Sauci/docs/subscription-system.md

Subscription & Premium System

This document explains how subscriptions and premium access work across the client, server, and database layers.

Overview

Sauci uses RevenueCat for subscription management with a multi-layer architecture:

┌─────────────────┐     ┌──────────────────┐     ┌─────────────────┐
│   Mobile App    │────▶│    RevenueCat    │────▶│  Supabase Edge  │
│  (RevenueCat    │     │     Service      │     │    Functions    │
│     SDK)        │◀────│                  │◀────│                 │
└─────────────────┘     └──────────────────┘     └─────────────────┘
                                                          │
                                                          ▼
                                                 ┌─────────────────┐
                                                 │    Database     │
                                                 │  (is_premium)   │
                                                 └─────────────────┘

Components

1. Client SDK (src/lib/revenuecat.ts)

The RevenueCatService class wraps the react-native-purchases SDK.

Platform Support:

• iOS: Full support with native SDK
• Android: Full support with native SDK. getApiKey() selects the Android key, com.android.vending.BILLING is declared in app.json, and the paywall has no platform gating. The backend is store-agnostic: the webhook passes event.store through unchanged, so PLAY_STORE events need no separate handling.
• Web/Expo Go: Gracefully disabled (returns defaults)

Key Methods:

Method	Purpose
initialize(userId)	Configure SDK with API key and user ID
login(userId)	Associate purchases with Supabase user
getOfferings()	Fetch available subscription packages
purchasePackage(pkg)	Initiate purchase flow
restorePurchases()	Restore previous purchases
getCustomerInfo()	Get current subscription status
parseCustomerInfo()	Convert to SubscriptionState

Entitlement Check:

const entitlement = customerInfo.entitlements.active[ENTITLEMENT_ID];
return {
    isProUser: !!entitlement,
    activeSubscription: entitlement?.productIdentifier || null,
    expirationDate: entitlement?.expirationDate ? new Date(...) : null,
    willRenew: entitlement?.willRenew || false,
};

2. Zustand Store (src/store/index.ts)

The useSubscriptionStore manages subscription state in the app:

interface SubscriptionStoreState {
    subscription: SubscriptionState;
    offerings: PurchasesOffering | null;
    isLoadingOfferings: boolean;
    isPurchasing: boolean;
    error: string | null;
}

Key Actions:

• initializeRevenueCat(userId) - Called after auth, sets up SDK
• fetchOfferings() - Loads available packages for paywall
• purchasePackage(pkg) - Handles purchase with error handling
• restorePurchases() - Restores and syncs to server
• refreshSubscriptionStatus() - Checks RevenueCat and syncs to server

3. Webhook Handler (functions/revenuecat-webhook)

RevenueCat sends webhook events for subscription lifecycle changes.

Event Types Handled:

Event	Status Set
INITIAL_PURCHASE	active
RENEWAL	active
UNCANCELLATION	active
PRODUCT_CHANGE	active
CANCELLATION	cancelled
EXPIRATION	expired
BILLING_ISSUE	billing_issue
SUBSCRIPTION_PAUSED	paused

Idempotency: Events are logged to revenuecat_webhook_events table with unique event_id to prevent duplicate processing.

Flow:

1. Verify webhook secret (Authorization header)
2. Check for duplicate event_id
3. Record event in webhook_events table
4. Upsert subscription record
5. Database trigger syncs is_premium to profiles

4. Sync Function (functions/sync-subscription)

Called from client to verify subscription status server-side.

When Called:

• After purchase completes
• On app foreground (if status differs)
• Manual restore purchases

Flow:

1. Verify user JWT
2. Call RevenueCat API: GET /v1/subscribers/{user_id}
3. Check entitlement expiration date
4. Update profiles.is_premium

5. Database Layer

Tables:

-- Main subscription record
subscriptions (
    user_id UUID FK profiles,
    product_id TEXT,
    status subscription_status,  -- active/cancelled/expired/billing_issue/paused
    expires_at TIMESTAMPTZ,
    ...
)

-- Idempotency tracking
revenuecat_webhook_events (
    event_id TEXT UNIQUE,
    event_type TEXT,
    app_user_id TEXT,
    payload JSONB
)

Auto-Sync Trigger:

CREATE TRIGGER sync_premium_on_subscription_change
    AFTER INSERT OR UPDATE ON public.subscriptions
    FOR EACH ROW EXECUTE FUNCTION public.sync_premium_status();

This trigger updates profiles.is_premium based on active subscription status.

Premium Access Logic

Partner Premium Sharing

If either partner in a couple has premium, both get access:

CREATE FUNCTION public.has_premium_access(check_user_id UUID)
RETURNS BOOLEAN AS $$
    -- Returns TRUE if user OR their partner has is_premium = TRUE
$$;

RLS Policies

Premium packs are filtered at the database level:

CREATE POLICY "Users or partners with premium can view premium packs"
    ON public.question_packs FOR SELECT
    USING (
        is_premium = FALSE OR
        EXISTS (
            SELECT 1 FROM profiles p WHERE p.id = auth.uid()
            AND (p.is_premium = TRUE OR EXISTS (
                SELECT 1 FROM profiles partner
                WHERE partner.couple_id = p.couple_id
                AND partner.is_premium = TRUE
            ))
        )
    );

Question Filtering

The get_recommended_questions() function also filters premium packs:

-- Only include packs where:
(qp.is_premium = FALSE OR v_has_premium = TRUE)

Environment Variables

Variable	Location	Purpose
EXPO_PUBLIC_REVENUECAT_IOS_API_KEY	Mobile app	RevenueCat iOS public SDK key
EXPO_PUBLIC_REVENUECAT_ANDROID_API_KEY	Mobile app	RevenueCat Android public SDK key
EXPO_PUBLIC_REVENUECAT_ENTITLEMENT_ID	Mobile app	Entitlement identifier (code default: "pro"; builds set "Sauci Pro" — see warning below)
REVENUECAT_API_KEY	Edge functions	RevenueCat secret API key
REVENUECAT_ENTITLEMENT_ID	Edge functions	Server-side entitlement check
REVENUECAT_WEBHOOK_SECRET	Edge functions	Webhook auth verification

Entitlement ID mismatch risk. The fallback in src/lib/revenuecat.ts is "pro", but eas.json sets EXPO_PUBLIC_REVENUECAT_ENTITLEMENT_ID to "Sauci Pro". If that variable is missing from a build profile, the SDK looks up an entitlement that does not exist, parseCustomerInfo() returns isProUser: false, and paying users silently appear unsubscribed with no error. Confirm the variable is set on every iOS and Android build profile.

Subscription Flow Diagrams

Purchase Flow

User taps Subscribe
        │
        ▼
┌───────────────────┐
│ fetchOfferings()  │
└─────────┬─────────┘
          ▼
┌───────────────────┐
│ Display Paywall   │
└─────────┬─────────┘
          ▼
┌───────────────────┐
│ purchasePackage() │──▶ Native App Store UI
└─────────┬─────────┘
          ▼
┌───────────────────┐
│ RevenueCat SDK    │──▶ Sends webhook to server
│ returns success   │
└─────────┬─────────┘
          ▼
┌───────────────────┐
│ refreshStatus()   │──▶ Calls sync-subscription
└─────────┬─────────┘
          ▼
┌───────────────────┐
│ fetchUser()       │──▶ UI shows premium features
└───────────────────┘

Webhook Flow

RevenueCat Event (e.g., RENEWAL)
        │
        ▼
┌───────────────────────┐
│ revenuecat-webhook    │
│ Edge Function         │
└─────────┬─────────────┘
          │
          ├──▶ Check event_id (idempotency)
          │
          ├──▶ Record in webhook_events
          │
          ▼
┌───────────────────────┐
│ UPSERT subscriptions  │
└─────────┬─────────────┘
          │
          ▼
┌───────────────────────┐
│ sync_premium_status() │──▶ Updates profiles.is_premium
│ (Database Trigger)    │
└───────────────────────┘

Testing

RevenueCat sandbox mode is detected via event.environment !== "PRODUCTION" and stored in subscriptions.is_sandbox.

To test webhooks locally:

# Use ngrok or similar to expose local Supabase
supabase functions serve revenuecat-webhook --env-file .env.local