Validation rules

BR-64 — EN 16931 rule

An item standard identifier (BT-157) has no scheme identifier.

Rule: BR-64 — official EN 16931 / XRechnung rule
Severity: error
Business term: BT-157 — Item standard identifier
Field in your JSON: invoice.lines[*].standard_item_id.id
Detected by: tier 3 — KoSIT validator (authoritative)
Reachability: Not expressible through the normbill invoice model — documented for completeness

The request schema requires standard_item_id.scheme whenever standard_item_id is set; the serializer always writes schemeID.

How to fix it

Set the schemeID attribute on cac:StandardItemIdentification/cbc:ID (e.g. 0160 for GTIN).

BR-64 auf Deutsch — was bedeutet der Fehler?

Einer Artikel-Standardkennung (BT-157) fehlt die Schema-Kennung.

So beheben Sie den Fehler

Setzen Sie das schemeID-Attribut auf cac:StandardItemIdentification/cbc:ID (z. B. 0160 für GTIN). Über normbill ist standard_item_id.scheme Pflicht.

Related rules

BR-63 — The buyer electronic address (BT-49) has no scheme identifier.
BR-65 — An item classification code (BT-158) has no scheme identifier.
BR-62 — The seller electronic address (BT-34) has no scheme identifier.
BR-61 — The payment means is a credit transfer (code 30 or 58), so a payment account identifier (IBAN, BT-84) is…
BR-57 — A deliver-to address (BG-15) must contain a country code (BT-80).
BR-56 — A seller tax representative (BG-11) must carry the representative's VAT identifier (BT-63).

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.