The Hidden Trap in Backend Tutorials: Why Your Webhooks Are Creating Duplicate Data (And How to Fix It)

We've all been there. You're sitting at your desk late at night, watching a backend tutorial, fueled by coffee and determination. The instructor shows you how to integrate a payment gateway or a webhook, and it looks incredibly simple:

Receive the webhook event.

Update the database.

Return a 200 OK.

You write the code, test it locally, and it works perfectly. You push it to production feeling like a senior engineer.