Validation rules

BR-CO-23 — EN 16931 rule

An invoice line allowance (BG-27) carries neither a reason text (BT-139) nor a reason code (BT-140) — at least one is required.

Rule: BR-CO-23 — official EN 16931 / XRechnung rule
Severity: error
Business term: BT-139 — Line allowance reason
Field in your JSON: invoice.lines[*].allowances
Detected by: tier 1 — normbill pre-flight (also in the playground)
Reachability: Triggerable from your request JSON (generate & validate)

normbill's pre-flight reports the equivalent finding as BR-42 at tier 1.

How to fix it

Set the line allowance's reason or a UNCL 5189 reason_code.

BR-CO-23 auf Deutsch — was bedeutet der Fehler?

Ein Positionsnachlass (BG-27) trägt weder einen Grundtext (BT-139) noch einen Grundcode (BT-140) — mindestens eines ist Pflicht.

So beheben Sie den Fehler

Setzen Sie reason des Positionsnachlasses oder einen UNCL-5189-reason_code. normbill meldet denselben Befund bereits vorab als BR-42.

Related rules

BR-42 — A line-level allowance must state why it is granted (BT-139/BT-140).
BR-CO-22 — A document-level charge (BG-21) carries neither a reason text (BT-104) nor a reason code (BT-105) — at least…
BR-CO-24 — An invoice line charge (BG-28) carries neither a reason text (BT-144) nor a reason code (BT-145) — at least…
BR-CO-25 — An amount is due but neither a due date (BT-9) nor payment terms (BT-20) are present.
BR-CO-21 — A document-level allowance (BG-20) carries neither a reason text (BT-97) nor a reason code (BT-98) — at…
BR-CO-26 — The seller carries none of: VAT identifier (BT-31), legal registration identifier (BT-30) or seller…

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.