API error · HTTP 400

`idempotency_key_required`

Idempotency-Key header required

HTTP status	400 Bad Request
`code`	`idempotency_key_required`
`title`	Idempotency-Key header required
Retry?	No

What it means

Every POST that creates something needs an Idempotency-Key header, and this one had none.

What to do

Send Idempotency-Key: <uuid-v4>. Generate one key per logical operation and reuse that key on every retry of the same operation (§5).

Example response

Branch on code, never on title or detail. detail varies; quote request_id to support.

HTTP

HTTP/1.1 400 Bad Request
Content-Type: application/problem+json

{
  "type": "https://www.underwritinguk.ai/developers/errors/idempotency_key_required",
  "title": "Idempotency-Key header required",
  "status": 400,
  "code": "idempotency_key_required",
  "detail": "Idempotency-Key header required.",
  "request_id": "7b0b1e5c-2f7e-4a52-9a43-5b0d0f0e9d11"
}

All error codes · Error catalogue in the integration guide (§15) · Error handling and retries (§12.4)