Validation rules

BR-06

The seller name (BT-27) is missing or empty.

Rule

BR-06 — official EN 16931 / XRechnung rule

Severity

error

Business term

BT-27 — Seller name

Field in your JSON

invoice.seller.name

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 invoice.seller.name, so generated documents always carry BT-27.

How to fix it

Provide cac:PartyLegalEntity/cbc:RegistrationName on the supplier party.

Official sources

• XRechnung specification (KoSIT / xeinkauf.de)
• KoSIT validator on GitHub and the XRechnung validator configuration

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.