Validation rules

UBL-SR-48

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.

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.