Validation rules

BR-AE-04 — EN 16931 rule

A document-level charge uses VAT category "AE" (reverse charge), which requires a seller VAT identifier (BT-31), tax registration number (BT-32) or the VAT identifier of a seller tax representative (BT-63) — plus the buyer VAT identifier (BT-48) or the buyer legal registration identifier (BT-47).

Rule: BR-AE-04 — official EN 16931 / XRechnung rule
Severity: error
Business term: BT-48 — Buyer VAT identifier
Field in your JSON: invoice.buyer.vat_id
Detected by: tier 3 — KoSIT validator (authoritative)
Reachability: Triggerable from your request JSON (generate & validate)

How to fix it

Set invoice.buyer.vat_id or invoice.buyer.legal_registration_id, plus invoice.seller.vat_id or invoice.seller.tax_number.

BR-AE-04 auf Deutsch — was bedeutet der Fehler?

Ein Zuschlag auf Dokumentebene verwendet die Kategorie "AE" (Reverse Charge). Dafür sind die USt-IdNr. (BT-31) oder Steuernummer (BT-32) des Verkäufers oder die USt-IdNr. seines Steuervertreters (BT-63) Pflicht — außerdem die USt-IdNr. (BT-48) oder die Handelsregisterkennung (BT-47) des Käufers.

So beheben Sie den Fehler

Setzen Sie invoice.buyer.vat_id oder invoice.buyer.legal_registration_id sowie invoice.seller.vat_id oder invoice.seller.tax_number.

Related rules

BR-AE-02 — Reverse charge (AE) requires a seller VAT identifier (BT-31), tax registration number (BT-32) or the VAT…
BR-AE-03 — A document-level allowance uses VAT category "AE" (reverse charge), which requires a seller VAT identifier…
BR-IC-02 — The invoice has intra-community supply (K) lines, which require the buyer VAT identifier (BT-48) plus either…
BR-IC-03 — A document-level allowance uses VAT category K (intra-community supply), which requires the buyer VAT…
BR-IC-04 — A document-level charge uses VAT category K (intra-community supply), which requires the buyer VAT…
UBL-SR-18 — The buyer VAT identifier (BT-48) appears more than once — only one PartyTaxScheme with TaxScheme/ID 'VAT'…

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.