The 400 Bad Request Ghost
You’ve set up your listener, configured your tunnel, and triggered a test event from Stripe or GitHub. Everything looks perfect, but your console logs a cryptic error: Invalid signature or a blunt 400 Bad Request.
webhook signature verification is the primary security mechanism that ensures a request actually came from the provider and wasn't intercepted or forged. While the concept is simple—hash the payload with a shared secret and compare it to a header—the implementation is where most developers lose hours of productivity.
In this guide, we’ll look at why signature verification fails, how to fix it in your code, and how to improve your local development workflow using tools like Anonymily to stop the "trigger-fail-restart" cycle.
The Core Concept of Webhook Signature Verification
