OpenAI + Stripe + Supabase in a React Native boilerplate

The stack

• React Native 0.83.6 + Expo SDK 55.0.17
• OpenAI: REST client at src/features/gen-ui/api/openai.api.ts
• Stripe: server-side via a Supabase Edge Function (Deno runtime). No mobile SDK needed for web checkout
• Supabase: Auth + Postgres + RLS + Edge Functions for the Stripe webhook handler
• WebView for Stripe Checkout: react-native-webview

Setup in five steps

1. Strip out RevenueCat from Standard

# Delete:
# - src/features/paywall/services/revenuecat.service.ts
# - src/features/paywall/components/PaywallScreen.tsx (replace)
# Remove react-native-purchases from package.json

2. Stripe Edge Function

// supabase/functions/create-checkout/index.ts
// Stripe-Node works in Deno via npm: imports
import Stripe from "npm:stripe";
const stripe = new Stripe(Deno.env.get("STRIPE_SECRET_KEY")!);
// POST { priceId, userId } -> { url }
// stripe.checkout.sessions.create({ ..., success_url: "myapp://billing/success" })

3. Env

# .env (server-only, Supabase Edge Function secret)
STRIPE_SECRET_KEY=sk_live_...
STRIPE_WEBHOOK_SECRET=whsec_...

# .env (client)
EXPO_PUBLIC_SUPABASE_URL=https://<project>.supabase.co
EXPO_PUBLIC_SUPABASE_ANON_KEY=<anon-key>
OPENAI_API_KEY=sk-...  # server-side proxy only

4. Webhook -> entitlements

-- Supabase
create table entitlements (
  user_id uuid references auth.users primary key,
  tier text not null,
  current_period_end timestamptz not null
);
-- Stripe webhook upserts on customer.subscription.updated

5. App Store review

Read Apple guideline 3.1.3 before submitting. Most B2B / reader categories (file storage, business productivity, enterprise SaaS) can use external payments. Most consumer categories cannot. Plan the review strategy before writing code.

Why this combo works

Stripe gives you 2.9% + 30c instead of Apple's 15-30%. On a $20/mo plan that is the difference between $19.13 net and $14 net. For B2B with a tiny mobile companion, the math is obvious.

The mobile-only catch: Apple does not let you mention Stripe in-app for consumer categories. You can have a Stripe-paid subscription, you just cannot tell users about it inside iOS without a Reader app exemption. For most B2C AI apps, RevenueCat is the right answer despite the higher fees.

Supabase Edge Functions are the right place for the Stripe handlers because they run in Deno and accept the Stripe SDK as an npm import. No separate Node server, no extra deploy target.

What it costs at scale

Compared to RevenueCat + Apple at $10K MRR: $200 + $1500-3000 store fee. Stripe saves money only if your audience pays outside the iOS/Android stores.

What this combo does NOT cover

• In-app purchases for consumer iOS apps: Apple guideline 3.1.1 forbids it for most categories
• Receipt restoration UX on device-swap: RevenueCat does this for free; Stripe needs custom code
• Out-of-the-box wiring: you graft this in over a weekend
• Family Sharing / Ask to Buy: Apple-only features