What Is Peppol?
Peppol

If you have heard of Peppol, it was probably in connection with the UK's plan to make e-invoicing compulsory for VAT invoices from April 2029. Peppol is not a piece of software you buy, and it is not a government portal. It is a network, with shared rules and document formats, that lets any business send an invoice to any other business as data, whichever software each of them uses. In June 2026, the government announced that the UK's e-invoicing system will be built on it.

Where Peppol came from

Peppol stands for Pan-European Public Procurement On-Line. It started as an EU project to let suppliers send invoices and other procurement documents to public bodies in different countries. It is now governed by OpenPeppol AISBL, a non-profit international association established under Belgian law in 2012 and based in Brussels. Individual countries appoint Peppol Authorities to oversee the network locally; OpenPeppol lists NHS Supply Chain Coordination Ltd as the Peppol Authority for England, reflecting the NHS's early use of the network.

How Peppol works: the four-corner model

Peppol uses what is called a four-corner model:

The seller and the buyer each choose their own access point, and the two access points talk to each other using Peppol's common rules. That is the key difference from a closed network or a customer's supplier portal, where both sides have to use the same provider. OpenPeppol describes it simply: any organisation can send and receive business documents across the network through its chosen accredited service provider.

A fifth corner can be added, where invoice data is also shared with the tax authority. The UK government has said real-time reporting will not be introduced alongside the 2029 mandate.

How an invoice finds its way

Each business on Peppol has a participant identifier, typically based on an existing number such as a VAT number, with a code for the kind of number it is. When the seller's access point sends an invoice, it looks the buyer up in a central directory, the Service Metadata Locator (SML), which points to a Service Metadata Publisher (SMP) record. That record says which access point the buyer uses and which document types it can receive. The invoice is then sent securely between the two access points using a transport protocol called AS4. As a user, you never see any of this: your software handles it.

What travels over Peppol

Peppol carries documents in agreed formats called Business Interoperability Specifications, or BIS. For invoices, the main one is Peppol BIS Billing 3.0, which follows the European standard for e-invoices, EN 16931, and uses an XML format called UBL. The BIS Billing 3.0 guide explains it in more detail. Peppol also has formats for orders, credit notes, despatch advice and other documents, although invoicing is by far the most common use.

Whether the UK uses Peppol BIS Billing 3.0 as it stands, or a UK version of it, is one of the details still to be set out. The government's response to the consultation said it would review the risks and benefits of adopting an existing standard or designing a UK-specific one, and that its technical work would include possible extensions for sector-specific needs.

Peppol around the world

Peppol is used for e-invoicing in many countries, particularly in Europe and the Asia-Pacific region. The UK consultation response notes that a Peppol-based model is being implemented in many EU countries, as well as Singapore, Malaysia and Australia. Belgium, for example, made structured B2B e-invoicing compulsory between Belgian VAT-registered businesses from 1 January 2026, with Peppol as the default network. For UK businesses that trade internationally, a common network makes cross-border invoicing simpler.

Peppol in the UK today

Peppol is already used in parts of the UK public sector. NHS Supply Chain requires its suppliers to issue e-invoices through the Peppol network, and all bodies covered by the Public Procurement Act 2023 must accept e-invoices that comply with the European standard EN 16931. For most private businesses, though, Peppol has been optional and little used. In the 2025 consultation, a significant proportion of respondents called for alignment with international frameworks such as Peppol, and the government's June 2026 announcement confirmed that direction.

What Peppol means for a small business

For most sole traders and small companies, Peppol will be invisible. You will not connect to it directly or deal with XML. Instead, your accounting or invoicing software will either act as an access point or connect to one on your behalf. What you will notice is:

• Sending. Instead of emailing a PDF, you send the invoice from your software, and it arrives in your customer's accounts system.
• Receiving. Bills from suppliers arrive as data in your software, not attachments to retype.
• Customer details. You will need each business customer's Peppol identifier, which your software will usually look up.
• Choice. Because the network is open, you can change software without losing the ability to invoice your customers.

If you are not VAT registered, the mandate as announced applies to VAT invoices, and the government has said many of the smallest businesses that are not required to register for VAT and choose not to will not be obliged to adopt e-invoicing. The VAT registration checker shows where you stand.

Peppol compared with other ways of sending invoices

The consultation response describes businesses that use closed networks or portals as "locking their suppliers in" to particular providers. Peppol's open, four-corner design is what avoids that: one connection reaches every business on the network.

Benefits and limitations

The benefits the government and respondents describe come from invoices arriving as data. Invoices can be validated automatically before they are sent, so errors such as a missing VAT number are caught early. They post straight into the buyer's accounts, which speeds up approval and payment. And they leave a clear audit trail.

Security is part of the case too. The government's response notes that invoice fraud is a known problem for many businesses, and that e-invoicing can help by sharing invoices through secure systems and automating checks, for example flagging an invoice that asks for payment to a bank account not previously associated with that supplier.

The limitations are practical. You need software that connects to an access point, which may cost money. Both sides need to be on the network, which is exactly the problem the 2029 mandate is designed to solve. Some sectors send extra information alongside invoices, which the UK's technical work is expected to address through extensions. And until the roadmap is published, the UK-specific details are not known.

Peppol and the April 2029 mandate

The UK mandate guide tracks each announcement, and the Peppol explainer goes into more depth on how the UK is using it.

Getting ready

There is nothing you need to do on Peppol today, but a few steps make the switch easier later. Raise invoices in software rather than a word processor, so they already exist as data. Keep each customer's legal name, address and VAT number accurate, and use a consistent invoice number sequence. Ask your software provider whether it is, or plans to become, a Peppol access point. The preparation checklist for sole traders and the guide to choosing e-invoicing software walk through each step, and how to send an invoice covers the options you have now.

Common misunderstandings

• "Peppol is an HMRC system." It is an international network governed by OpenPeppol; HMRC does not run it.
• "I have to join Peppol." You connect through an access point, usually via your software.
• "Peppol means HMRC sees my invoices." The four-corner model exchanges invoices between businesses; no real-time reporting is planned for 2029.
• "Everything is decided." The network is announced; the detailed standards are not.

Related terms

Peppol is the network behind e-invoicing, reached through a Peppol access point. The invoices it carries hold the same legal content as any VAT invoice, and the e-invoicing hub brings every guide together.