KakaoTalk Chatbot Webhook Verification Fails: Fix FastAPI Endpoint for Kakao OpenBuilder
If you've set up a FastAPI server for your KakaoTalk chatbot and Kakao OpenBuilder keeps rejecting your webhook during the verification step, you're not alone. This is one of the most common stumbling blocks when building Kakao chatbots — the verification endpoint has a very specific response format, and even a small deviation causes it to fail silently. This post walks you through exactly what format Kakao expects, how to implement it correctly in FastAPI, and how to debug when things still go wrong. Table of Contents How Kakao Webhook Verification Works The Exact Response Format Kakao Expects FastAPI Implementation Common Mistakes and Fixes Testing Locally with ngrok Full Working Example Debugging Checklist 🔍 How Kakao Webhook Verification Works When you register a webhook URL in Kakao OpenBuilder, the platform sends a GET request to your endpoint to verify it's alive and responding correctly. This...