Glossary
What is Idempotent Webhooks?
Webhook handlers that produce the same result whether they receive an event once or multiple times. If Stripe sends the same payment webhook twice (which happens), an idempotent handler processes it once and ignores the duplicate. Non-idempotent handlers create duplicate charges, duplicate subscriptions, or duplicate records.
Last updated: May 2026
Why it matters
Payment providers guarantee at-least-once delivery, not exactly-once. Webhooks will be sent multiple times during network issues, retries, or provider-side incidents. Without idempotency, you'll overcharge customers, create duplicate records, and spend hours reconciling your database with your payment provider.
Where AI gets this wrong
How AI tools get this wrong, and why it matters for your app.
AI generates Stripe webhook handlers that process events and return 200. They don't implement idempotency keys, duplicate detection, or dead-letter queues. The webhook works. Until Stripe retries a payment event and you double-charge someone.
Stuck on idempotent webhooks?
I handle the production engineering that AI can't. Book a free intro call and get your app past the 80% wall.