and password
+  useEffect(() => {
-     */
+    if (!state.token || fetchedRef.current) return;
-    async function login(email, password) {
+    fetchedRef.current = true;
-        try {
+    fetchAccount();
-            setError(null);
+  }, [state.token, fetchAccount]);
-            const result = await signInWithEmailAndPassword(
-                auth,
-                email,
-                password,
-            );
-            return result.user;
-        } catch (err) {
-            setError(err.message);
-            throw err;
-        }
-    }
 
-    /**
+  async function login(email, password) {
-     * Log out current user
+    const data = await loginUser(email, password);
-     */
+    dispatch({ type: ACTION_TYPES.LOGIN_SUCCESS, payload: data });
-    async function logout() {
+    fetchedRef.current = false;
-        try {
+    return data;
-            setError(null);
+  }
-            await signOut(auth);
-        } catch (err) {
-            setError(err.message);
-            throw err;
-        }
-    }
 
-    /**
+  async function register(email, password, sessionId) {
-     * Listen for auth state changes
+    const data = await registerAfterCheckout(email, password, sessionId);
-     */
+    dispatch({ type: ACTION_TYPES.LOGIN_SUCCESS, payload: data });
-    useEffect(() => {
+    fetchedRef.current = false;
-        const unsubscribe = onAuthStateChanged(auth, (user) => {
+    return data;
-            setCurrentUser(user);
+  }
-            setLoading(false);
-        });
 
-        // Cleanup subscription
+  function logout() {
-        return unsubscribe;
+    fetchedRef.current = false;
-    }, []);
+    dispatch({ type: ACTION_TYPES.LOGOUT });
+  }
 
-    const value = {
+  function refreshAccount() {
-        currentUser,
+    fetchAccount();
-        signup,
+  }
-        login,
-        logout,
-        error,
-        loading,
-    };
 
-    return (
+  const isAuthenticated = state.isAuthenticated && !!state.token;
-        <AuthContext.Provider value={value}>
+  const isSubscribed =
-            {!loading && children}
+    state.user?.subscriptionStatus === "active" ||
-        </AuthContext.Provider>
+    state.user?.subscriptionStatus === "trialing";
-    );
+
+  const tierLimits = state.user?.tierLimits || {
+    max_addresses: 1,
+    max_alert_types: 1,
+    allowed_channels: ["email"],
+  };
+
+  const value = {
+    user: state.user,
+    token: state.token,
+    isAuthenticated,
+    isSubscribed,
+    tierLimits,
+    userTier: state.user?.subscriptionTier || "free",
+    login,
+    register,
+    logout,
+    refreshAccount,
+    dispatch,
+    ACTION_TYPES,
+  };
+
+  return <AuthContext.Provider value={value}>{children}</AuthContext.Provider>;
 }
+
+export function useAuth() {
+  const context = useContext(AuthContext);
+  if (!context) {
+    throw new Error("useAuth must be used within an AuthProvider");
+  }
+  return context;
+}
+
+export default useAuth;

frontend/src/index.css

@@ -397,6 +397,14 @@ button {
   }
 }
 
+/* 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 {

frontend/src/pages/addresses/Addresses.jsx

@@ -1,15 +1,22 @@
 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 {
@@ -32,6 +39,7 @@ export default function Addresses() {
       const newAddress = await createAddress(data);
       setAddresses((prev) => [...prev, newAddress]);
       setError(null);
+      refreshAccount();
     } catch (err) {
       setError(err.message);
       console.error("Failed to create address:", err);
@@ -47,6 +55,7 @@ export default function Addresses() {
       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);
@@ -80,7 +89,13 @@ export default function Addresses() {
     <div className="page">
       <h1>Add Addresses to Track</h1>
 
-      <div className="mb-xl">
+      {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>
 

frontend/src/pages/alerts/Alerts.css

@@ -125,6 +125,20 @@
   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 */

frontend/src/pages/alerts/Alerts.jsx

@@ -1,7 +1,9 @@
 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,
@@ -20,6 +22,8 @@ import {
 import "./Alerts.css";
 
 export default function Alerts() {
+  const { tierLimits, userTier } = useAuth();
+
   const [addresses, setAddresses] = useState([]);
   const [selectedAddressId, setSelectedAddressId] = useState(null);
   const [alerts, setAlerts] = useState([]);
@@ -43,6 +47,21 @@ export default function Alerts() {
   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] }));
   }
@@ -209,11 +228,11 @@ export default function Alerts() {
 
       const config = {
         notification_enabled: notificationEnabled,
-        discord_webhook_url: discordWebhookUrl || null,
+        discord_webhook_url: canDiscord ? (discordWebhookUrl || null) : null,
-        telegram_bot_token: telegramBotToken || null,
+        telegram_bot_token: canTelegram ? (telegramBotToken || null) : null,
-        telegram_chat_id: telegramChatId || null,
+        telegram_chat_id: canTelegram ? (telegramChatId || null) : null,
         email: email || null,
-        slack_webhook_url: slackWebhookUrl || null,
+        slack_webhook_url: canSlack ? (slackWebhookUrl || null) : null,
       };
 
       await updateNotificationConfig(config);
@@ -357,7 +376,13 @@ export default function Alerts() {
                 </div>
               </div>
 
-              <div className="mb-xl">
+              {atAlertLimit && userTier !== "pro" && (
+                <UpgradeBanner
+                  message={`Your ${userTier} plan allows ${maxAlertTypes} alert type${maxAlertTypes !== 1 ? "s" : ""} per address. Upgrade for more.`}
+                />
+              )}
+
+              <div className={`mb-xl${atAlertLimit ? " tier-locked" : ""}`}>
                 <h3>Create New Alert</h3>
                 <AlertForm onSubmit={handleAlertSubmit} />
               </div>
@@ -540,19 +565,24 @@ export default function Alerts() {
           {notificationEnabled && (
             <>
               {/* Telegram */}
-              <div className="section">
+              <div className={`section${!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"
@@ -597,13 +627,17 @@ export default function Alerts() {
               </div>
 
               {/* Discord */}
-              <div className="section">
+              <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"
@@ -616,13 +650,17 @@ export default function Alerts() {
               </div>
 
               {/* Slack */}
-              <div className="section">
+              <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"

frontend/src/pages/login/Login.jsx

@@ -27,7 +27,11 @@ export default function Login() {
       await login(email, password);
       navigate("/addresses");
     } catch (err) {
-      setError("Failed to log in: " + err.message);
+      if (err.message.includes("Invalid email or password")) {
+        setError("Invalid email or password. Check your credentials or create a new account.");
+      } else {
+        setError("Failed to log in: " + err.message);
+      }
     } finally {
       setLoading(false);
     }
@@ -80,7 +84,7 @@ export default function Login() {
           <div className="login-footer">
             <p className="text-muted">
               Don't have an account?{" "}
-              <Link to="/signup" className="login-signup-link">
+              <Link to="/subscribe" className="login-signup-link">
                 Sign up here
               </Link>
             </p>

frontend/src/pages/subscribe/Subscribe.css

@@ -15,6 +15,10 @@
   padding: 0 1rem;
 }
 
+.subscribe__container--wide {
+  max-width: 920px;
+}
+
 .subscribe__title {
   text-align: center;
   margin-bottom: 2rem;
@@ -107,52 +111,6 @@
   color: #888;
 }
 
-/* Step 5 summary */
-.subscribe__summary {
-  background-color: #1e2e1e;
-  border: 1px solid #2d5a2d;
-  border-radius: var(--radius-lg);
-  padding: 1rem 1.25rem;
-  margin-bottom: 1.5rem;
-}
-
-.subscribe__summary-title {
-  margin: 0 0 0.5rem;
-  color: #90ee90;
-  font-weight: bold;
-}
-
-.subscribe__summary-list {
-  margin: 0;
-  padding-left: 1.25rem;
-  color: var(--color-text-label);
-  line-height: 1.8;
-}
-
-/* Checkbox rows */
-.checkbox-row {
-  margin-bottom: 1rem;
-}
-
-.checkbox-row__label {
-  display: flex;
-  align-items: center;
-  gap: 0.6rem;
-  cursor: pointer;
-  color: #ddd;
-}
-
-.checkbox-row__input {
-  width: 16px;
-  height: 16px;
-  accent-color: var(--color-primary);
-}
-
-.checkbox-row__nested {
-  margin-top: 0.5rem;
-  margin-left: 1.75rem;
-}
-
 /* Footer navigation */
 .subscribe__footer {
   display: flex;
@@ -163,20 +121,6 @@
   border-top: 1px solid var(--color-border-light);
 }
 
-/* Test results */
-.test-result {
-  font-size: 0.9rem;
-  margin-bottom: 0.25rem;
-}
-
-.test-result--success {
-  color: #90ee90;
-}
-
-.test-result--failure {
-  color: var(--color-error);
-}
-
 /* Step subtitle */
 .subscribe__subtitle {
   color: #aaa;
@@ -184,7 +128,7 @@
   font-size: 0.9rem;
 }
 
-/* Subscribe card (Step 2) */
+/* Subscribe card (Step 2 tier cards) */
 .subscribe-card {
   background-color: var(--color-bg-card, #1a1a2e);
   border: 1px solid var(--color-border-light);

frontend/src/pages/subscribe/Subscribe.jsx

@@ -1,99 +1,86 @@
-import { useState, useEffect } from "react";
+import { useState, useEffect, useRef } from "react";
 import { useNavigate, useSearchParams } from "react-router-dom";
 import { useAuth } from "../../contexts/AuthContext";
-import { createAddress, getAddresses } from "../../api/addresses";
+import { createOnboardingCheckout, activateFreeTier } from "../../api/stripe";
-import { createAlert } from "../../api/alerts";
-import {
-  updateNotificationConfig,
-  testNotificationChannels,
-} from "../../api/notificationConfig";
-import { createCheckoutSession, getSubscriptionStatus, verifyCheckoutSession } from "../../api/stripe";
 import Input from "../../components/Input";
 import Button from "../../components/Button";
+import TierPicker from "../../components/TierPicker";
 import "./Subscribe.css";
 
-const STEPS = [
+const STEPS = ["Create Account", "Choose Plan"];
-  "Create Account",
-  "Add Wallet",
-  "Alert Rules",
-  "Notifications",
-  "Done",
-];
 
 export default function Subscribe() {
-  const { currentUser, signup } = useAuth();
+  const { isAuthenticated, register } = useAuth();
   const navigate = useNavigate();
   const [searchParams, setSearchParams] = useSearchParams();
 
-  const [step, setStep] = useState(1);
+  const hasPaymentReturn = searchParams.get("payment") === "success";
-  const [loading, setLoading] = useState(false);
+  const [step, setStep] = useState(hasPaymentReturn || isAuthenticated ? 2 : 1);
+  const [loading, setLoading] = useState(hasPaymentReturn);
   const [error, setError] = useState("");
-  const [skipWarning, setSkipWarning] = useState("");
-  const [testResults, setTestResults] = useState(null);
-  const [testLoading, setTestLoading] = useState(false);
 
   const [data, setData] = useState({
+    selectedTier: "",
     email: "",
     password: "",
     confirmPassword: "",
-    walletAddress: "",
-    walletLabel: "",
-    createdAddressId: null,
-    alertIncomingTx: false,
-    alertOutgoingTx: false,
-    alertLargeTransfer: false,
-    largeTransferThreshold: "",
-    alertBalanceBelow: false,
-    balanceBelowThreshold: "",
-    discordWebhookUrl: "",
-    slackWebhookUrl: "",
-    notificationEmail: "",
-    alertsCreated: [],
-    notificationConfigured: false,
   });
 
+  const registerCalledRef = useRef(false);
+
   function set(field, value) {
     setData((prev) => ({ ...prev, [field]: value }));
   }
 
+  // Handle return from Stripe checkout redirect.
+  // The ref guard prevents React StrictMode from double-firing this.
   useEffect(() => {
-    if (!currentUser) return;
+    if (registerCalledRef.current) return;
-    getAddresses()
-      .then((addresses) => {
-        if (addresses.length > 0) {
-          navigate("/addresses", { replace: true });
-        }
-      })
-      .catch(() => { });
-  }, [currentUser, navigate]);
 
-  // Handle Stripe redirect back from checkout
-  useEffect(() => {
-    if (!currentUser) return;
     const payment = searchParams.get("payment");
     const sessionId = searchParams.get("session_id");
-    if (payment === "success" && sessionId) {
+
+    if (payment === "cancelled") {
       setSearchParams({}, { replace: true });
-      setLoading(true);
+      setStep(2);
-      verifyCheckoutSession(sessionId)
-        .then(() => {
-          setStep(2);
-        })
-        .catch((err) => {
-          setError("Payment verification failed: " + err.message);
-          setStep(1);
-        })
-        .finally(() => setLoading(false));
-    } else if (payment === "cancelled") {
-      setSearchParams({}, { replace: true });
-      setStep(1);
       setError("Payment was cancelled. Please try again.");
+      return;
     }
-  }, [currentUser, searchParams, setSearchParams]);
+
+    if (payment !== "success" || !sessionId) return;
+
+    const savedEmail = sessionStorage.getItem("kp_onboard_email");
+    const savedPassword = sessionStorage.getItem("kp_onboard_password");
+
+    if (!savedEmail || !savedPassword) {
+      setSearchParams({}, { replace: true });
+      setError("Session expired. Please start the signup process again.");
+      setStep(1);
+      setLoading(false);
+      return;
+    }
+
+    registerCalledRef.current = true;
+    setSearchParams({}, { replace: true });
+    setLoading(true);
+
+    register(savedEmail, savedPassword, sessionId)
+      .then(() => {
+        sessionStorage.removeItem("kp_onboard_email");
+        sessionStorage.removeItem("kp_onboard_password");
+        navigate("/addresses", { replace: true });
+      })
+      .catch((err) => {
+        registerCalledRef.current = false;
+        setError("Registration failed: " + err.message);
+        setStep(1);
+      })
+      .finally(() => setLoading(false));
+  }, []); // eslint-disable-line react-hooks/exhaustive-deps
 
   // ── Step handlers ─────────────────────────────────────────────────────────
 
-  async function handleStep1() {
+  function handleStep1() {
     setError("");
     if (!data.email || !data.password || !data.confirmPassword) {
       setError("Please fill in all fields");
@@ -107,136 +94,48 @@ export default function Subscribe() {
       setError("Password must be at least 6 characters");
       return;
     }
-    try {
+    setStep(2);
-      setLoading(true);
-      if (!currentUser) {
-        await signup(data.email, data.password);
-      }
-      const status = await getSubscriptionStatus();
-      if (status.subscription_status === "active" || status.subscription_status === "trialing") {
-        setStep(2);
-        return;
-      }
-      const { url } = await createCheckoutSession();
-      window.location.href = url;
-    } 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);
-    }
   }
 
   async function handleStep2() {
     setError("");
-    if (!data.walletAddress) {
+    if (!data.selectedTier) {
-      setError("Please enter a wallet address");
+      setError("Please select a plan to continue");
-      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() {
+      // Free tier: register immediately, then activate free tier
-    setError("");
+      if (data.selectedTier === "free") {
-    const rules = [];
+        if (!isAuthenticated) {
-    if (data.alertIncomingTx) rules.push({ type: "incoming_tx" });
+          await register(data.email, data.password, "");
-    if (data.alertOutgoingTx) rules.push({ type: "outgoing_tx" });
+        }
-    if (data.alertLargeTransfer) {
+        await activateFreeTier();
-      if (!data.largeTransferThreshold) {
+        navigate("/addresses", { replace: true });
-        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) {
+      // Paid tier: stash credentials in sessionStorage, then redirect to Stripe
-      setStep(4);
+      sessionStorage.setItem("kp_onboard_email", data.email);
-      return;
+      sessionStorage.setItem("kp_onboard_password", data.password);
-    }
 
-    try {
+      const { url } = await createOnboardingCheckout(
-      setLoading(true);
+        data.email,
-      const created = [];
+        data.selectedTier,
-      for (const rule of rules) {
+      );
-        const result = await createAlert(data.createdAddressId, rule);
+      window.location.href = url;
-        created.push(result);
-      }
-      set("alertsCreated", created);
-      setStep(4);
     } catch (err) {
-      setError(err.message);
+      if (err.message.includes("already exists")) {
+        setError("An account with this email already exists. Try logging in instead.");
+      } else {
+        setError("Failed to process plan selection: " + 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() {
@@ -256,10 +155,11 @@ export default function Subscribe() {
             <div key={label} className="progress-bar__step">
               {i > 0 && (
                 <div
-                  className={`progress-bar__connector ${done || active
+                  className={`progress-bar__connector ${
-                    ? "progress-bar__connector--active"
+                    done || active
-                    : "progress-bar__connector--inactive"
+                      ? "progress-bar__connector--active"
-                    }`}
+                      : "progress-bar__connector--inactive"
+                  }`}
                 />
               )}
               <div>
@@ -267,10 +167,11 @@ export default function Subscribe() {
                   {done ? "\u2713" : stepNum}
                 </div>
                 <div
-                  className={`progress-bar__label ${active
+                  className={`progress-bar__label ${
-                    ? "progress-bar__label--active"
+                    active
-                    : "progress-bar__label--inactive"
+                      ? "progress-bar__label--active"
-                    }`}
+                      : "progress-bar__label--inactive"
+                  }`}
                 >
                   {label}
                 </div>
@@ -284,7 +185,7 @@ export default function Subscribe() {
 
   // ── Step content ──────────────────────────────────────────────────────────
 
-  function Step1() {
+  function StepCreateAccount() {
     return (
       <>
         <h2 className="mb-lg">Create your account</h2>
@@ -317,314 +218,60 @@ export default function Subscribe() {
     );
   }
 
-  function Step2() {
+  function StepChoosePlan() {
     return (
       <>
-        <h2 className="mb-sm">Add a wallet address</h2>
+        <h2 className="mb-sm">Choose your monitoring plan</h2>
         <p className="subscribe__subtitle">
-          Enter the Ethereum address you want to monitor.
+          Select the plan that works best for you. You can upgrade anytime.
         </p>
-        <Input
+        <TierPicker
-          label="ETH Address"
+          onSelect={(tier) => set("selectedTier", tier)}
-          value={data.walletAddress}
+          selectedTier={data.selectedTier}
-          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="subscribe__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="subscribe__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="subscribe__summary">
-          <p className="subscribe__summary-title">Summary</p>
-          <ul className="subscribe__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 > 2;
-
     async function handleNext() {
-      setSkipWarning("");
+      if (step === 1) handleStep1();
-      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);
     }
 
-    const nextLabel = step === 1
+    const nextLabel =
-      ? "Create Account & Subscribe"
+      step === 1
-      : step === 4
+        ? "Create Account"
-        ? "Finish"
+        : !data.selectedTier
-        : "Next →";
+          ? "Continue"
+          : data.selectedTier === "free"
+            ? "Start Free Trial"
+            : "Subscribe & Continue";
 
     return (
       <div className="subscribe__footer">
         <div>
-          {canBack && (
+          {step === 2 && !isAuthenticated && (
-            <Button
+            <Button onClick={handleBack} disabled={loading} variant="ghost">
-              onClick={handleBack}
-              disabled={loading}
-              variant="ghost"
-            >
               ← Back
             </Button>
           )}
         </div>
 
-        <div className="flex gap-md">
+        <Button
-          {canSkip && (
+          onClick={handleNext}
-            <Button
+          disabled={loading || (step === 2 && !data.selectedTier)}
-              onClick={handleSkip}
+          className="text-bold"
-              disabled={loading}
+        >
-              variant="ghost"
+          {loading ? "Please wait..." : nextLabel}
-            >
+        </Button>
-              Skip for now
-            </Button>
-          )}
-          <Button
-            onClick={handleNext}
-            disabled={loading}
-            className="text-bold"
-          >
-            {loading ? "Please wait..." : nextLabel}
-          </Button>
-        </div>
       </div>
     );
   }
@@ -632,27 +279,20 @@ export default function Subscribe() {
   // ── Render ────────────────────────────────────────────────────────────────
 
   const stepContent = {
-    1: Step1(),
+    1: StepCreateAccount(),
-    2: Step2(),
+    2: StepChoosePlan(),
-    3: Step3(),
-    4: Step4(),
-    5: Step5(),
   };
 
   return (
     <div className="subscribe">
-      <div className="subscribe__container">
+      <div
+        className={`subscribe__container${step === 2 ? " subscribe__container--wide" : ""}`}
+      >
         <h1 className="subscribe__title">Koin Ping</h1>
 
         {ProgressBar()}
 
-        {error && (
+        {error && <div className="alert alert--error">{error}</div>}
-          <div className="alert alert--error">{error}</div>
-        )}
-
-        {skipWarning && (
-          <div className="alert alert--warning">{skipWarning}</div>
-        )}
 
         <div className="subscribe__card">
           {stepContent[step]}
@@ -661,8 +301,7 @@ export default function Subscribe() {
 
         {step === 1 && (
           <p className="subscribe__login-link">
-            Already have an account?{" "}
+            Already have an account? <a href="/login">Log in here</a>
-            <a href="/login">Log in here</a>
           </p>
         )}
       </div>

frontend/src/pages/user_account/Account.jsx

@@ -1,10 +1,16 @@
 import { useState, useEffect } from "react";
-import { updatePassword } from "firebase/auth";
+import { useNavigate } from "react-router-dom";
-import { auth } from "../../firebase/config";
 import { getAccount, createPortalSession } from "../../api/account";
 import "./Account.css";
 
+const TIER_LABELS = {
+  free: "Free Trial",
+  premium: "Premium",
+  pro: "Pro",
+};
+
 export default function Account() {
+  const navigate = useNavigate();
   const [account, setAccount] = useState(null);
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState(null);
@@ -47,7 +53,8 @@ export default function Account() {
 
     try {
       setChangingPassword(true);
-      await updatePassword(auth.currentUser, newPassword);
+      // TODO: implement password change endpoint on backend
+      throw new Error("Password change not yet implemented");
       setPasswordMsg("Password updated successfully");
       setNewPassword("");
       setConfirmPassword("");
@@ -78,6 +85,7 @@ export default function Account() {
     return <div className="page text-error">Error: {error}</div>;
   }
 
+  const tier = account.subscription_tier || "free";
   const isCanceling = account.cancel_at_period_end;
   const statusLabel = isCanceling
     ? "Canceling"
@@ -86,6 +94,9 @@ export default function Account() {
       : account.subscription_status.charAt(0).toUpperCase() +
         account.subscription_status.slice(1);
 
+  const canUpgrade = tier === "free" || tier === "premium";
+  const hasPaidSub = tier !== "free";
+
   return (
     <div className="page account-page">
       <h1 className="mb-lg">Account</h1>
@@ -114,7 +125,7 @@ export default function Account() {
         <h2 className="account__section-title">Subscription</h2>
         <div className="account__row">
           <span className="account__label">Plan</span>
-          <span className="account__value">{account.subscription_plan}</span>
+          <span className="account__value">{TIER_LABELS[tier] || account.subscription_plan}</span>
         </div>
         <div className="account__row">
           <span className="account__label">Status</span>
@@ -149,15 +160,27 @@ export default function Account() {
         )}
 
         <div className="account__portal-section">
-          <button
+          {canUpgrade && (
-            onClick={handleManageSubscription}
+            <button
-            disabled={portalLoading}
+              onClick={() => navigate("/subscribe")}
-            className="btn btn--ghost"
+              className="btn btn--primary"
-          >
+            >
-            {portalLoading ? "Redirecting..." : "Manage Subscription"}
+              Upgrade Plan
-          </button>
+            </button>
+          )}
+          {hasPaidSub && (
+            <button
+              onClick={handleManageSubscription}
+              disabled={portalLoading}
+              className="btn btn--ghost"
+            >
+              {portalLoading ? "Redirecting..." : "Manage Subscription"}
+            </button>
+          )}
           <p className="text-dimmed text-sm account__portal-hint">
-            Cancel subscription, update payment method, or view invoices via Stripe.
+            {hasPaidSub
+              ? "Cancel subscription, update payment method, or view invoices via Stripe."
+              : "Upgrade to unlock more addresses, alert types, and notification channels."}
           </p>
         </div>
       </div>

frontend/src/reducers/authReducer.jsx

@@ -0,0 +1,56 @@
+export const ACTION_TYPES = {
+  LOGIN_SUCCESS: "LOGIN_SUCCESS",
+  SET_USER: "SET_USER",
+  LOGOUT: "LOGOUT",
+  AUTH_ERROR: "AUTH_ERROR",
+};
+
+export const initialState = {
+  user: null,
+  token: localStorage.getItem("kp_token") || null,
+  isAuthenticated: !!localStorage.getItem("kp_token"),
+  error: null,
+};
+
+export default function authReducer(state, action) {
+  switch (action.type) {
+    case ACTION_TYPES.LOGIN_SUCCESS:
+      localStorage.setItem("kp_token", action.payload.token);
+      return {
+        ...state,
+        user: {
+          id: action.payload.user_id,
+          email: action.payload.email,
+          subscriptionStatus: action.payload.subscription_status,
+          subscriptionTier: action.payload.subscription_tier,
+        },
+        token: action.payload.token,
+        isAuthenticated: true,
+        error: null,
+      };
+
+    case ACTION_TYPES.SET_USER:
+      return {
+        ...state,
+        user: action.payload,
+        error: null,
+      };
+
+    case ACTION_TYPES.LOGOUT:
+      localStorage.removeItem("kp_token");
+      return {
+        ...initialState,
+        token: null,
+        isAuthenticated: false,
+      };
+
+    case ACTION_TYPES.AUTH_ERROR:
+      return {
+        ...state,
+        error: action.payload,
+      };
+
+    default:
+      return state;
+  }
+}