validation_failed

What it means

One or more fields are invalid. errors[] lists each problem with a JSON pointer, a field-level code (for example must_be_past, invalid_uk_postcode, not_excludable, primary_required, step_not_enabled) and a message. A JSON body sent without Content-Type: application/json is also refused with this code (§5).

What to do

Do not retry unchanged. Show errors[] to the user, fix the data and resend (§12.4).

Example response

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

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

{
  "type": "https://www.underwritinguk.ai/developers/errors/validation_failed",
  "title": "Request validation failed",
  "status": 422,
  "code": "validation_failed",
  "detail": "Request validation failed.",
  "request_id": "7b0b1e5c-2f7e-4a52-9a43-5b0d0f0e9d11"
}

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