Mastering Webhook Signature Verification in Local Dev

Short summary

Webhook signature verification fails in local development due to body parsing, wrong secrets, or clock skew. This guide covers common failure patterns and fixes with code examples, then introduces Anonymily—a tool for offline webhook capture, replay, and AI editor integration via MCP. For production scale, consider Hookdeck or Svix.

• •Body parsing middleware strips the raw buffer needed for HMAC verification; capture it with the verify callback in express.json()
• •Clock skew and wrong webhook secrets are frequent failure points; always use the correct local/test secret from your provider
• •Anonymily provides stable endpoints, offline capture, one-click replay, and MCP integration for debugging with AI editors

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