BR-02

EN 16931 FATAL

Official rule text

An Invoice shall have an Invoice number (BT-1).

What this error means

Every invoice must have an Invoice number (BT-1, cbc:ID). It is the primary key of the document - validators reject the file outright when it is missing or empty.

How to fix it

Add cbc:ID with your invoice number, e.g. INV-2026-0042.
Keep it unique per seller - duplicates cause rejections downstream, not here.
Do not confuse it with the buyer reference (BT-10) or order reference (BT-13).

Related rules

Fix it faster

Paste your invoice XML in our free validator - every finding comes with its rule ID. Then generate, convert and render compliant invoices through one API.

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