BR-02
The invoice must have an invoice number (BT-1).
- Severity
- Error
- Applies to
- CII, UBL
- Rule set
- v2026-01-31
Official rule text
An Invoice shall have an Invoice number (BT-1).
Why it happens
In practice almost always a mapping error: the field is named differently internally and never populated on export, or the number is assigned only after the document is generated.
How to fix it
Populate BT-1 with your invoice number before generating the document — cbc:ID at document level in UBL, ram:ID inside ExchangedDocument in CII.
NormAPI provides technical validation, not tax or legal advice.