> ## Documentation Index
> Fetch the complete documentation index at: https://docs.gobl.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Danish OIOUBL 2.1

Key: `dk-oioubl-v2`

Module: [github.com/invopop/gobl.dk.oioubl](https://github.com/invopop/gobl.dk.oioubl)

Support for the Danish OIOUBL 2.1 standard used on the NemHandel
e-invoicing network, mandatory for business-to-government (B2G)
transactions in Denmark since 2005.

OIOUBL 2.1 is a national profile of UBL 2.1, maintained by
Erhvervsstyrelsen (the Danish Business Authority). Unlike many
European profiles it predates and does not extend EN 16931.

This addon translates the OIOUBL Schematron rules (v1.17.2, the
hotfix live since 2026-05-18) into GOBL
validations. OIOUBL 2.1 is scheduled to be replaced by NemHandel
BIS 4 starting in 2028.

## Sources

* [OIOUBL 2.1 documentation overview](https://nemhandel.dk/vejledning-oioubl-dokumentationsoversigt)
* [OIOUBL Schematron v1.17.2 (hotfix, live 2026-05-18)](https://git.erst.dk/openebusiness/common/-/tree/master/released/oioubl)
* [OIOUBL Schematron rules (browsable source, referenced by rule citations)](https://git.erst.dk/openebusiness/common/-/tree/master/resources/Schematrons/OIOUBL?ref_type=heads)

## Extensions

### SKAT excise duty code

Code identifying a Danish excise duty ("punktafgift") from the SKAT
tax scheme codelist (OIOUBL `urn:oioubl:id:taxschemeid`), set on a
document or line charge whose key is `excise`. OIOUBL emits the
charge as its own `cac:TaxTotal` with this code as the
`cac:TaxScheme/cbc:ID`.

For example, `16` is the duty on chocolate and confectionery
("Chokolade- og sukkervarerafgift") and `66` the vehicle
registration tax ("Registreringsafgift af motorkøretøjer").

The value set is deliberately left open: the codelist has both
gained and lost codes across taxschemeid versions, and includes
non-numeric codes (e.g. `21d`).

<Accordion title="dk-oioubl-duty-code" />

## Validation Rules

<AccordionGroup>
  <Accordion title="bill.Invoice">
    | Field                | Test                                                                                    | Validation Code / Message                                                                                                                                                             |
    | -------------------- | --------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
    | `tax.ext`            | <ul class="gobl-test"><li>Ext 'untdid-document-type' in \[325, 380, 381, 393]</li></ul> | `GOBL-DK-OIOUBL-BILL-INVOICE-01`<br />Tax extension 'untdid-document-type' must use a document type OIOUBL supports: 325, 380 or 393 for an invoice, 381 for a credit note (F-INV011) |
    | `tax.rounding`       | <ul class="gobl-test"><li>One of \[currency]</li></ul>                                  | `GOBL-DK-OIOUBL-BILL-INVOICE-02`<br />Amounts must be rounded per currency so the emitted lines sum to the document totals (F-INV126)                                                 |
    | `customer.endpoints` | <ul class="gobl-test"><li class="gobl-test-present">Present</li></ul>                   | `GOBL-DK-OIOUBL-BILL-INVOICE-03`<br />Customer endpoint is required (F-INV044 / F-CRN040)                                                                                             |
    | `lines[*]`           | <ul class="gobl-test"><li>Line has tax category VAT</li></ul>                           | `GOBL-DK-OIOUBL-BILL-INVOICE-04`<br />Each line requires a VAT tax category (F-INV138 / F-CRN081)                                                                                     |
    | `charges[*].taxes`   | <ul class="gobl-test"><li>String(Key) != "excise"</li><li>All of \[VAT]</li></ul>       | `GOBL-DK-OIOUBL-BILL-INVOICE-05`<br />Document-level charge requires a VAT tax for the OIOUBL TaxCategory (F-LIB226)                                                                  |
  </Accordion>

  <Accordion title="tax.Combo">
    | Field | Test                                                     | Validation Code / Message                                                                |
    | ----- | -------------------------------------------------------- | ---------------------------------------------------------------------------------------- |
    | `key` | <ul class="gobl-test"><li>Not one of \[exempt]</li></ul> | `GOBL-DK-OIOUBL-TAX-COMBO-01`<br />OIOUBL has no exempt VAT category (taxcategoryid-1.1) |
  </Accordion>

  <Accordion title="bill.Charge">
    | Field    | Test                                                                                                   | Validation Code / Message                                                                                                                       |
    | -------- | ------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------- |
    | `reason` | <ul class="gobl-test"><li>String(Key) == "excise"</li><li class="gobl-test-present">Present</li></ul>  | `GOBL-DK-OIOUBL-BILL-CHARGE-01`<br />An OIOUBL excise duty charge requires a reason for its tax-scheme name (F-LIB066)                          |
    | `taxes`  | <ul class="gobl-test"><li>String(Key) == "excise"</li><li>All of \[VAT]</li></ul>                      | `GOBL-DK-OIOUBL-BILL-CHARGE-02`<br />A document-level OIOUBL excise duty requires a VAT tax stating its own VAT type (OIOUBL Skat guideline)    |
    | `ext`    | <ul class="gobl-test"><li>String(Key) == "excise"</li><li>Ext require \[dk-oioubl-duty-code]</li></ul> | `GOBL-DK-OIOUBL-BILL-CHARGE-03`<br />An excise duty charge requires the 'dk-oioubl-duty-code' extension, which becomes the OIOUBL tax-scheme ID |
  </Accordion>

  <Accordion title="bill.LineCharge">
    | Field    | Test                                                                                                   | Validation Code / Message                                                                                                                           |
    | -------- | ------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------- |
    | `reason` | <ul class="gobl-test"><li>String(Key) == "excise"</li><li class="gobl-test-present">Present</li></ul>  | `GOBL-DK-OIOUBL-BILL-LINECHARGE-01`<br />An OIOUBL excise duty charge requires a reason for its tax-scheme name (F-LIB066)                          |
    | `ext`    | <ul class="gobl-test"><li>String(Key) == "excise"</li><li>Ext require \[dk-oioubl-duty-code]</li></ul> | `GOBL-DK-OIOUBL-BILL-LINECHARGE-02`<br />An excise duty charge requires the 'dk-oioubl-duty-code' extension, which becomes the OIOUBL tax-scheme ID |
  </Accordion>

  <Accordion title="pay.Instructions">
    | Field                         | Test                                                                                                                                     | Validation Code / Message                                                                                                               |
    | ----------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------- |
    | `ext`                         | <ul class="gobl-test"><li>Ext 'untdid-payment-means' in \[1, 10, 20, 31, 42, 48, 49, 50, 58, 59, 93, 97]</li></ul>                       | `GOBL-DK-OIOUBL-PAY-INSTRUCTIONS-01`<br />Tax extension 'untdid-payment-means' must use a payment means code OIOUBL supports (F-LIB100) |
    | `credit_transfer[*].clearing` | <ul class="gobl-test"><li>Domestic bank transfer (means 42)</li><li class="gobl-test-present">Present</li><li>Matches ^\d{4}\$</li></ul> | `GOBL-DK-OIOUBL-PAY-INSTRUCTIONS-02`<br />A domestic transfer needs a four-digit bank clearing code (F-LIB124 / F-LIB130)               |
  </Accordion>
</AccordionGroup>