E-invoicing via Peppol: getting your own software ready

Yes, since 1 January 2026 Belgian VAT-registered businesses have had to send each other structured electronic invoices over Peppol, and that applies just as much to anyone running their own software. The tolerance period ended on 31 March 2026, so if you still invoice from Word, Excel or an in-house system without a Peppol connection, you are risking fines. The good news for anyone on custom software: building that connection is a well defined, manageable project.

What exactly has been mandatory since 1 January 2026?

Every invoice between Belgian VAT-registered businesses has to be sent and received electronically in a structured format, as efactuur.belgium.be sets out. The standard is Peppol BIS, a UBL format that travels over the Peppol network. A PDF by email therefore does not count as an electronic invoice. A few points that are regularly explained wrong:

• Small businesses under the VAT exemption scheme (turnover up to €25,000) are covered too. Plenty of articles claim the opposite; the official page is perfectly clear about it.
• Agreeing on a different format is allowed (as long as it meets the European standard EN 16931), but you still have to be able to send and receive over Peppol.
• Invoices to consumers (B2C) fall outside the obligation, along with a few exceptions such as businesses whose activities are all VAT-exempt.

The Hermes fallback, which converted e-invoices into PDFs for companies that were not connected yet, was switched off on 31 December 2025. There is no detour left.

What fines do you risk without Peppol?

There are two separate penalties, and they get mixed up regularly. If you have no technical means to send or receive e-invoices, the fine runs from €1,500 for a first offence to €5,000 from the third one on. A non-compliant invoice costs you a further €25 to €250 each.

1. No technical means to send or receive e-invoices: €1,500 for a first offence, €3,000 for a second and €5,000 from the third on, with at least three months between two findings. No prior warning is required (Wolters Kluwer).
2. Non-compliant invoices (wrong or missing mandatory data): €25 to €250 per invoice depending on whether it is a first, second or later offence, with a ceiling that climbs from €500 to €5,000. That older fine can hit a badly drafted e-invoice as well.

The FPS Finance applied a tolerance period in the first quarter of 2026 for businesses that could show their preparations were under way. That period is over.

How do you connect your own software to Peppol?

Connecting directly to the Peppol network is not a realistic option for an SME, so the traffic runs through a certified access point. For custom software, a connection comes down to three pieces of work in practice: converting and sending outgoing invoices, processing incoming ones, and registering and checking your company.

1. Outgoing: your software converts every invoice into Peppol BIS (UBL) and sends it out through an access point's API.
2. Incoming: purchase invoices arrive through that same access point and flow straight into your administration or accounting package.
3. Registration and checks: your company is registered on the network and you use a service like Peppolcheck to confirm that everything is reachable.

Belgian access points with a decent API include Billit, Scrada, Flowin and Recommand. For an existing application with a tidy data model this usually takes a few weeks of work. If your invoicing still lives in Excel, the Peppol obligation is a good reason to digitise that process properly in one go, often as part of a wider track around custom internal tools.

Is there tax relief for the switch?

Partly, yes. Small SMEs and self-employed people who work with subscription-based tools may deduct 120% of the cost of invoicing software, a temporary measure that runs from 2024 through 2027. On top of that, an increased investment deduction of 20% for digital investments has applied since 1 January 2025.

Building a custom connection does not automatically qualify, so check with your accountant before you count on it. If you want to know which other channels exist for software, the kmo-portefeuille, the Flemish subsidy scheme for SMEs, is worth a look.

What is coming on top in 2028?

From 2028 Belgium intends to introduce near real-time e-reporting: invoice data would then flow to the tax authorities almost immediately through a five-corner model on Peppol, replacing the annual client listing. For now this lives only in the coalition agreement and the official FAQ; it has not been written into Belgian law yet.

If you are building a connection today, make sure your invoice data is clean and structured. Then 2028 becomes an update instead of a second project.

How far along is the rest of Belgium?

In early March 2026 roughly 83% of Belgian businesses were on Peppol, close to a million companies (OECCBB). Anyone still not connected sits in the final 17%. On top of that, since 1 January 2026 customers have had the right to refuse invoices that do not arrive over Peppol.

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Does your invoicing run in your own software, or somewhere between Excel and an ageing package? Tell us how you invoice today and you will get an honest picture of what a Peppol connection costs and how long it takes. If it does not fit in those few weeks, we will say so too.