Validation rules

BR-O-05 — EN 16931 rule

A line "not subject to VAT" (O) must not carry a VAT rate.

Rule: BR-O-05 — official EN 16931 / XRechnung rule
Severity: error
Business term: BT-152 — Line VAT rate
Field in your JSON: invoice.lines[*].vat

How to fix it

Remove line.vat (or set it to 0) on category O lines.

BR-O-05 auf Deutsch — was bedeutet der Fehler?

Eine Position der Kategorie "O" (nicht umsatzsteuerbar) darf keinen Steuersatz tragen.

So beheben Sie den Fehler

Entfernen Sie line.vat auf Positionen mit Kategorie O.

Related rules

BR-S-05 — A standard-rated (S) line must have a VAT rate greater than zero.
BR-Z-05 — A zero-rated (Z) line must have a VAT rate of exactly 0.
BR-E-05 — A VAT-exempt (E) line must have a VAT rate of 0.
BR-AE-05 — A reverse-charge (AE) line must have a VAT rate of 0.
NB-VAT-RATE — A line has neither a VAT rate nor a VAT category — the category cannot be determined.
BR-IC-05 — An intra-community supply (K) line must have a VAT rate of exactly 0.

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.