The four-corner model
Peppol does not connect the sender directly to the recipient. Each connects to an accredited access point, and the two access points talk to each other under common rules. The sender transmits to their access point, which forwards to the recipient's access point, which delivers the invoice into their software.
The value of that model is that no business has to negotiate a connection with each of its partners. A single connection is enough to reach the whole network, whatever software sits on the other side.
The format and the directory
Invoices travel in Peppol BIS format, a profile of the European standard on electronic invoicing. Each participant is identified in a directory, in Belgium through their CBE enterprise number, which lets the sender know whether their customer is reachable on the network before sending.
That directory is also what makes the obligation verifiable: a registered business is deemed able to receive.
How to connect
In practice you do not connect to Peppol directly: you use invoicing or accounting software with a built-in access point, or a service acting as one. Most publishers active in Belgium have offered that connection since 2025.
Connection and configuration usually fall to the accounting firm or the software publisher. What stays with the client is more mundane but just as blocking: having clean customer data, starting with correct enterprise numbers.
What people often confuse
Peppol is a transport channel, not accounting software and not an archive. It delivers the invoice, it does not record it and it does not keep it for you. The ten-year retention requirement under article 60 of the VAT Code remains entirely yours, in a system you control.
Another common confusion: being connected is not enough if you can only receive. The Belgian obligation covers issuing and receiving.
The comparison of accounting software in Belgium reviews the main solutions and how to verify compatibility before committing.