Feature

Idempotency

Safe retries without duplicate side effects.

21 providers 137 APIs 14 declared variants

Idempotency keys or exactly-once semantics let clients retry after a timeout without double-charging or double-writing. Essential wherever operations move money or state.

21 API providers on the APIs.io network offer idempotency. The highest-rated are Stripe, Novu, Knock, Flutterwave, Raygun.

Providers

Ranked by API Evangelist rating — Exemplar and Strong are expanded by default.

Exemplar 3 Complete, well-documented, and agent-ready
Strong 6 Solid coverage with minor gaps
Developing 6 Usable, with meaningful gaps to close
Thin 5 Limited public surface area
Emerging 1 Early or largely undocumented

What Providers Actually Declared

This feature is a canonical term. These are the free-text strings providers wrote in their own apis.yml that map onto it.

ACID TransactionsACID transactions across regionsCrash Reporting — error detection, deduplication into error groups, full stack-trace and breadcrumb contextDeductions endpoints (list types, list, create, update, cancel) with per-row operation_id idempotencyExactly-Once SemanticsHTTPS-only webhook endpoints with retry on non-2xx; idempotency keyed on `(workflowId, status, timestamp)`Idempotency + RateLimit HeadersIdempotency keys on POST/PATCH via UUID v4 with 24-hour response cacheIdempotency via `X-Idempotency-Key` (UUID) returned on retry with `X-Idempotency-Cache-HitIdempotency-Key header support for safe automatic retriesIdempotency-Key support for safe retriesIdempotent requests via Idempotency-KeyMulti-document ACID transactionsNo idempotency mechanism anywhere in the surface — writes are not replay-safe

Scroll for all 14

Work with this as data

Every feature here is available over the APIs.io API and to AI agents over MCP. Features is not yet its own endpoint on the v1 API. Reach it through catalog search and the tag graph, or the MCP server.

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Tools for features

3 MCP tools reach this
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
Search the catalog
curl "https://apis.io/api/v1/search?q=idempotency&limit=10"
Everything under a tag
curl "https://apis.io/api/v1/tags/idempotency"

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