Validation rules

BR-50 — EN 16931 rule

A credit-transfer payment account is present but its account identifier (IBAN, BT-84) is empty.

Rule: BR-50 — official EN 16931 / XRechnung rule
Severity: error
Business term: BT-84 — Payment account IBAN
Field in your JSON: invoice.payment.iban
Detected by: tier 3 — KoSIT validator (authoritative)
Reachability: Only reachable when validating your own XML — normbill-generated documents cannot trigger it

The serializer only writes the account group when invoice.payment.iban is set (min. 15 characters), so generated documents never carry an empty BT-84.

How to fix it

Put the IBAN (or other account identifier) into cac:PayeeFinancialAccount/cbc:ID.

BR-50 auf Deutsch — was bedeutet der Fehler?

Ein Überweisungskonto ist angegeben, aber die Kontokennung (IBAN, BT-84) ist leer.

So beheben Sie den Fehler

Tragen Sie die IBAN (oder andere Kontokennung) in cac:PayeeFinancialAccount/cbc:ID ein.

Related rules

BR-DE-23-a — Payment means is a credit transfer (code 30/58) but no payment account (IBAN, BT-84) is given.
BR-DE-25-b — Payment means is a SEPA direct debit (code 59), so a payee account (BG-17) must not be present. normbill…
NB-IBAN-CHECKSUM — The IBAN fails its checksum — this is almost certainly a typo.
BR-61 — The payment means is a credit transfer (code 30 or 58), so a payment account identifier (IBAN, BT-84) is…
BR-DE-19 — The payment account identifier (BT-84) does not look like a valid IBAN — for SEPA credit transfers (means…
BR-49 — Payment instructions (BG-16) are present but the payment means type code (BT-81) is missing.

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.