Make POST Creates Idempotent via Idempotency Keys

Make POST Creates Idempotent via Idempotency Keys | BeforeMerge Rules | BeforeMerge

Why this matters

Networks fail mid-request; clients retry. POST is not idempotent, so retries can double-charge or double-create. An idempotency key lets the server dedupe.

Bad

POST /charges   # retry creates a second charge

Good

POST /charges
Idempotency-Key: 9b2c...   # retry returns the original result

Why This Matters

Related Rules

Catch this automatically on every PR

Why this matters