Problem types of the Partner API

The Partner API reports errors in the application/problem+json format (RFC 9457). The type field contains the address of one of the following pages and is a stable identifier of the kind of error. Match on type (or the HTTP status) in your code, not on the text in title or detail, which may change.

Problem type	Status	Meaning
Bad request	400	The request could not be read because the body is not valid JSON or the wrong Content-Type was sent.
Unauthorized	401	The API key is missing, invalid or revoked.
Forbidden	403	The API key is valid, but the merchant has no active API subscription.
Not found	404	The requested order or webhook does not exist or belongs to another merchant.
Order already exists	409	An order with this external_order_id (or Idempotency-Key) already exists, but the body you sent differs from the original.
Order not cancellable	409	The order can no longer be cancelled through the API because the merchant has already accepted it.
Validation error	422	The request is valid JSON, but its content is not acceptable.
Rate limited	429	The rate limit of your API key was exceeded (60 requests per minute during the beta).
Internal error	500	A temporary problem occurred on our side.