#api-design

Web Development Bug Report

A mobile client sent a partial PUT and our API wiped every field it left out

Amara Nwosu · Nov 10, 2026 · 8 min read

After a mobile release, customers who changed their delivery phone number lost their saved address notes and opening hours. The app was sending a partial body with PUT, and the API did exactly what PUT means. The fix: PATCH with JSON Merge Patch, and a PUT that rejects partial bodies.

Web Development Bug Report

Same idempotency key, different payment amount: our API returned the old charge as success

Amara Nwosu · Nov 2, 2026 · 8 min read

A partner reused one idempotency key for two different charges. Our API matched the key, replayed the first response and reported success for a payment that never happened. We now store a fingerprint of the request, reject mismatches with 422 and scope keys properly.

Engineering Practice

Ten small backend habits that turn into slow systems and incidents

John Nguyen · Feb 2, 2025 · 7 min read

Most of our worst backend incidents did not start with a big design flaw. They started with a swallowed exception, a missing index or an endpoint that returned everything. Here are ten habits we now block in code review, and what we do instead.