BR-DE-15Das Element "Buyer reference" (BT-10) muss übermittelt werden.
Official rule text
Every XRechnung needs a buyer reference in BT-10 — for invoices to a German public authority that is the Leitweg-ID. It routes the invoice to the right office. All that is checked, though, is that the field is not empty: the rule set never looks at its structure or its check digit.
- Severity
- Error
- Applies to
- CII, UBL
- Rule set
- v2026-08-31
- Checked on
Written and checked against the official KoSIT rule set by Dmytro Yalanskyi, NormAPI.
Why does BR-DE-15 happen?
It is usually missing because an existing B2B invoice template was reused: buyer reference is rarely needed there, but XRechnung makes it mandatory. The check does not help with the real risk — the only expression in the whole rule set that touches BT-10 is this existence test. "Test", or a Leitweg-ID that is out of date, passes validation and fails later at the receiving portal, which does not recognise the route.
What the validator checks
The expression the official KoSIT rule set evaluates — not paraphrased, but read from the Schematron file it ships. UBL and CII address different document trees, so the same rule reads differently in each.
- UBL
cbc:BuyerReference[boolean(normalize-space(.))]- CII
rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeAgreement/ram:BuyerReference[boolean(normalize-space(.))]
Source: rule set v2026-08-31
How do you fix BR-DE-15?
Put the Leitweg-ID or buyer reference supplied by your customer into BT-10 — cbc:BuyerReference in UBL, ram:BuyerReference in CII. The field is mandatory for B2B invoices too: there it carries whatever reference the buyer asked for, an order number for instance.
In the XML
A UBL fragment. The CII path is named above — same change, different element names.
<cbc:InvoiceTypeCode>380</cbc:InvoiceTypeCode>
<cbc:DocumentCurrencyCode>EUR</cbc:DocumentCurrencyCode><cbc:InvoiceTypeCode>380</cbc:InvoiceTypeCode>
<cbc:DocumentCurrencyCode>EUR</cbc:DocumentCurrencyCode>
<cbc:BuyerReference>04011000-12345-03</cbc:BuyerReference>Related rules
NormAPI provides technical validation, not tax or legal advice.