FIX

Postmortems

A real failure, the experiments that isolated it, the root cause and the fix

A real failure, the experiments that isolated it, the root cause and the fix

3 articles

All articles Hands-on Labs Reality Check Postmortems Building Explainers Commentary
Tech Deep Dive

The Mysterious 400 in Claude Multi-Turn Chats: Debugging a Thinking Signature Corruption

A customer's Claude extended-thinking conversations kept failing with 400 Invalid signature — but only on some gateway channels. A full postmortem: what the signature mechanism is, how a proxy's JSON re-serialization silently corrupts base64, five controlled experiments that pinned it down, and a fix checklist for every LLM gateway developer.
Cloud Architecture

5 Pitfalls of Logging Failed Requests with CloudFront + Lambda@Edge

We built a dual Lambda@Edge setup for full request logging on CloudFront. Here are the 5 things that went wrong.
Tech Deep Dive

Adding a Unique Index to a 15-Million-Row MySQL Table: A Production War Story

We added a unique index to a 15M-row live table and caused an outage. Here's what went wrong and the right way to do it.