NLCIUS (Netherlands Core Invoice Usage Specification) is the Dutch implementation of the European e-invoice standard EN 16931. It is the mandatory standard for e-invoicing to Dutch government bodies and the recommended standard for B2B invoicing in the Netherlands.

NLCIUS is a CIUS (Core Invoice Usage Specification): a country-specific implementation of Peppol BIS Billing 3.0. It adds Dutch business rules on top of the European standard. An invoice that complies with NLCIUS automatically complies with Peppol BIS Billing V3 and with EN 16931.

The standard is also known as SI-UBL 2.0 (Simplerinvoicing UBL 2.0). This is the same standard; NLCIUS is the official name, SI-UBL 2.0 the historical name.

NLCIUS primarily defines a semantic model: it describes what information a Dutch e-invoice must contain and which rules apply. Formally, NLCIUS is syntax-independent. Both UBL 2.1 and UN/CEFACT CII are permitted as the underlying XML structure. In practice, UBL 2.1 (in the form of SI-UBL 2.0) is by far the most widely used in the Netherlands, and it is also the format that most software vendors and Peppol receivers work with.

NLCIUS is managed through the NEN Standards Committee on e-invoicing, the Dutch representative in Europe regarding the European Standard EN 16931. This standards committee is facilitated by NEN (the Netherlands Standardisation Institute). Previously, management was handled by STPE (Stichting Peppol Eindgebruikers).

eConnect is an active member of this standards committee. This means that eConnect is directly involved in the development and maintenance of the Dutch e-invoicing standard and contributes to alignment with the European Standard EN 16931.

The DocumentTypeId uniquely identifies the invoice format on the Peppol network. For NLCIUS this is:

urn:oasis:names:specification:ubl:schema:xsd:Invoice-2::Invoice##urn:cen.eu:en16931:2017#compliant#urn:fdc:nen.nl:nlcius:v1.0::2.1

This DocumentTypeId is used for SMP registration, routing and sending/receiving via the PSB.

NLCIUS adds specific rules relevant to the Dutch market:

The G-account extension makes it possible to send invoices with a blocked account, as required in the construction sector. This uses a separate DocumentTypeId:

urn:oasis:names:specification:ubl:schema:xsd:Invoice-2::Invoice##urn:cen.eu:en16931:2017#compliant#urn:fdc:nen.nl:nlcius:v1.0#conformant#urn:fdc:nen.nl:gaccount:v1.0::2.1

The G-account is included as a separate payment component in the invoice. Depending on whether the receiver supports the G-account extension, one or two invoices are generated.

NLCIUS uses the EN 16931/UNCL5305 codes for VAT categories:

The predecessor of NLCIUS, SI-UBL 1.2 (Simplerinvoicing 1.2), was permanently discontinued as of 1 January 2024. Invoices in this format are rejected on the Peppol network. If you are still using SI-UBL 1.2, you must upgrade to NLCIUS/SI-UBL 2.0 or Peppol BIS Billing V3.

You can validate your invoices against NLCIUS in two ways:

• Free online validator: available on the eConnect website. Upload your XML and receive instant feedback.
• Validate API: via POST /api/v1/generic/validate in the PSB. Validates automatically against the correct standard, including customer-specific rules.

The PSB uses a dual validation layer: first the most recent artefacts are checked, and if those are not valid but the previous version is still accepted, the previous version is also checked.

Sample files for NLCIUS invoices are available in the PSB documentation. These templates contain correct invoice structures that you can use as a basis for your own implementation.

Want to test your invoice against NLCIUS? Use the Validate API or the free online validator.

• NLCIUS with G-account (construction)
• SEEF: the Standard Energy e-Invoice
• The structure of a UBL invoice
• Peppol Party Identifiers per country
• DocumentType IDs and code lists
• What is the difference between XML, UBL, BIS Billing V3 and NLCIUS?