Beyond the Naive Fix: Engineering Reliable Idempotency in Go

Idempotency-key handling is critical in payment systems where retries can cause duplicate charges, yet naive implementations often fail under real-world concurrency. This article reveals why basic solutions like Redis SETNX break under load and presents a robust Go middleware implementing Stripe-compatible idempotency with atomic guarantees. Understanding these patterns is essential for any backend engineer building order processing or payment APIs.