parallel45 API error

idempotency_key_reused

Idempotency key reused with a different request

Published ahead of the API. No endpoint emits this code yet — error exits currently carry type: "about:blank". Read this as the intended contract, not as a description of live behaviour. About this catalogue

Problem type
https://errors.parallel45.tech/idempotency_key_reused
HTTP status
409
Retryable
No — the identical request will fail identically.

What it means

This Idempotency-Key was already used, with a different request body.

A key identifies one intent. The same key arriving with a changed fingerprint means the caller derived it wrongly, or is about to act twice under a stale one. It is refused rather than executed, and this is a defect in the caller rather than a transient fault.

What to do

Fix the key derivation: mint one key per intent and reuse it unchanged across every retry of that intent. Do not retry this request as-is, and do not mint a fresh key to get past it -- that is how a duplicate is created.

Do not confuse this with

idempotency_request_in_progress. Same status, opposite retryability: that one is a race worth retrying, this one never succeeds.