m

Setup free tier

.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 +1,32 @@
-Start DB:
+Backend startup quickstarat:
+----------------------------->  BEST
+## 1. brew services start postgresql@15
 
-brew services start postgresql@15
+          OR 
 
-From the backend directory, you have a few options:
+      /opt/homebrew/opt/postgresql@15/bin/pg_ctl -D /opt/homebrew/var/postgresql@15 start
 
-Option 1: Single command (both API + poller)
+## 2.   ALLIN ONE: 
-cd /Users/kjannette/workspace/koin_ping_0.2.0/backendmake dev-all
+        Make dev-all — Runs both the API and poller concurrently.
+----------------------------->  BEST
 
-Option 2: Two separate terminals
+          - OR - 
-Terminal 1 (API server):
+          
-cd /Users/kjannette/workspace/koin_ping_0.2.0/backend go run ./cmd/api
+           
-Terminal 2 (Poller):
+## 3.  Option 1: Single command (both API + poller)
-cd /Users/kjannette/workspace/koin_ping_0.2.0/backend go run ./cmd/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

@@ -55,14 +55,14 @@ 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)
 
 	authenticate := middleware.Authenticate(userModel)
 	requireSub := middleware.RequireSubscription(userModel)
@@ -82,6 +82,9 @@ func main() {
 	// 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/infra/migrations/009_add_subscription_tier.sql

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

backend/infra/schema.sql

@@ -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 +32,12 @@ 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
 }
 
 // Load reads configuration from environment variables and returns a Config.
@@ -57,10 +58,11 @@ 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"),
 	}
 
@@ -92,6 +94,19 @@ func (c *Config) DSN() string {
 	)
 }
 
+// TierForPriceID maps a Stripe price ID back to the corresponding
+// subscription tier. Returns empty string if the price is unrecognised.
+func (c *Config) TierForPriceID(priceID string) string {
+	switch priceID {
+	case c.StripePriceIDPremium:
+		return "premium"
+	case c.StripePriceIDPro:
+		return "pro"
+	default:
+		return ""
+	}
+}
+
 func getEnv(key, fallback string) string {
 	if v := os.Getenv(key); v != "" {
 		return v

backend/internal/config/config_test.go

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

backend/internal/domain/types.go

@@ -2,17 +2,77 @@ package domain
 
 import "time"
 
+type SubscriptionTier string
+
+const (
+	TierFree    SubscriptionTier = "free"
+	TierPremium SubscriptionTier = "premium"
+	TierPro     SubscriptionTier = "pro"
+)
+
+func IsValidTier(t string) bool {
+	switch SubscriptionTier(t) {
+	case TierFree, TierPremium, TierPro:
+		return true
+	}
+	return false
+}
+
+const unlimitedLimit = -1
+
+type TierLimits struct {
+	MaxAddresses    int      `json:"max_addresses"`
+	MaxAlertTypes   int      `json:"max_alert_types"`
+	AllowedChannels []string `json:"allowed_channels"`
+}
+
+func GetTierLimits(tier SubscriptionTier) TierLimits {
+	switch tier {
+	case TierPremium:
+		return TierLimits{
+			MaxAddresses:    3,
+			MaxAlertTypes:   2,
+			AllowedChannels: []string{"email", "discord", "telegram"},
+		}
+	case TierPro:
+		return TierLimits{
+			MaxAddresses:    unlimitedLimit,
+			MaxAlertTypes:   unlimitedLimit,
+			AllowedChannels: []string{"email", "discord", "telegram", "slack"},
+		}
+	default:
+		return TierLimits{
+			MaxAddresses:    1,
+			MaxAlertTypes:   1,
+			AllowedChannels: []string{"email"},
+		}
+	}
+}
+
+func (l TierLimits) IsUnlimitedAddresses() bool  { return l.MaxAddresses == unlimitedLimit }
+func (l TierLimits) IsUnlimitedAlertTypes() bool  { return l.MaxAlertTypes == unlimitedLimit }
+
+func (l TierLimits) ChannelAllowed(channel string) bool {
+	for _, c := range l.AllowedChannels {
+		if c == channel {
+			return true
+		}
+	}
+	return false
+}
+
 type User struct {
-	ID                    string     `json:"id"`
+	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:"-"`
+	StripeCustomerID      *string          `json:"-"`
-	StripeSubscriptionID  *string    `json:"-"`
+	StripeSubscriptionID  *string          `json:"-"`
-	SubscriptionStatus    string     `json:"subscription_status"`    //nolint:tagliatelle
+	SubscriptionStatus    string           `json:"subscription_status"`    //nolint:tagliatelle
-	SubscriptionCreatedAt *time.Time `json:"subscription_created_at,omitempty"` //nolint:tagliatelle
+	SubscriptionTier      SubscriptionTier `json:"subscription_tier"`      //nolint:tagliatelle
-	CreatedAt             time.Time  `json:"created_at"`             //nolint:tagliatelle
+	SubscriptionCreatedAt *time.Time       `json:"subscription_created_at,omitempty"` //nolint:tagliatelle
-	UpdatedAt             time.Time  `json:"updated_at"`             //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/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 +145,7 @@ func (h *StripeHandler) VerifyCheckoutSession(w http.ResponseWriter, r *http.Req
 		return
 	}
 
-	if s.ClientReferenceID != userID {
+	if s.ClientReferenceID != "" && s.ClientReferenceID != userID {
 		writeError(w, http.StatusForbidden, "FORBIDDEN", "Session does not belong to this user")
 		return
 	}
@@ -116,6 +155,11 @@ 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 +175,92 @@ 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
+	}
+
+	writeJSON(w, http.StatusOK, map[string]string{"url": s.URL})
 }
 
 // CreatePortalSession creates a Stripe Billing Portal session so the user can
@@ -173,7 +296,6 @@ 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 {
@@ -217,6 +339,11 @@ 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 +360,12 @@ 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 +384,26 @@ 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

@@ -17,6 +17,7 @@ type contextKey string
 const (
 	UserIDKey    contextKey = "user_id"
 	UserEmailKey contextKey = "user_email"
+	UserTierKey  contextKey = "user_tier"
 )
 
 type errorResponse struct {
@@ -94,6 +95,7 @@ func Authenticate(userModel *models.UserModel) func(http.Handler) http.Handler {
 
 			ctx := context.WithValue(r.Context(), UserIDKey, user.ID)
 			ctx = context.WithValue(ctx, UserEmailKey, email)
+			ctx = context.WithValue(ctx, UserTierKey, string(user.SubscriptionTier))
 
 			next.ServeHTTP(w, r.WithContext(ctx))
 		})
@@ -150,3 +152,10 @@ func GetUserEmail(ctx context.Context) string {
 	}
 	return ""
 }
+
+func GetUserTier(ctx context.Context) string {
+	if v, ok := ctx.Value(UserTierKey).(string); ok {
+		return v
+	}
+	return "free"
+}

backend/internal/middleware/auth_test.go

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

backend/internal/models/address.go

@@ -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

@@ -19,14 +19,14 @@ func NewUserModel(pool *pgxpool.Pool) *UserModel {
 
 const userColumns = `id, firebase_uid, email, display_name,
 	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.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) {
@@ -66,15 +66,37 @@ 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

@@ -10,7 +10,7 @@ import AlertHistory from "./pages/alertHistory/AlertHistory";
 import Account from "./pages/user_account/Account";
 
 export default function App() {
-  const { currentUser } = useAuth();
+  const { currentUser, isSubscribed } = useAuth();
 
   if (!currentUser) {
     return (
@@ -23,6 +23,16 @@ export default function App() {
     );
   }
 
+  if (!isSubscribed) {
+    return (
+      <Routes>
+        <Route path="/subscribe" element={<Subscribe />} />
+        <Route path="/account" element={<><Navbar /><Account /></>} />
+        <Route path="*" element={<Navigate to="/subscribe" />} />
+      </Routes>
+    );
+  }
+
   return (
     <div>
       <Navbar />

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/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 +1,96 @@
+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: [
+      "Real-time Discord alerts",
+      "Real-time Telegram alerts",
+      "Real-time Slack alerts",
+    ],
+  },
+  {
+    id: "premium",
+    name: "Premium Monitoring",
+    price: "$1.99",
+    period: "/month",
+    features: [
+      "Monitor 3 blockchain addresses",
+      "Configure alerts to fire on trigger events",
+      "Daily email digest alert",
+      "Real-time Discord alerts",
+      "Real-time Telegram alerts",
+      "2 transaction alert types per monitored address",
+    ],
+    disabledFeatures: [
+      "Real-time Slack alerts",
+    ],
+    highlighted: true,
+  },
+  {
+    id: "pro",
+    name: "Professional Monitoring",
+    price: "$11.99",
+    period: "/month",
+    features: [
+      "Monitor unlimited blockchain addresses",
+      "Configure alerts to fire on trigger events",
+      "Daily email digest alert",
+      "Real-time Discord alerts",
+      "Real-time Telegram alerts",
+      "Real-time Slack alerts",
+      "Unlimited transaction alert types per monitored address",
+    ],
+    disabledFeatures: [],
+  },
+];
+
+export default function TierPicker({ onSelect, selectedTier }) {
+  return (
+    <div className="tier-picker">
+      {TIERS.map((tier) => (
+        <div
+          key={tier.id}
+          className={`tier-picker__card${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

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

frontend/src/index.css

@@ -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/subscribe/Subscribe.css

@@ -15,6 +15,10 @@
   padding: 0 1rem;
 }
 
+.subscribe__container--wide {
+  max-width: 920px;
+}
+
 .subscribe__title {
   text-align: center;
   margin-bottom: 2rem;
@@ -237,6 +241,29 @@
   font-style: italic;
 }
 
+/* Tier limit hints */
+.subscribe__tier-hint {
+  font-size: 0.82rem;
+  color: #ffcc44;
+  margin-top: 0.5rem;
+}
+
+/* Disabled channel group */
+.subscribe__channel-disabled {
+  opacity: 0.5;
+  pointer-events: none;
+}
+
+.subscribe__channel-disabled .subscribe__tier-hint {
+  pointer-events: auto;
+  opacity: 1;
+}
+
+/* Disabled checkbox row */
+.checkbox-row--disabled {
+  opacity: 0.5;
+}
+
 /* ── Subscribe Responsive ────────────────────────────────── */
 
 @media (max-width: 480px) {

frontend/src/pages/subscribe/Subscribe.jsx

@@ -7,13 +7,21 @@ import {
   updateNotificationConfig,
   testNotificationChannels,
 } from "../../api/notificationConfig";
-import { createCheckoutSession, getSubscriptionStatus, verifyCheckoutSession } from "../../api/stripe";
+import { createOnboardingCheckout, verifyCheckoutSession, activateFreeTier } from "../../api/stripe";
 import Input from "../../components/Input";
 import Button from "../../components/Button";
+import TierPicker from "../../components/TierPicker";
 import "./Subscribe.css";
 
+const TIER_LIMITS = {
+  free:    { maxAlertTypes: 1, channels: ["email"] },
+  premium: { maxAlertTypes: 2, channels: ["email", "discord", "telegram"] },
+  pro:     { maxAlertTypes: 4, channels: ["email", "discord", "telegram", "slack"] },
+};
+
 const STEPS = [
   "Create Account",
+  "Choose Plan",
   "Add Wallet",
   "Alert Rules",
   "Notifications",
@@ -25,14 +33,17 @@ export default function Subscribe() {
   const navigate = useNavigate();
   const [searchParams, setSearchParams] = useSearchParams();
 
-  const [step, setStep] = useState(1);
+  const hasPaymentReturn = searchParams.get("payment") === "success";
-  const [loading, setLoading] = useState(false);
+  const isUpgrade = searchParams.get("upgrade") === "true";
+  const [step, setStep] = useState(hasPaymentReturn || currentUser ? 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: "",
@@ -56,8 +67,10 @@ export default function Subscribe() {
     setData((prev) => ({ ...prev, [field]: value }));
   }
 
+  const tierLimits = TIER_LIMITS[data.selectedTier] || TIER_LIMITS.free;
+
   useEffect(() => {
-    if (!currentUser) return;
+    if (!currentUser || isUpgrade) return;
     getAddresses()
       .then((addresses) => {
         if (addresses.length > 0) {
@@ -65,35 +78,64 @@ export default function Subscribe() {
         }
       })
       .catch(() => { });
-  }, [currentUser, navigate]);
+  }, [currentUser, navigate, isUpgrade]);
 
-  // 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;
+
+    // Phase 1: no account yet — create it. This triggers an auth state change
+    // which remounts the component (App.jsx swaps route trees). The URL params
+    // are preserved so Phase 2 runs on the next mount.
+    if (!currentUser) {
+      const savedEmail = sessionStorage.getItem("kp_onboard_email");
+      const savedPw = sessionStorage.getItem("kp_onboard_pw");
+      if (!savedEmail || !savedPw) {
+        setSearchParams({}, { replace: true });
+        setError("Session expired. Please start the signup process again.");
+        setStep(1);
+        setLoading(false);
+        return;
+      }
+      setLoading(true);
+      signup(savedEmail, savedPw).catch((err) => {
+        setSearchParams({}, { replace: true });
+        setError("Account creation failed: " + err.message);
+        setStep(1);
+        setLoading(false);
+      });
+      return;
+    }
+
+    // Phase 2: authenticated — verify the checkout and activate subscription.
+    setSearchParams({}, { replace: true });
+    setLoading(true);
+    sessionStorage.removeItem("kp_onboard_email");
+    sessionStorage.removeItem("kp_onboard_pw");
+
+    verifyCheckoutSession(sessionId)
+      .then(() => {
+        setStep(3);
+      })
+      .catch((err) => {
+        setError("Payment verification failed: " + err.message);
+        setStep(2);
+      })
+      .finally(() => setLoading(false));
+  }, [currentUser, searchParams, setSearchParams, signup]);
 
   // ── Step handlers ─────────────────────────────────────────────────────────
 
-  async function handleStep1() {
+  function handleStep1() {
     setError("");
     if (!data.email || !data.password || !data.confirmPassword) {
       setError("Please fill in all fields");
@@ -107,17 +149,30 @@ export default function Subscribe() {
       setError("Password must be at least 6 characters");
       return;
     }
+    setStep(2);
+  }
+
+  async function handleStep2() {
+    setError("");
+    if (!data.selectedTier) {
+      setError("Please select a plan to continue");
+      return;
+    }
     try {
       setLoading(true);
-      if (!currentUser) {
+
-        await signup(data.email, data.password);
+      if (data.selectedTier === "free") {
-      }
+        if (!currentUser) {
-      const status = await getSubscriptionStatus();
+          await signup(data.email, data.password);
-      if (status.subscription_status === "active" || status.subscription_status === "trialing") {
+        }
-        setStep(2);
+        await activateFreeTier();
+        setStep(3);
         return;
       }
-      const { url } = await createCheckoutSession();
+
+      sessionStorage.setItem("kp_onboard_email", data.email);
+      sessionStorage.setItem("kp_onboard_pw", data.password);
+      const { url } = await createOnboardingCheckout(data.email, data.selectedTier);
       window.location.href = url;
     } catch (err) {
       if (err.code === "auth/email-already-in-use") {
@@ -127,13 +182,14 @@ export default function Subscribe() {
       } else if (err.code === "auth/weak-password") {
         setError("Password is too weak");
       } else {
-        setError("Failed to create account: " + err.message);
+        setError("Failed to process plan selection: " + err.message);
       }
+    } finally {
       setLoading(false);
     }
   }
 
-  async function handleStep2() {
+  async function handleStep3() {
     setError("");
     if (!data.walletAddress) {
       setError("Please enter a wallet address");
@@ -150,7 +206,7 @@ export default function Subscribe() {
         label: data.walletLabel || undefined,
       });
       set("createdAddressId", created.id);
-      setStep(3);
+      setStep(4);
     } catch (err) {
       setError(err.message);
     } finally {
@@ -158,7 +214,7 @@ export default function Subscribe() {
     }
   }
 
-  async function handleStep3() {
+  async function handleStep4() {
     setError("");
     const rules = [];
     if (data.alertIncomingTx) rules.push({ type: "incoming_tx" });
@@ -179,7 +235,7 @@ export default function Subscribe() {
     }
 
     if (rules.length === 0) {
-      setStep(4);
+      setStep(5);
       return;
     }
 
@@ -191,7 +247,7 @@ export default function Subscribe() {
         created.push(result);
       }
       set("alertsCreated", created);
-      setStep(4);
+      setStep(5);
     } catch (err) {
       setError(err.message);
     } finally {
@@ -199,12 +255,12 @@ export default function Subscribe() {
     }
   }
 
-  async function handleStep4() {
+  async function handleStep5() {
     setError("");
     const hasAny =
       data.discordWebhookUrl || data.slackWebhookUrl || data.notificationEmail;
     if (!hasAny) {
-      setStep(5);
+      setStep(6);
       return;
     }
     try {
@@ -216,7 +272,7 @@ export default function Subscribe() {
         email: data.notificationEmail || undefined,
       });
       set("notificationConfigured", true);
-      setStep(5);
+      setStep(6);
     } catch (err) {
       setError(err.message);
     } finally {
@@ -237,6 +293,21 @@ export default function Subscribe() {
     }
   }
 
+  // ── Alert type limit helpers ──────────────────────────────────────────────
+
+  function countSelectedAlerts() {
+    let count = 0;
+    if (data.alertIncomingTx) count++;
+    if (data.alertOutgoingTx) count++;
+    if (data.alertLargeTransfer) count++;
+    if (data.alertBalanceBelow) count++;
+    return count;
+  }
+
+  function canSelectMoreAlerts() {
+    return tierLimits.maxAlertTypes > countSelectedAlerts();
+  }
+
   // ── Progress bar ──────────────────────────────────────────────────────────
 
   function ProgressBar() {
@@ -284,7 +355,7 @@ export default function Subscribe() {
 
   // ── Step content ──────────────────────────────────────────────────────────
 
-  function Step1() {
+  function StepCreateAccount() {
     return (
       <>
         <h2 className="mb-lg">Create your account</h2>
@@ -317,7 +388,22 @@ export default function Subscribe() {
     );
   }
 
-  function Step2() {
+  function StepChoosePlan() {
+    return (
+      <>
+        <h2 className="mb-sm">Choose your monitoring plan</h2>
+        <p className="subscribe__subtitle">
+          Select the plan that works best for you. You can upgrade anytime.
+        </p>
+        <TierPicker
+          onSelect={(tier) => set("selectedTier", tier)}
+          selectedTier={data.selectedTier}
+        />
+      </>
+    );
+  }
+
+  function StepAddWallet() {
     return (
       <>
         <h2 className="mb-sm">Add a wallet address</h2>
@@ -343,28 +429,35 @@ export default function Subscribe() {
     );
   }
 
-  function Step3() {
+  function StepAlertRules() {
+    const atLimit = !canSelectMoreAlerts();
+    const maxTypes = tierLimits.maxAlertTypes;
+
     return (
       <>
         <h2 className="mb-sm">Configure alert rules</h2>
         <p className="subscribe__subtitle">
-          Choose which events trigger notifications. You can change these later.
+          Choose which events trigger notifications ({countSelectedAlerts()}/{maxTypes} selected).
+          You can change these later.
         </p>
 
         <CheckboxRow
           checked={data.alertIncomingTx}
           onChange={(v) => set("alertIncomingTx", v)}
           label="Incoming transaction"
+          disabled={!data.alertIncomingTx && atLimit}
         />
         <CheckboxRow
           checked={data.alertOutgoingTx}
           onChange={(v) => set("alertOutgoingTx", v)}
           label="Outgoing transaction"
+          disabled={!data.alertOutgoingTx && atLimit}
         />
         <CheckboxRow
           checked={data.alertLargeTransfer}
           onChange={(v) => set("alertLargeTransfer", v)}
           label="Large transfer"
+          disabled={!data.alertLargeTransfer && atLimit}
         >
           {data.alertLargeTransfer && (
             <div className="checkbox-row__nested">
@@ -384,6 +477,7 @@ export default function Subscribe() {
           checked={data.alertBalanceBelow}
           onChange={(v) => set("alertBalanceBelow", v)}
           label="Balance below"
+          disabled={!data.alertBalanceBelow && atLimit}
         >
           {data.alertBalanceBelow && (
             <div className="checkbox-row__nested">
@@ -399,11 +493,21 @@ export default function Subscribe() {
             </div>
           )}
         </CheckboxRow>
+
+        {atLimit && data.selectedTier !== "pro" && (
+          <p className="subscribe__tier-hint">
+            Your {data.selectedTier} plan allows {maxTypes} alert type{maxTypes !== 1 ? "s" : ""} per address. Upgrade for more.
+          </p>
+        )}
       </>
     );
   }
 
-  function Step4() {
+  function StepNotifications() {
+    const channels = tierLimits.channels;
+    const canDiscord = channels.includes("discord");
+    const canSlack = channels.includes("slack");
+
     return (
       <>
         <h2 className="mb-sm">Set up notifications</h2>
@@ -411,7 +515,17 @@ export default function Subscribe() {
           Add at least one channel so you receive alerts. All fields are optional.
         </p>
 
-        <div className="mb-md">
+        <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"
+        />
+
+        <div className={`mb-md${!canDiscord ? " subscribe__channel-disabled" : ""}`}>
           <label className="form-label">
             Discord Webhook URL{" "}
             <a
@@ -428,12 +542,15 @@ export default function Subscribe() {
             type="url"
             value={data.discordWebhookUrl}
             onChange={(v) => set("discordWebhookUrl", v)}
-            disabled={loading}
+            disabled={loading || !canDiscord}
             placeholder="https://discord.com/api/webhooks/..."
           />
+          {!canDiscord && (
+            <p className="subscribe__tier-hint">Upgrade to Premium to enable Discord alerts</p>
+          )}
         </div>
 
-        <div className="mb-md">
+        <div className={`mb-md${!canSlack ? " subscribe__channel-disabled" : ""}`}>
           <label className="form-label">
             Slack Webhook URL{" "}
             <a
@@ -450,25 +567,18 @@ export default function Subscribe() {
             type="url"
             value={data.slackWebhookUrl}
             onChange={(v) => set("slackWebhookUrl", v)}
-            disabled={loading}
+            disabled={loading || !canSlack}
             placeholder="https://hooks.slack.com/services/..."
           />
+          {!canSlack && (
+            <p className="subscribe__tier-hint">Upgrade to Pro to enable Slack alerts</p>
+          )}
         </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() {
+  function StepDone() {
     const alertCount = data.alertsCreated.length;
     const hasNotif = data.notificationConfigured;
 
@@ -479,6 +589,12 @@ export default function Subscribe() {
         <div className="subscribe__summary">
           <p className="subscribe__summary-title">Summary</p>
           <ul className="subscribe__summary-list">
+            <li>
+              Plan:{" "}
+              <span className="text-white">
+                {data.selectedTier === "pro" ? "Pro" : data.selectedTier === "premium" ? "Premium" : "Free Trial"}
+              </span>
+            </li>
             <li>
               Wallet address added:{" "}
               <span className="text-mono text-white-sm">
@@ -542,15 +658,16 @@ export default function Subscribe() {
 
   // ── Shared helpers ────────────────────────────────────────────────────────
 
-  function CheckboxRow({ checked, onChange, label, children }) {
+  function CheckboxRow({ checked, onChange, label, children, disabled }) {
     return (
-      <div className="checkbox-row">
+      <div className={`checkbox-row${disabled ? " checkbox-row--disabled" : ""}`}>
         <label className="checkbox-row__label">
           <input
             type="checkbox"
             checked={checked}
             onChange={(e) => onChange(e.target.checked)}
             className="checkbox-row__input"
+            disabled={disabled}
           />
           {label}
         </label>
@@ -562,17 +679,18 @@ export default function Subscribe() {
   // ── Footer navigation ─────────────────────────────────────────────────────
 
   function Footer() {
-    if (step === 5) return null;
+    if (step === 6) return null;
 
-    const canSkip = step === 3 || step === 4;
+    const canSkip = step === 4 || step === 5;
-    const canBack = step > 2;
+    const canBack = step > 1 && step <= 5;
 
     async function handleNext() {
       setSkipWarning("");
-      if (step === 1) await handleStep1();
+      if (step === 1) handleStep1();
       else if (step === 2) await handleStep2();
       else if (step === 3) await handleStep3();
       else if (step === 4) await handleStep4();
+      else if (step === 5) await handleStep5();
     }
 
     function handleSkip() {
@@ -588,10 +706,16 @@ export default function Subscribe() {
     }
 
     const nextLabel = step === 1
-      ? "Create Account & Subscribe"
+      ? "Create Account"
-      : step === 4
+      : step === 2
-        ? "Finish"
+        ? !data.selectedTier
-        : "Next →";
+          ? "Continue"
+          : data.selectedTier === "free"
+            ? "Start Free Trial"
+            : "Subscribe & Continue"
+        : step === 5
+          ? "Finish"
+          : "Next →";
 
     return (
       <div className="subscribe__footer">
@@ -619,7 +743,7 @@ export default function Subscribe() {
           )}
           <Button
             onClick={handleNext}
-            disabled={loading}
+            disabled={loading || (step === 2 && !data.selectedTier)}
             className="text-bold"
           >
             {loading ? "Please wait..." : nextLabel}
@@ -632,16 +756,17 @@ export default function Subscribe() {
   // ── Render ────────────────────────────────────────────────────────────────
 
   const stepContent = {
-    1: Step1(),
+    1: StepCreateAccount(),
-    2: Step2(),
+    2: StepChoosePlan(),
-    3: Step3(),
+    3: StepAddWallet(),
-    4: Step4(),
+    4: StepAlertRules(),
-    5: Step5(),
+    5: StepNotifications(),
+    6: StepDone(),
   };
 
   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()}

frontend/src/pages/user_account/Account.jsx

@@ -1,10 +1,18 @@
 import { useState, useEffect } from "react";
+import { useNavigate } from "react-router-dom";
 import { updatePassword } from "firebase/auth";
 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);
@@ -78,6 +86,7 @@ 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 +95,9 @@ 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 +126,7 @@ 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 +161,27 @@ 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>