Validation rules

BR-CL-18

A line VAT category code (BT-151) is not one of the UNCL 5305 values EN 16931 permits (AE, L, M, E, S, Z, G, O, K, B).

Rule: BR-CL-18 — 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

line.vat_category is an enum in the request schema (default S when a rate is given), so generated documents always carry a permitted code — only XML submitted directly to /v1/invoices/validate can violate this.

How to fix it

Use one of the permitted codes in cac:ClassifiedTaxCategory/cbc:ID — in the request JSON, line.vat_category only accepts them.

BR-CL-18 auf Deutsch — was bedeutet der Fehler?

Die Umsatzsteuer-Kategorie einer Position (BT-151) ist keiner der in EN 16931 zulässigen UNCL-5305-Codes (AE, L, M, E, S, Z, G, O, K, B). Generierte Dokumente sind durch das Eingabeschema geschützt (line.vat_category ist ein Enum) — betroffen ist nur eigenes XML an /v1/invoices/validate.

So beheben Sie den Fehler

Verwenden Sie in cac:ClassifiedTaxCategory/cbc:ID einen der zulässigen Codes.

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.