Validation rules

BR-31 — EN 16931 rule

A document-level allowance (BG-20) has no allowance amount (BT-92).

Rule: BR-31 — official EN 16931 / XRechnung rule
Severity: error
Business term: BT-92 — Document allowance amount
Field in your JSON: invoice.allowances[*].amount
Detected by: tier 3 — KoSIT validator (authoritative)
Reachability: Only reachable when validating your own XML — normbill-generated documents cannot trigger it

The request schema requires amount (or base_amount + percent) on every allowance and the serializer always writes cbc:Amount; the UBL schema makes the element mandatory too, so the XSD tier reports hand-built XML without it first.

How to fix it

Add cbc:Amount to the allowance.

BR-31 auf Deutsch — was bedeutet der Fehler?

Ein Nachlass auf Dokumentebene (BG-20) hat keinen Nachlassbetrag (BT-92).

So beheben Sie den Fehler

Ergänzen Sie cbc:Amount im Nachlass.

Related rules

BR-DEC-01 — A document-level allowance amount (BT-92) has more than 2 decimal places.
BR-32 — A document-level allowance needs a VAT category (BT-95); it cannot be inherited because the lines use more…
BR-30 — An invoice line period end date (BT-135) must not be earlier than its start date (BT-134).
BR-33 — A document-level allowance must state why it is granted (BT-97/BT-98).
BR-29 — The invoicing period end date (BT-74) must not be earlier than its start date (BT-73).
BR-28 — The item gross price (BT-148) must not be negative.

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.