422 Idempotency key reused

An Idempotency-Key you already used on this endpoint was sent again with a different request body, so the request cannot be a replay of the first.

Retry only after changing the request

What causes it

• A key generator that repeats (a counter that reset, a fixed string per workflow) rather than one key per logical request.
• A retry that changed the payload, for example a mapped field that resolved to a new value.

How to fix it

• Send a new key for a new request. Reuse a key only to replay the identical body; a replay returns the resource the first call created.

Example response

HTTP/1.1 422
Content-Type: application/problem+json

{
  "type": "https://sealdeal.ai/errors/idempotency-key-reused",
  "title": "Idempotency key reused",
  "status": 422,
  "detail": "..."
}

`type` is stable and safe to branch on in code. `detail` is specific to your request and is the field to read for the particulars; its wording may change.