Validation rules

BR-51

A card payment must never carry the full primary account number (BT-87) — at most the first 6 and last 4 digits are allowed.

Rule: BR-51 — official EN 16931 / XRechnung rule
Severity: error
Business term: BT-87
Detected by: tier 3 — KoSIT validator (authoritative)
Reachability: Not expressible through the normbill invoice model — documented for completeness

The normbill invoice model has no card payment information (BG-18).

How to fix it

Truncate the card number in cac:CardAccount/cbc:PrimaryAccountNumberID.

BR-51 auf Deutsch — was bedeutet der Fehler?

Bei Kartenzahlung darf niemals die vollständige Kartennummer (BT-87) übertragen werden — höchstens die ersten 6 und letzten 4 Ziffern.

So beheben Sie den Fehler

Kürzen Sie die Kartennummer in cac:CardAccount/cbc:PrimaryAccountNumberID.

Official sources

Every 422 from the API lists the rule id, the path in your request JSON, a plain-language message and a suggested fix — see the docs overview for the report format.

Or try it live: drop any XRechnung XML on the free validator — same KoSIT-backed report, no account.