Designing Reliable Webhook Processing Systems
January 15, 2025
Webhooks are the glue between Stripe, CRMs, internal tools, and your database. When they're designed poorly, events get lost, duplicates get processed twice, and nobody knows why a sync failed at 2am.
Here's how to design webhook processing that stays reliable as volume grows.
1. Idempotency is non-negotiable
Providers often retry. If you process the same event twice, you double-charge, double-create, or corrupt state. Store a key (e.g. provider event ID) and short-circuit if you've already handled it. Do this before any side effects.
2. Acknowledge fast, process async
Return 200 quickly. Put the payload in a queue (Pub/Sub, Cloud Tasks, or a durable queue) and process in a worker. That way the provider doesn't time out and retry while you're still working.
3. Retries with backoff and dead-letter
Transient failures happen. Retry with exponential backoff and a max attempt count. After that, send to a dead-letter queue or log for manual inspection. Don't let bad events block the queue.
4. Observability from day one
Log every received event, processing start, and outcome (success/failure). With correlation IDs you can trace a single webhook end-to-end. Alerts on failure rate or queue depth prevent surprises.
5. Security: verify signatures and validate payloads
Always verify the webhook signature (e.g. Stripe, SendGrid). Validate payload shape and reject invalid or unexpected events before they touch your data.
Reliable webhook processing is the foundation of automation and workflow engineering. If your current pipelines are fragile, request an architecture review to harden them.