Error Handling

Every error response has one shape:

{"error": "ValidationError", "message": "iban: must be a valid IBAN"}

Status	error	When
400	ValidationError	A field is missing or malformed
400	InvalidIban	The IBAN does not validate or its bank is not supported
401	Unauthorized	Missing, expired or invalid Bearer token
403	InsufficientScope	The token lacks the openbanking.api scope
403	MissingClientBinding	The OAuth client is not yet bound to a Magni client (provisioning pending)
404	NotFound	The account does not exist or belongs to another client
429	RateLimited	See Rate limiting; honour Retry-After
502	UpstreamError	The bank or the SIBS gateway failed; retry later

Treat error as the stable key and message as human-readable text that may change.