Every validation rule, explained

The file must be well-formed XML: every element closed, attributes quoted and only one root element.

The root element must be a UBL 2.1 Invoice or CreditNote, or a UN/CEFACT CrossIndustryInvoice, in the correct namespace.

Amounts, quantities and percentages must be decimal numbers; dates must use the syntax date format (YYYY-MM-DD in UBL, YYYYMMDD with format 102 in CII).

Factur-X / ZUGFeRD MINIMUM and BASIC WL profiles do not carry line items and are not valid EN 16931 invoices.

Document MUST not contain empty elements.

The specification identifier (BT-24) should match the XRechnung standard identifier, e.g. urn:cen.eu:en16931:2017#compliant#urn:xeinkauf.de:kosit:xrechnung_3.0.

An Invoice shall have a Specification identifier (BT-24).

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

An Invoice shall have an Invoice issue date (BT-2).

An Invoice shall have an Invoice type code (BT-3).

An Invoice shall have an Invoice currency code (BT-5).

If both Invoicing period start date (BT-73) and end date (BT-74) are given, the end date shall be later or equal to the start date.

Each Preceding Invoice reference (BG-3) shall contain a Preceding Invoice reference (BT-25).

Value added tax point date (BT-7) and Value added tax point date code (BT-8) are mutually exclusive.

If Invoicing period (BG-14) is used, the Invoicing period start date (BT-73) or the end date (BT-74) shall be filled, or both.

In an Invoice with a VAT breakdown where the category is 'Intra-community supply' the Actual delivery date (BT-72) or the Invoicing period (BG-14) shall not be blank.

The document type code MUST be coded by the invoice and credit note related code lists of UNTDID 1001.

Invoice currency code (BT-5) and VAT accounting currency code (BT-6) MUST be coded using ISO 4217 alpha-3.

Business process MUST be provided.

No more than one note is allowed on document level, unless both supplier and buyer are German organisations.

A buyer reference or purchase order reference MUST be provided.

Specification identifier MUST have the value 'urn:cen.eu:en16931:2017#compliant#urn:fdc:peppol.eu:2017:poacc:billing:3.0'.

VAT accounting currency code MUST be different from invoice currency code when provided.

Business process MUST be in the format 'urn:fdc:peppol.eu:2017:poacc:billing:NN:1.0' where NN indicates the process number.

Invoice type code MUST be set according to the Peppol BIS 3 subset (e.g. 380, 383, 386, 393, 82, 80, 84, 395, 575, 623, 780 …).

Credit note type code MUST be set according to the Peppol BIS 3 subset (81, 83, 261, 262, 296, 308, 381, 396, 420, 458, 532).

An XRechnung must contain the buyer reference (BT-10). For German public buyers this is the Leitweg-ID.

XRechnung expects one of the type codes 326 (partial invoice), 380 (commercial invoice), 384 (corrected invoice), 389 (self-billed invoice), 381 (credit note), 875, 876 or 877 (construction invoices).

An Invoice shall contain the Seller name (BT-27).

An Invoice shall contain the Buyer name (BT-44).

An Invoice shall contain the Seller postal address (BG-5).

The Seller postal address (BG-5) shall contain a Seller country code (BT-40).

An Invoice shall contain the Buyer postal address (BG-8).

The Buyer postal address shall contain a Buyer country code (BT-55).

The Payee name (BT-59) shall be provided if the Payee (BG-10) is different from the Seller.

The Seller tax representative name (BT-62) shall be provided if the Seller has a tax representative.

The Seller tax representative postal address (BG-12) shall be provided if the Seller has a tax representative.

Each Seller tax representative party (BG-11) shall have a Seller tax representative VAT identifier (BT-63).

Each Deliver to address (BG-15) shall contain a Deliver to country code (BT-80).

The Seller electronic address (BT-34) shall have a Scheme identifier.

The Buyer electronic address (BT-49) shall have a Scheme identifier.

The Seller VAT identifier (BT-31), the Seller tax representative VAT identifier (BT-63) and the Buyer VAT identifier (BT-48) shall have a prefix in accordance with ISO code ISO 3166-1 alpha-2 by which the country of issue may be identified. Nevertheless, Greece may use the prefix 'EL'.

In order for the buyer to automatically identify a supplier, the Seller identifier (BT-29), the Seller legal registration identifier (BT-30) and/or the Seller VAT identifier (BT-31) shall be present.

An Invoice that contains a line where the VAT category is 'Standard rated' shall contain the Seller VAT identifier (BT-31), the Seller tax registration identifier (BT-32) and/or the Seller tax representative VAT identifier (BT-63).

An Invoice that contains a line where the VAT category code is 'Reverse charge' shall contain the Seller VAT identifier (or tax representative VAT identifier) and the Buyer VAT identifier (or Buyer legal registration identifier).

An Invoice that contains a line where the VAT category code is 'Intra-community supply' shall contain the Seller VAT identifier (or tax representative VAT identifier) and the Buyer VAT identifier.

In an Invoice with a VAT breakdown where the category is 'Intra-community supply' the Deliver to country code (BT-80) shall not be blank.

An Invoice that contains a line where the VAT category code is 'Export outside the EU' shall contain the Seller VAT identifier (BT-31) or the Seller tax representative VAT identifier (BT-63).

An Invoice that contains a line where the VAT category code is 'Not subject to VAT' shall not contain the Seller VAT identifier, the Seller tax representative VAT identifier or the Buyer VAT identifier.

Country codes in an invoice MUST be coded using ISO code list 3166-1 alpha-2.

Endpoint identifier scheme identifier MUST belong to the CEF EAS code list.

Buyer electronic address MUST be provided.

Seller electronic address MUST be provided.

GLN must have a valid format according to GS1 rules (13 digits with a valid check digit).

The VAT identifier does not match the national format of its country prefix, so tax authorities and VIES will reject it.

The VAT identifier has the right shape but its check digit does not match the national algorithm — it is most likely a typo.

The seller VAT prefix differs from the seller country. This is legitimate for foreign VAT registrations but is a frequent copy-paste error.

The Belgian enterprise number (scheme 0208) does not pass its mod-97 check.

An XRechnung must contain the seller contact group (BG-6).

The seller postal address must contain the city (BT-37).

The seller postal address must contain the post code (BT-38).

The seller contact must contain a contact point (BT-41), e.g. a person or department name.

The seller contact must contain a telephone number (BT-42).

The seller contact must contain an email address (BT-43).

The buyer postal address must contain the city (BT-52).

The buyer postal address must contain the post code (BT-53).

When VAT categories S, Z, E, AE, K, G, L or M are used, the seller VAT identifier (BT-31), the seller tax registration number (BT-32) or the tax representative VAT identifier (BT-63) must be given.

An Invoice shall have at least one Invoice line (BG-25).

Each Invoice line shall have an Invoice line identifier (BT-126).

Each Invoice line shall have an Invoiced quantity (BT-129).

An Invoice line shall have an Invoiced quantity unit of measure code (BT-130).

Each Invoice line shall have an Invoice line net amount (BT-131).

Each Invoice line shall contain the Item name (BT-153).

Each Invoice line shall contain the Item net price (BT-146).

The Item net price (BT-146) shall NOT be negative.

The Item gross price (BT-148) shall NOT be negative.

If both Invoice line period start date (BT-134) and end date (BT-135) are given, the end date shall be later or equal to the start date.

Each Invoice line allowance (BG-27) shall have an Invoice line allowance amount (BT-136).

Each Invoice line allowance (BG-27) shall have a reason (BT-139) or reason code (BT-140).

Each Invoice line charge (BG-28) shall have an Invoice line charge amount (BT-141).

Each Invoice line charge (BG-28) shall have a reason (BT-144) or reason code (BT-145).

Each Item attribute (BG-32) shall contain an Item attribute name (BT-160) and an Item attribute value (BT-161).

The Item standard identifier (BT-157) shall have a Scheme identifier.

The Item classification identifier (BT-158) shall have a Scheme identifier.

Each Invoice line (BG-25) shall be categorized with an Invoiced item VAT category code (BT-151).

If Invoice line period (BG-26) is used, the start date (BT-134) or end date (BT-135) shall be filled, or both.

In an Invoice line where the VAT category code is 'Standard rated' the invoiced item VAT rate (BT-152) shall be greater than zero.

In an Invoice line where the VAT category code is 'Zero rated' the invoiced item VAT rate (BT-152) shall be 0.

In an Invoice line where the VAT category code is 'Exempt from VAT', the invoiced item VAT rate (BT-152) shall be 0.

In an Invoice line where the VAT category code is 'Reverse charge' the invoiced item VAT rate (BT-152) shall be 0.

In an Invoice line where the VAT category code is 'Intra-community supply' the invoiced item VAT rate (BT-152) shall be 0.

In an Invoice line where the VAT category code is 'Export outside the EU' the invoiced item VAT rate (BT-152) shall be 0.

An Invoice line where the VAT category code is 'Not subject to VAT' shall not contain an invoiced item VAT rate (BT-152).

Charge on price level is NOT allowed. Only value 'false' allowed.

Item net price MUST equal (Gross price − Allowance amount) when gross price is provided.

Start date of line period MUST be within invoice period.

End date of line period MUST be within invoice period.

Invoice line net amount MUST equal (Invoiced quantity × (Item net price / item price base quantity) + Sum of invoice line charge amount − sum of invoice line allowance amount.

Base quantity MUST be a positive number above zero.

Unit code of price base quantity MUST be same as invoiced quantity.

The unit of measure code is not in our list of common UN/ECE Recommendation 20/21 codes. It may still be valid.

Each Document level allowance (BG-20) shall have a Document level allowance VAT category code (BT-95).

Each Document level charge (BG-21) shall have a Document level charge VAT category code (BT-102).

Each VAT breakdown (BG-23) shall have a VAT category taxable amount (BT-116).

Each VAT breakdown (BG-23) shall have a VAT category tax amount (BT-117).

Each VAT breakdown (BG-23) shall be defined through a VAT category code (BT-118).

Each VAT breakdown (BG-23) shall have a VAT category rate (BT-119), except if the Invoice is not subject to VAT.

Invoice total VAT amount (BT-110) = Σ VAT category tax amount (BT-117).

VAT category tax amount (BT-117) = VAT category taxable amount (BT-116) × (VAT category rate (BT-119) / 100), rounded to two decimals.

An Invoice shall at least have one VAT breakdown group (BG-23).

An Invoice that contains a line, allowance or charge where the VAT category code is 'Standard rated' shall contain in the VAT breakdown at least one VAT category code equal to 'Standard rated'.

For each different value of VAT category rate (BT-119) where the category is 'Standard rated', the taxable amount (BT-116) shall equal the sum of line net amounts plus charges minus allowances with that category and rate.

A VAT breakdown with VAT category code 'Standard rated' shall not have a VAT exemption reason code (BT-121) or text (BT-120).

A VAT breakdown with category 'Zero rated' shall not have a VAT exemption reason code or text.

A VAT breakdown with VAT category code 'Exempt from VAT' shall have a VAT exemption reason code (BT-121) or a VAT exemption reason text (BT-120).

A VAT breakdown with VAT category code 'Reverse charge' shall have a VAT exemption reason code (BT-121), meaning 'Reverse charge', or the VAT exemption reason text (BT-120) 'Reverse charge'.

A VAT breakdown with VAT category code 'Intra-community supply' shall have a VAT exemption reason code (BT-121) or text (BT-120).

A VAT breakdown with VAT category code 'Not subject to VAT' shall have a VAT exemption reason code (BT-121) or text (BT-120).

For each VAT category and rate, the VAT category taxable amount (BT-116) shall equal the sum of Invoice line net amounts minus document level allowances plus document level charges with that category and rate (BR-Z-08, BR-E-08, BR-AE-08, BR-IC-08, BR-G-08, BR-O-08).

An Invoice that contains a line, allowance or charge with a given VAT category code shall contain a VAT breakdown group with the same category (BR-Z-01, BR-E-01, BR-AE-01, BR-IC-01, BR-G-01, BR-O-01).

Invoice tax categories MUST be coded using UNCL5305 code list (S, Z, E, AE, K, G, O, L, M).

Only one tax total with tax subtotals MUST be provided.

Invoice total VAT amount and Invoice total VAT amount in accounting currency MUST have the same operational sign.

An Invoice shall have the Sum of Invoice line net amount (BT-106).

An Invoice shall have the Invoice total amount without VAT (BT-109).

An Invoice shall have the Invoice total amount with VAT (BT-112).

An Invoice shall have the Amount due for payment (BT-115).

Each Document level allowance (BG-20) shall have a Document level allowance amount (BT-92).

Each Document level allowance (BG-20) shall have a Document level allowance reason (BT-97) or reason code (BT-98).

Each Document level charge (BG-21) shall have a Document level charge amount (BT-99).

Each Document level charge (BG-21) shall have a Document level charge reason (BT-104) or reason code (BT-105).

If the VAT accounting currency code (BT-6) is present, the Invoice total VAT amount in accounting currency (BT-111) shall be provided.

Sum of Invoice line net amount (BT-106) = Σ Invoice line net amount (BT-131).

Sum of allowances on document level (BT-107) = Σ Document level allowance amount (BT-92).

Sum of charges on document level (BT-108) = Σ Document level charge amount (BT-99).

Invoice total amount without VAT (BT-109) = Σ Invoice line net amount (BT-131) − Sum of allowances on document level (BT-107) + Sum of charges on document level (BT-108).

Invoice total amount with VAT (BT-112) = Invoice total amount without VAT (BT-109) + Invoice total VAT amount (BT-110).

Amount due for payment (BT-115) = Invoice total amount with VAT (BT-112) − Paid amount (BT-113) + Rounding amount (BT-114).

Document and line amounts (BT-92, 93, 99, 100, 106–117, 131, 136, 137, 141, 142) shall have a maximum of two decimals (BR-DEC-01 … BR-DEC-28).

Allowance/charge amount must equal base amount × percentage / 100 if base amount and percentage exists.

Allowance/charge base amount MUST be provided when allowance/charge percentage is provided.

Allowance/charge percentage MUST be provided when allowance/charge base amount is provided.

Allowance/charge ChargeIndicator value MUST equal 'true' or 'false'.

All currencyID attributes MUST have the same value as the invoice currency code (BT-5), except for the invoice total VAT amount in accounting currency (BT-111).

A Payment instruction (BG-16) shall specify the Payment means type code (BT-81).

If the Payment means type code (BT-81) means SEPA credit transfer, Local credit transfer or Non-SEPA international credit transfer, the Payment account identifier (BT-84) shall be present.

In case the Amount due for payment (BT-115) is positive, either the Payment due date (BT-9) or the Payment terms (BT-20) shall be present.

Payment means in an invoice MUST be coded using UNCL4461 code list.

Mandate reference MUST be provided for direct debit.

The payment due date is earlier than the invoice issue date.

The payment account looks like an IBAN but its ISO 13616 check digits are invalid.

An XRechnung must contain payment instructions (BG-16), i.e. at least a payment means code.