Yumin Fish Harvest

Sep 21, 2026 · Backend Development

Idempotency Design for Write Services: 7 Patterns & Selection Guide

This article details seven idempotency patterns for backend write operations—including unique keys with database constraints, state machines, execution records, naturally idempotent actions, request fingerprinting, client-generated keys, and server-issued tokens—with concrete examples, SQL code, and a selection guide to match each pattern to specific business scenarios like payment callbacks, order cancellations, and duplicate purchases.