BR-DE-28 - Seller e-mail address should be well formed
The Seller contact email address (BT-43) should contain exactly one @ sign, flanked by at least two characters on each side and never adjacent to a space or a dot; the address should not start or end with a dot.
BR-DE-28 - Seller e-mail address should be well formed
The Seller contact email address (BT-43) should contain exactly one @ sign, flanked by at least two characters on each side and never adjacent to a space or a dot; the address should not start or end with a dot. This is an XRechnung rule (German KoSIT CIUS). It applies on top of EN 16931 and Peppol, and is mandatory for B2G invoicing in Germany.
What this rule checks
The Seller contact email address (BT-43) should contain exactly one @ sign, flanked by at least two characters on each side and never adjacent to a space or a dot; the address should not start or end with a dot.
How to fix it
Correct BT-43 so that it reads like [email protected].
Validate against this rule
This rule is part of EN 16931. Check your invoice with the validator that matches your format:
Related rules
Source: KoSIT XRechnung · Last verified: 2026-07-10
All validation rules