Validation rules
UBL-SR-48 — UBL rule
An invoice line does not have exactly one cac:ClassifiedTaxCategory — every line states its VAT category (BT-151) exactly once.
- Rule
UBL-SR-48— official EN 16931 / XRechnung rule- Severity
- error
- Business term
BT-151— Line VAT category- Field in your JSON
invoice.lines[*].vat_category- Detected by
- tier 3 — KoSIT validator (authoritative)
- Reachability
- Only reachable when validating your own XML — normbill-generated documents cannot trigger it
The serializer always emits exactly one ClassifiedTaxCategory per line.
How to fix it
Keep exactly one ClassifiedTaxCategory inside cac:Item per line. Through normbill, set line.vat or line.vat_category.
UBL-SR-48 auf Deutsch — was bedeutet der Fehler?
Der KoSIT-Validator lehnt die Rechnung ab, weil eine Position nicht genau eine cac:ClassifiedTaxCategory trägt — jede Position nennt ihre Umsatzsteuer-Kategorie (BT-151) genau einmal.
So beheben Sie den Fehler
Behalten Sie genau eine ClassifiedTaxCategory in cac:Item je Position. Über normbill setzen Sie line.vat oder line.vat_category.
Related rules
BR-O-11— VAT category "O" (not subject to VAT) cannot be mixed with other VAT categories on the same invoice…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…
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.