Day 13: Build your secure backend trigger
ยท 37 min read

What you'll learn
How to build a secure Lambda backend with API Gateway and Cognito authorization to trigger AI calls
Why you need a secure triggerโ
Day 12: You build a protected frontend
Today: We build the secure backend that triggers calls
Here's the critical security issue:
Remember your ALB endpoint we built on Day 9 โ?
https://ai-caller.yourdomain.com
If we add a /make-call endpoint directly to Fargate:
POST https://ai-caller.yourdomain.com/make-call
โ Publicly accessible
โ Anyone can trigger calls
โ Could rack up *huge* OpenAI/Twilio bills
โ Even with frontend auth, the endpoint is exposed
This is not acceptable.
