Validation rules

BR-O-13 — EN 16931 rule

An invoice with a "not subject to VAT" (O) breakdown must not contain document-level allowances with any other VAT category.

Rule: BR-O-13 — official EN 16931 / XRechnung rule
Severity: error
Detected by: tier 3 — KoSIT validator (authoritative)
Reachability: Triggerable from your request JSON (generate & validate)

How to fix it

Set the allowance's vat_category to "O" (and omit its vat), or move the O items to a separate invoice.

BR-O-13 auf Deutsch — was bedeutet der Fehler?

Eine Rechnung mit einer O-Aufschlüsselung ("nicht umsatzsteuerbar") darf keine Nachlässe auf Dokumentebene mit einer anderen Umsatzsteuer-Kategorie enthalten.

So beheben Sie den Fehler

Setzen Sie die vat_category des Nachlasses auf "O" (und lassen Sie vat weg) — oder stellen Sie die O-Posten auf eine separate Rechnung.

Related rules

BR-O-12 — An invoice with a "not subject to VAT" (O) breakdown must not contain lines with any other VAT category…
BR-O-14 — An invoice with a "not subject to VAT" (O) breakdown must not contain document-level charges with any other…
BR-O-11 — VAT category "O" (not subject to VAT) cannot be mixed with other VAT categories on the same invoice…
BR-O-10 — Lines use VAT category "O" (not subject to VAT) but no exemption reason (BT-120) or reason code (BT-121) is…
BR-O-09 — The tax amount (BT-117) of the "not subject to VAT" (O) breakdown must be 0.
BR-O-08 — The taxable amount (BT-116) of the "not subject to VAT" (O) breakdown does not equal the sum of line net…

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.