Peppol and EN 16931 are the two building blocks of e-invoicing across Europe. EN 16931 defines what goes into an invoice: the required data fields, the structure, and the rules. Peppol defines how that invoice gets delivered, covering the network, the routing, and the access points. Together, they enable businesses to exchange structured electronic invoices across borders, languages, and accounting systems without bilateral agreements or proprietary formats.
In short: EN 16931 is the "what" of European e-invoicing. Peppol is the "how." Businesses that understand both are better prepared for the wave of national e-invoicing mandates now rolling out across the EU.
What is EN 16931?
EN 16931 is the European standard for electronic invoice data. Published by the European Committee for Standardisation (CEN) in 2017, it defines a semantic data model for the core elements of an e-invoice: seller and buyer information, line items, tax breakdowns, payment terms, and totals. It was created to fulfil the requirements of EU Directive 2014/55/EU, which mandates that all public sector entities in the EU must be able to receive and process electronic invoices that conform to this standard.
A common misconception is that EN 16931 is a file format. It is not. It is a data model, specifically a set of business rules and field definitions that describe what information an e-invoice must contain. The standard specifies which fields are required (such as invoice number, issue date, seller VAT ID, and total amount) and which are optional (such as delivery date or purchase order reference). It also defines validation rules, for example that tax category codes must match the corresponding tax amounts.
EN 16931 maps to two supported XML syntaxes:
- •UBL 2.1 (Universal Business Language), maintained by OASIS. This is the more widely adopted syntax, used by Peppol BIS Billing 3.0, XRechnung, and several national implementations.
- •UN/CEFACT CII (Cross Industry Invoice), maintained by the United Nations. This syntax is used by ZUGFeRD/Factur-X and some French implementations.
Both syntaxes carry the same semantic content. An EN 16931-compliant invoice expressed in UBL contains the same business information as one expressed in CII, just in a different XML structure. This dual-syntax approach was a pragmatic compromise to accommodate existing implementations across Europe.
What is Peppol?
Peppol (Pan-European Public Procurement OnLine) started as an EU-funded pilot project in 2008, designed to simplify cross-border public procurement. It has since evolved into a global network for exchanging structured business documents, including invoices, credit notes, and purchase orders. The network is now governed by OpenPeppol, a non-profit international association based in Brussels.
The core concept behind Peppol is the 4-corner model. Rather than requiring every business to establish a direct connection with every trading partner, Peppol introduces intermediaries called Access Points. The flow works as follows:
- •Corner 1: The sender (the business issuing the invoice)
- •Corner 2: The sender’s Access Point (a certified service provider that transmits the document onto the Peppol network)
- •Corner 3: The receiver’s Access Point (a certified provider that receives the document and delivers it to the recipient)
- •Corner 4: The receiver (the business receiving the invoice)
Businesses do not connect directly to the Peppol network. Instead, they connect through an Access Point provider, much like connecting to the internet through an ISP. The Access Point handles routing, security, and compliance. The Peppol network uses a central directory called the SMP (Service Metadata Publisher) to look up where each participant can be reached, based on their business identifier (such as a VAT number or company registration number).
This architecture means that a business in Belgium can send an invoice to a business in Norway without either party needing to know anything about the other’s technical setup. The Access Points handle everything in between.
How EN 16931 and Peppol Work Together
EN 16931 and Peppol solve different parts of the same problem. EN 16931 standardises the content of an invoice. Peppol standardises the delivery mechanism. Neither is complete without the other.
The bridge between them is Peppol BIS Billing 3.0, a specification maintained by OpenPeppol that defines exactly how an EN 16931-compliant invoice should be formatted for transmission over the Peppol network. In technical terms, Peppol BIS Billing 3.0 is a CIUS (Core Invoice Usage Specification) - a constrained implementation of EN 16931 that adds Peppol-specific rules on top of the base standard. For example, it requires the use of UBL 2.1 syntax and specifies certain code lists and identifier schemes that must be used for routing on the network.
Think of it this way: EN 16931 defines the language of e-invoicing. Peppol BIS Billing 3.0 is a specific dialect of that language, optimised for the Peppol postal system. And the Peppol network itself is the postal system that carries the message from sender to receiver.
Common E-Invoice Formats
Several e-invoice formats are in use across Europe. Most are built on or compatible with EN 16931, but they differ in syntax, scope, and national requirements.
| Format | Syntax | Region | EN 16931 | Notes |
|---|---|---|---|---|
| Peppol BIS Billing 3.0 | UBL 2.1 | International | Yes (CIUS) | Default format on the Peppol network |
| XRechnung | UBL 2.1 | Germany | Yes (CIUS) | Mandatory for German B2G, used in B2B |
| ZUGFeRD / Factur-X | UN/CEFACT CII | Germany, France | Yes | Hybrid format: structured XML embedded in a PDF |
| FatturaPA | Proprietary XML | Italy | No | Routed through Italy’s SDI clearance system |
The trend is clear: most new national mandates are converging on EN 16931-compliant formats delivered over Peppol. Italy’s FatturaPA is the notable exception, having predated the standard, though Italy is now also exploring Peppol integration. For more on Italy’s system, see our overview of Italy’s SDI e-invoicing model.
Which Countries Use Peppol?
Peppol adoption is accelerating across Europe. Several countries have made it mandatory or are incorporating it into their national e-invoicing infrastructure.
- •Belgium: Mandatory Peppol-BIS for all domestic B2B invoicing from January 2026. The government’s Hermes bridge was retired at the end of 2025.
- •Greece: Mandatory Peppol for B2G e-invoicing from February 2026, integrated with the myDATA real-time reporting platform.
- •France: Became a Peppol Authority in July 2025. Peppol is one of the accepted channels for the national e-invoicing mandate rolling out from September 2026.
- •Germany: The GEBA (German E-Invoicing Business Address) registry operates on Peppol infrastructure. Peppol adoption is voluntary but growing rapidly alongside the B2B mandate.
- •Denmark: NemHandel, the national e-invoicing system, has been integrated with Peppol, allowing Danish businesses to exchange documents with international partners through the same infrastructure.
- •Poland: Exploring Peppol integration alongside its KSeF (National e-Invoice System) as part of its broader digital tax strategy.
Beyond Europe, Peppol is also used in Australia, New Zealand, Singapore, and Japan. The network’s international governance structure makes it well suited for cross-border document exchange, which is one reason the EU’s ViDA initiative is considering Peppol as a foundation for harmonised digital reporting across member states.
How to Connect to Peppol
Connecting to the Peppol network is straightforward for most businesses. The process typically involves three steps:
- •Choose an Access Point provider. These are certified intermediaries that connect your business to the Peppol network. Many ERP vendors and accounting software providers either operate their own Access Point or partner with one. OpenPeppol maintains a directory of certified providers.
- •Register with your business identifier. On the Peppol network, each participant is identified by a unique ID, typically based on your national business number or VAT registration. In Belgium this is the KBO/BCE number, in Germany the Leitweg-ID for public entities, and so on. Your Access Point provider will handle the registration.
- •Configure your ERP or accounting software. Most modern accounting platforms support Peppol BIS Billing 3.0 output natively or through plugins. Your Access Point provider can advise on integration options, whether that means a direct API connection, an email-based gateway, or a web portal for manual invoice submission.
Tip: If your business operates in multiple EU countries, a single Access Point provider can often handle all your Peppol traffic. This is one of the key advantages of the network, since you do not need a separate setup for each country.
E-Invoicing and SAF-T: Related but Different
Peppol and EN 16931 address invoice exchange between businesses. The OECD’s Standard Audit File for Tax (SAF-T) addresses a different need: providing tax authorities with structured extracts of accounting data for audit purposes. Some countries, like Portugal and Luxembourg, require periodic SAF-T submissions. Others, like Belgium and France, are exploring whether real-time e-invoicing data can reduce or replace the need for separate SAF-T filings.
For a detailed look at SAF-T adoption across the continent, see our SAF-T adoption in Europe overview. If you work with Luxembourg’s SAF-T variant (FAIA), our FAIA Validator can help you check your files for compliance before submission.