FTB-C000706 / Implementation concept

Idempotency key

An idempotency key lets an application recognize retries of one logical request within a declared scope.

Also known asidempotency keys

Intermediate 6 linked topicsEvidence-reviewed

Definitions

In plain terms

After a lost response, a client can repeat the same identified request instead of accidentally creating a second operation.

Technical

D30 binds an accepted scoped identity to its payload and result; a changed accepted payload conflicts, while definite rejection reserves no identity.

Scope

Retention, rejected requests and concurrent execution policies are API-specific.

Examples

  • A lost posting response is retried with the original key and payload to recover the retained result.

Common misconceptions

  • Reusing a key does not provide global exactly-once behavior outside its scope.

Concept relationships

Related

Where this concept is used

Evidence and governance

  1. Idempotent requests Stripe · official platform documentation

    Supports: preferred label, short definition, variant distinction

    Limits: Stripe v1/v2 differ and retention/execution rules are platform-specific; the D30 model is not a Stripe implementation.

  2. D30 glossary teaching-profile scope, Batch 013 The Fintech Builder · internal governed contract

    Supports: technical definition

    Limits: No independent regulatory mandate, real-bank dataset, service execution, external witness or production assurance is claimed.

Reviewed by
fintech-builder-batch-013
Last reviewed
2026-10-27
Next review
2027-10-27
Record status
evidence reviewed

This record is evidence-reviewed and readable, but not yet promoted to published — it is served noindex,follow and excluded from the sitemap.

Written by

Fintech engineer building market-data and financial systems, and the author of every article, glossary record, and reference implementation on The Fintech Builder.