Validation rules

UBL-SR-31

A document-level charge carries more than one reason text (BT-104) — only one cbc:AllowanceChargeReason per charge is allowed.

Rule: UBL-SR-31 — official EN 16931 / XRechnung rule
Severity: error
Detected by: tier 3 — KoSIT validator (authoritative)
Reachability: Only reachable when validating your own XML — normbill-generated documents cannot trigger it

The serializer emits at most one reason per charge, from invoice.charges[i].reason.

How to fix it

Keep a single AllowanceChargeReason per cac:AllowanceCharge. Through normbill, each charge has one reason string.

UBL-SR-31 auf Deutsch — was bedeutet der Fehler?

Der KoSIT-Validator lehnt die Rechnung ab, weil ein Zuschlag auf Dokumentebene mehrere Begründungstexte (BT-104) trägt — nur eine cbc:AllowanceChargeReason je Zuschlag ist erlaubt.

So beheben Sie den Fehler

Behalten Sie genau eine AllowanceChargeReason je cac:AllowanceCharge. Über normbill hat jeder Zuschlag einen reason-String.

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.