Peppol glossary

The Peppol ecosystem has its own vocabulary. If you are implementing e-invoicing for the first time, the abbreviations and concepts can be overwhelming. This glossary defines the most important terms you will encounter when working with Peppol, EN 16931 and European e-invoicing standards.

By Peppol Validator · Last updated 10 April 2026

A

Access Point

A certified service provider that connects businesses to the Peppol network. Access Points handle the sending and receiving of electronic documents (invoices, credit notes, orders) on behalf of their customers. Every business on the Peppol network connects through an Access Point. Think of it as your on-ramp to the Peppol highway. Access Points must be certified by a Peppol Authority and comply with the Peppol Transport Infrastructure specifications.

AS4

The messaging protocol used by Peppol for document exchange between Access Points. AS4 (Applicability Statement 4) is based on OASIS ebMS 3.0 and replaced the older AS2 protocol in the Peppol network. It supports reliable messaging, digital signatures and encryption.

See also: The Peppol network.

B

BIS (Business Interoperability Specification)

A Peppol document specification that defines how a particular business process (like invoicing) should work. Peppol BIS Billing 3.0 is the specification for invoices and credit notes. It builds on the EN 16931 standard and adds Peppol-specific business rules. When you validate an invoice with Peppol Validator, the BIS rules are the ones prefixed with PEPPOL-EN16931-*.

Business Rules (BR)

Validation rules defined by the EN 16931 standard. They ensure an invoice is semantically correct. For example, BR-01 requires that an invoice must have a specification identifier, and BR-CO-10 requires that the sum of line amounts equals the total. The full list of all 311 EN 16931 and Peppol BIS rules has explanations and fix guides on the validation errors reference.

C

CEN (European Committee for Standardization)

The standards body that developed EN 16931. CEN Technical Committee 434 is responsible for the European e-invoicing standard. CEN operates through national standards bodies in each EU member state.

CII (Cross-Industry Invoice)

An XML invoice format maintained by UN/CEFACT. CII is one of the two syntax bindings for EN 16931, alongside UBL. While Peppol uses UBL exclusively, CII is common in the DACH region (Germany, Austria, Switzerland) through formats like Factur-X and ZUGFeRD.

CIUS (Core Invoice Usage Specification)

A national or regional restriction of the EN 16931 standard. A CIUS can tighten rules (e.g. make an optional field mandatory) but cannot loosen them. Examples include XRechnung (Germany), Peppol BIS Billing 3.0 and EHF (Norway). Each CIUS ensures EN 16931 compliance while adding jurisdiction-specific requirements.

Credit Note

A document issued to correct or cancel a previously sent invoice. In Peppol, credit notes follow the same BIS Billing 3.0 specification as invoices and are validated against the same rules.

D

Document Type Identifier

A Peppol identifier that specifies the type of document being exchanged. For Peppol BIS Billing 3.0 invoices, the identifier is urn:oasis:names:specification:ubl:schema:xsd:Invoice-2::Invoice##urn:cen.eu:en16931:2017#compliant#urn:fdc:peppol.eu:2017:poacc:billing:3.0::2.1. This identifier tells the receiving Access Point what kind of document to expect.

See also: The Peppol network.

E

EAS (Electronic Address Scheme)

A code list that identifies the type of electronic address used in Peppol. Common EAS codes include 0106 (Dutch KvK number), 0190 (Dutch OIN), 0208 (Belgian enterprise number) and 9925 (Swedish organization number). The EAS code is part of the Participant Identifier.

EHF (Elektronisk Handelsformat)

Norway's national e-invoicing CIUS based on Peppol BIS Billing 3.0. EHF is the format used for Norwegian B2G and B2B e-invoicing through the Peppol network. Norway has been one of the most mature Peppol markets in Europe and made B2G e-invoicing mandatory back in 2019.

EN 16931

The European standard for the semantic data model of an electronic invoice. Published by CEN in 2017, it defines what information an e-invoice must and may contain. EN 16931 does not mandate a specific file format. Instead, it has two official syntax bindings: UBL 2.1 and CII. All European e-invoicing mandates reference EN 16931 as the core standard. The business rules (BR-*) that the Peppol Validator checks come from EN 16931.

F

Factur-X

A hybrid e-invoice format jointly developed by France (FNFE-MPE) and Germany (FeRD). Factur-X embeds a CII XML file inside a PDF/A-3 document, making it both human-readable (the PDF) and machine-readable (the XML). It is functionally identical to ZUGFeRD 2.x.

Five-Corner Model

An extension of the four-corner model where a tax authority acts as a fifth corner. In continuous transaction controls (CTC) systems, the invoice passes through or is reported to the tax authority in real or near-real time. Italy's SDI system is the most prominent example. The EU's ViDA initiative may introduce elements of this model across Europe; Belgium will introduce it for tax e-reporting on 1 January 2028.

Four-Corner Model

The architecture of the Peppol network. The four corners are: Corner 1 the sender (e.g. the supplier's ERP system), Corner 2 the sender's Access Point, Corner 3 the receiver's Access Point and Corner 4 the receiver (e.g. the buyer's accounting system). Documents flow from Corner 1 to Corner 4 through the two Access Points, which handle routing, validation and delivery.

I

Invoice Response

A Peppol document type (BIS 3.0 IMR) that allows the receiver to communicate the processing status of an invoice back to the sender. Statuses include accepted, rejected, conditionally accepted and under query. Not all Access Points support Invoice Response.

M

MLR (Message Level Response)

A technical acknowledgement that the receiver Access Point sends back to the sender Access Point after receiving and validating an AS4 message. The MLR confirms that the document was received, that the AS4 envelope was well-formed and whether the payload passed schematron validation. The sender knows from the MLR whether to consider the delivery complete.

O

OpenPeppol

The non-profit association that governs the Peppol network. Based in Brussels, OpenPeppol maintains the specifications, manages the trust framework and coordinates with Peppol Authorities worldwide. Members include government agencies, Access Point providers and software vendors.

See also: The Peppol network.

P

Participant Identifier

The unique address of a business on the Peppol network. It consists of a scheme (EAS code) and a value. For example, a Belgian company might be identified as 0208:0123456789 where 0208 is the EAS code for Belgian enterprise numbers.

See also: The Peppol network.

Peppol Authority

A national or regional organization authorized by OpenPeppol to certify and monitor Access Points in their jurisdiction. Examples include the Belgian Peppol Authority, the Norwegian Digdir, the Australian ATO and Singapore's IMDA.

Peppol BIS Billing 3.0

The Peppol Business Interoperability Specification for invoices and credit notes. It is a CIUS on top of EN 16931, uses UBL 2.1 as the XML syntax and adds Peppol-specific business rules (the PEPPOL-EN16931-* family). It is the default invoice format on the Peppol network.

Peppol Directory

A public lookup service where businesses can register their Peppol capabilities. It allows senders to discover which document types a receiver supports. Available at directory.peppol.eu.

See also: The Peppol network.

PINT (Peppol International)

A newer invoice model designed for use outside Europe. PINT adapts the Peppol invoice for jurisdictions like Australia, New Zealand, Singapore and Japan with country-specific extensions. It coexists with BIS Billing 3.0 but is tailored for non-EU requirements.

S

Schematron

An XML validation language used to enforce business rules. The Peppol and EN 16931 validation rules are written as Schematron files (.sch), which are compiled into XSLT stylesheets for execution. The Peppol Validator uses compiled Schematron rules (SEF format) to validate invoices via SaxonJS.

SDI (Sistema di Interscambio)

Italy's centralised e-invoicing platform run by the Italian Revenue Agency (Agenzia delle Entrate). Every B2B and B2G invoice in Italy must pass through SDI before reaching the buyer. SDI is older than the Peppol five-corner model and uses the country-specific FatturaPA XML format rather than UBL or CII.

SML (Service Metadata Locator)

A DNS-based lookup service in the Peppol network. When an Access Point needs to find another participant, it first queries the SML to discover where that participant's metadata is stored. The SML returns a pointer to the participant's SMP.

SMP (Service Metadata Publisher)

A registry that stores a Peppol participant's capabilities: which document types they can receive, which processes they support and the technical endpoint of their Access Point. Each participant has one SMP entry, managed by their Access Point.

SVRL (Schematron Validation Report Language)

The XML output format produced when Schematron rules are applied to a document. SVRL reports contain fired-rule, successful-report and failed-assert elements that indicate which rules passed and which failed. The Peppol Validator parses SVRL output to generate human-readable validation results.

U

UBL (Universal Business Language)

An XML document format maintained by OASIS. UBL 2.1 is one of the two official syntax bindings for EN 16931 and is the format required by Peppol. A UBL invoice uses namespaces like urn:oasis:names:specification:ubl:schema:xsd:Invoice-2 and structures data in elements like cac:AccountingSupplierParty and cbc:InvoiceTypeCode.

V

ViDA (VAT in the Digital Age)

An EU initiative to modernise VAT reporting through mandatory e-invoicing and real-time digital reporting. ViDA aims to establish EU-wide e-invoicing requirements by 2030, building on EN 16931. It will likely make Peppol (or a Peppol-compatible approach) the standard for cross-border B2B invoicing in the EU.

X

XRechnung

Germany's national e-invoicing standard, based on EN 16931 with additional German-specific rules (CIUS). XRechnung uses the UBL or CII syntax and is mandatory for invoices to German public-sector entities.

Z

ZUGFeRD

The German hybrid e-invoice format, developed by the Forum elektronische Rechnung Deutschland (FeRD). ZUGFeRD 2.x is technically identical to Factur-X: a CII XML file embedded in a PDF/A-3 document. ZUGFeRD 2.0+ conforms to EN 16931 at its EN 16931 profile. Earlier versions (ZUGFeRD 1.0) used a different, non-EN 16931 data model.

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