Validation rules
BR-O-11 — EN 16931 rule
VAT category "O" (not subject to VAT) cannot be mixed with other VAT categories on the same invoice (BR-O-11..14).
- Rule
BR-O-11— official EN 16931 / XRechnung rule- Severity
- error
- Business term
BT-151— Line VAT category- Field in your JSON
invoice.lines[*].vat_category
How to fix it
Move the O lines to a separate invoice, or correct their vat_category.
BR-O-11 auf Deutsch — was bedeutet der Fehler?
Die Kategorie "O" (nicht umsatzsteuerbar) darf nicht mit anderen Umsatzsteuer-Kategorien auf derselben Rechnung gemischt werden (BR-O-11 bis BR-O-14).
So beheben Sie den Fehler
Stellen Sie die O-Positionen auf eine separate Rechnung — oder korrigieren Sie deren vat_category.
Related rules
BR-CO-04— An invoice line is not categorized with a VAT category code (BT-151).BR-AE-01— Lines or document-level allowances/charges use VAT category "AE" (reverse charge), so the VAT breakdown…BR-B-01— VAT category "B" (Italian split payment) is only allowed on domestic Italian invoices — every country code…BR-B-02— VAT category "B" (Italian split payment) must not be combined with category "S" (standard rated) on the same…BR-E-01— Lines or document-level allowances/charges use VAT category "E" (exempt), so the VAT breakdown (BG-23) must…BR-G-01— Lines or document-level allowances/charges use VAT category "G" (export outside the EU), so the VAT…
Official sources
- XRechnung specification (KoSIT / xeinkauf.de)
- KoSIT validator on GitHub and the XRechnung validator configuration
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.