stripe-payments-demo

Stripe webhook idempotency and payment intent retry patterns, ported to Next.js 16 App Router for Vercel deploy.

Endpoints

• POST /api/webhook — Stripe webhook receiver. Verifies Stripe-Signature via HMAC-SHA256, then Redis SETNX guard with a 24h TTL on stripe:event:{id}.
• POST /api/create-payment-intent — Caller-supplied idempotencyKey. Exponential-backoff retry on 5xx / network errors; no retry on 4xx card declines.
• POST /api/simulate-payment — Demo helper; server generates the idempotencyKey.
• GET /api/health — liveness probe.

Sequence

Stripe -> POST /api/webhook
  verify Stripe-Signature (HMAC-SHA256)
    invalid -> 400
    valid   -> SETNX stripe:event:{id} EX 86400
                duplicate -> 200 { duplicate: true }
                new       -> dispatch by event.type -> 200

Source: github.com/Shailesh93602/stripe-payments-demo