Building a Robust Webhook Handler in Node.js: Validation, Queuing, and Retry Logic

Webhooks are everywhere. Stripe fires one when a payment succeeds. GitHub fires one when a PR is merged. Twilio fires one when an SMS lands. And when your handler is flaky — when it misses events, fails silently, or chokes under load — you lose data and trust. Most tutorials show you how to receive a webhook. Few show you how to handle it properly. This article covers the full picture: signature validation, idempotency, async queuing, and retry logic with exponential backoff. We'll use Node.js and Express throughout, with no external queue infrastructure required. One important caveat up front: the queuing approach in this article is designed for a single, long-lived Node.js process. If you're running on serverless functions (Lambda, Cloud Run) or horizontally scaled deployments with multiple instances, in-memory queues are not reliable — skip ahead to the When to Upgrade section for the right tool in those cases. TL;DR Summary Concern Solution Fake webhook senders HMAC-SHA256 signatur