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error Class A

BR-DE-03 Seller Contact Email

What this rule checks

BR-DE-03 verifies that the field BT-43 (Seller contact email address) is present in the invoice. Technically, it checks whether the cbc:ElectronicMail element exists within cac:AccountingSupplierParty/cac:Party/cac:Contact and is not empty.

Why this rule exists

The seller’s email address is a mandatory field in the German e-invoicing landscape that goes beyond the European base standard EN 16931. The rationale: in addition to the telephone (BR-DE-02), email provides a second, asynchronous communication channel through which the invoice recipient can reach the invoicing party.

Email is particularly suitable for:

  • Documented inquiries where a written record is required
  • Cases where telephone contact cannot be established
  • Machine-readable communication between ERP systems
  • International business relationships across time zones

Together with BR-DE-02 (telephone) and BR-DE-06 (contact name), BR-DE-03 forms the requirement for a complete seller contact block.

What triggers a failure

The rule fails when:

  • The cbc:ElectronicMail element in the cac:AccountingSupplierParty/cac:Party/cac:Contact block is missing
  • The cbc:ElectronicMail element is present but empty
  • The entire cac:Contact block is missing (this simultaneously triggers BR-DE-02, BR-DE-03, and BR-DE-06)

Failing XML example

The following example shows a seller contact block with a name and telephone but no email address:

<cac:AccountingSupplierParty>
  <cac:Party>
    <cac:PartyName>
      <cbc:Name>Beispiel AG</cbc:Name>
    </cac:PartyName>
    <cac:PostalAddress>
      <cbc:StreetName>Industrieweg 5</cbc:StreetName>
      <cbc:CityName>Stuttgart</cbc:CityName>
      <cbc:PostalZone>70173</cbc:PostalZone>
      <cac:Country>
        <cbc:IdentificationCode>DE</cbc:IdentificationCode>
      </cac:Country>
    </cac:PostalAddress>
    <cac:PartyTaxScheme>
      <cbc:CompanyID>DE987654321</cbc:CompanyID>
      <cac:TaxScheme>
        <cbc:ID>VAT</cbc:ID>
      </cac:TaxScheme>
    </cac:PartyTaxScheme>
    <cac:PartyLegalEntity>
      <cbc:RegistrationName>Beispiel AG</cbc:RegistrationName>
    </cac:PartyLegalEntity>
    <cac:Contact>
      <cbc:Name>Anna Schmidt</cbc:Name>
      <cbc:Telephone>+49 711 9876543</cbc:Telephone>
      <!-- ERROR: Email address is missing -->
    </cac:Contact>
  </cac:Party>
</cac:AccountingSupplierParty>

The fix

Add the cbc:ElectronicMail element to the seller’s Contact block:

<cac:AccountingSupplierParty>
  <cac:Party>
    <cac:PartyName>
      <cbc:Name>Beispiel AG</cbc:Name>
    </cac:PartyName>
    <cac:PostalAddress>
      <cbc:StreetName>Industrieweg 5</cbc:StreetName>
      <cbc:CityName>Stuttgart</cbc:CityName>
      <cbc:PostalZone>70173</cbc:PostalZone>
      <cac:Country>
        <cbc:IdentificationCode>DE</cbc:IdentificationCode>
      </cac:Country>
    </cac:PostalAddress>
    <cac:PartyTaxScheme>
      <cbc:CompanyID>DE987654321</cbc:CompanyID>
      <cac:TaxScheme>
        <cbc:ID>VAT</cbc:ID>
      </cac:TaxScheme>
    </cac:PartyTaxScheme>
    <cac:PartyLegalEntity>
      <cbc:RegistrationName>Beispiel AG</cbc:RegistrationName>
    </cac:PartyLegalEntity>
    <cac:Contact>
      <cbc:Name>Anna Schmidt</cbc:Name>
      <cbc:Telephone>+49 711 9876543</cbc:Telephone>
      <!-- CORRECT: Email address added -->
      <cbc:ElectronicMail>rechnung@beispiel-ag.de</cbc:ElectronicMail>
    </cac:Contact>
  </cac:Party>
</cac:AccountingSupplierParty>

Edge cases and common mistakes

Syntactically valid email required: The value of cbc:ElectronicMail must be a syntactically valid email address (e.g., rechnung@firma.de). Values such as not available or N/A are typically rejected by validation tools, even though BR-DE-03 itself only checks for the presence of the element.

Functional email addresses recommended: A personal email address is not required. Functional addresses such as rechnung@firma.de, buchhaltung@firma.de, or invoicing@firma.de are explicitly permitted and even recommended, as they continue to work through staff changes.

Satisfy BR-DE-02 and BR-DE-03 together: Since both telephone and email are mandatory, a common mistake is to fill in only one of the two fields. A complete Contact block looks like this:

<cac:Contact>
  <cbc:Name>Accounting Department</cbc:Name>
  <cbc:Telephone>+49 711 9876543</cbc:Telephone>
  <cbc:ElectronicMail>rechnung@beispiel-ag.de</cbc:ElectronicMail>
</cac:Contact>

BR-DE-06 — Contact name: In addition to telephone and email, BR-DE-06 requires that cbc:Name (BT-41) is also present in the Contact block. These three elements together form the minimum scope of the seller contact under XRechnung.

XPath: The exact path for validation is:

/ubl:Invoice/cac:AccountingSupplierParty/cac:Party/cac:Contact/cbc:ElectronicMail

For CII (Cross Industry Invoice):

/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeAgreement/ram:SellerTradeParty/ram:DefinedTradeContact/ram:EmailURIUniversalCommunication/ram:URIID

Distinction from BT-49 (EndpointID): The email address in the Contact block (BT-43) serves human communication. It should not be confused with the electronic endpoint (BT-49) used for machine-level invoice routing — even though both can contain an email address.