Stripe Payment Processing Setup Checkout Session (simplest integration) Payment Intents (custom UI) Subscriptions Webhooks (critical) Critical: Use — parsed body breaks signature verification. Anti-Patterns | Anti-Pattern | Fix | |--------------|-----| | Trust client-side amount | Calculate amount server-side only | | No webhook handling | Always use webhooks for fulfillment | | Storing card numbers | Use Stripe.js — never touch card data | | No idempotency keys | Add to all create operations | | Fulfilling before payment confirms | Wait for webhook confirmation | | No error handling on clien…