Belgium E-Invoicing Mandate: Six Months of Lessons Learned
Six months ago, on 1 January 2026, structured e-invoicing became mandatory for all VAT-registered businesses in Belgium. Now that the Belgium e-invoicing mandate lessons of the first half of 2026 are becoming clear, there is enough real-world experience to draw practical conclusions. At the Peppol Conference Europe 2026, held on 16 and 17 June in Brussels, this mid-year review featured prominently: a panel of Peppol experts and industry bodies discussed what went well, where businesses ran into trouble, and what comes next. This article summarises the key takeaways for Belgian and Dutch companies alike.
Why this review matters now
For companies that still need to start invoicing Belgian customers electronically, or that want to check their own implementation, this is the moment to learn from the first six months. Belgium is ahead of the curve in Europe with its broad Peppol-based B2B mandate, making it a practical case study for other member states preparing similar legislation, including France from September 2026 and the Netherlands over the medium term. Businesses already invoicing Belgian trading partners benefit directly from these lessons; those preparing their own mandate get a concrete picture of where the real friction lies.
The lessons in this article draw on public sources: official guidance from the Belgian authorities, legal analysis from advisory firms supporting businesses through implementation, and the panel discussion at the Peppol Conference Europe 2026 in Brussels, where representatives from the Peppol community and industry bodies shared the first practical experiences.
What changed on 1 January 2026
Since 1 January 2026, all VAT-registered businesses established in Belgium must exchange structured electronic invoices with each other for B2B transactions. Invoices must comply with the European semantic standard EN 16931, be sent in Peppol BIS format, and travel over the Peppol network under the familiar four-corner model. A PDF invoice sent by email is no longer sufficient: the invoice must be exchanged directly between both parties’ software via a Peppol Service Provider. The obligation for invoicing government bodies (B2G) had already applied since 1 March 2024. The legacy Hermes e-invoicing solution was decommissioned by 31 December 2025, following the recommendation of the Business Expert Group on e-invoicing.
The tolerance period: what was and wasn’t accepted
The Belgian authorities had announced a three-month tolerance period running from 1 January to 31 March 2026. During this window, the FPS Finance imposed no sanctions for infringements specifically tied to the new e-invoicing obligation, provided a business could demonstrate it had taken reasonable and timely steps towards compliance. That is an important nuance: the tolerance was conditional, not automatic. Businesses that had made no preparations at all could not simply rely on the grace period.
Common pitfalls in the first half of 2026
- Invoices not exchanged correctly via Peppol. An invoice not exchanged through the Peppol network is not considered valid. That has direct tax consequences: VAT on such an invoice can become non-deductible, with financial impact for both sender and receiver.
- Insufficient coordination between trading partners. When one party was unable to process a valid e-invoice, it created a legal and administrative problem for both sides. This affected smaller businesses in particular, which connected to a Peppol Service Provider late.
- Unclear mandatory data fields. Invoices must include, among other things, a correct invoice reference, VAT number, and bank details. Missing or incorrect fields led to processing errors on the receiving end.
- Late transition from PDF to structured e-invoicing. Some businesses kept sending PDF invoices after 1 January, assuming this would fall under the tolerance period. That is a risky assumption: tolerance only applied to businesses that could demonstrably show they were working towards compliance.
When fines actually start to apply
Since 1 April 2026, the tolerance period is over and standard sanctions apply for non-compliance. Fines are graduated: €1,500 for a first offence, €3,000 for a second, and €5,000 for a third offence within three months. For businesses that have not yet fully completed the transition to e-invoicing, this is a direct reason to check and, where necessary, fix their Peppol connection.
What’s next: from four-corner to five-corner e-reporting in 2028
The current mandate is not the end point. From 1 January 2028, Belgium will introduce a near real-time e-reporting obligation via a five-corner Peppol model, adding FPS Finance as the fifth corner of the network. Invoice data will then flow automatically to the tax authority at the moment of invoicing. Read more in our earlier news item on Belgium’s five-corner e-reporting from 2028. Peppol network governance is also changing: the role of national Peppol Authority moves from FPS BOSA to FPS Finance in 2027, a logical step given the network’s growing tax dimension.
What this means for Dutch companies invoicing Belgium
Dutch businesses supplying goods or services to VAT-registered Belgian customers face the same technical requirements as companies established in Belgium: invoices must be structured, comply with EN 16931, and be exchanged via Peppol. Companies already using a Peppol Service Provider for the Dutch market typically need little extra work: the main task is confirming that their provider also supports connection to the Belgian Peppol network and that invoice data meets Belgian requirements. Companies without a Peppol Service Provider yet should arrange this now, also with an eye on the Netherlands’ own upcoming e-invoicing developments.
How Belgium’s approach compares to other countries
Belgium is not the only country taking a major step this year, but the approach differs by member state. France introduces a phased mandate from September 2026, starting with a receiving obligation for structured invoices before the sending obligation follows, tied to certified Plateformes Agréées. The Netherlands has no legal B2B mandate yet; the government is working on a preferred direction aligned with the European ViDA timeline, with entry into force expected around 2030. Germany opted for a gradual rollout with a longer transition period for smaller businesses. What these countries have in common is a choice for Peppol, or Peppol-compatible infrastructure, as the technical foundation. For companies active in several of these markets, this means a single investment in a properly working Peppol connection pays off on multiple fronts, even though exact go-live dates and formats differ by country.
What small businesses and sole traders should watch for
The mandate in principle applies to all VAT-registered businesses in Belgium, including sole traders and small companies. In practice, the first six months showed this was often a bigger step for this group than for larger organisations with their own ERP systems and IT departments. Many accounting packages popular with sole traders and small businesses now have built-in Peppol connections, automatically formatting and sending invoices correctly without requiring users to understand the technical details. Even so, it is worth not blindly trusting default settings: check whether your accounting software has an actual active Peppol connection, rather than just generating a PDF export you still need to send yourself. For businesses invoicing only private consumers, the obligation does not apply to outgoing invoices, but as soon as B2B customers are added, compliance becomes mandatory from that point on.
How to check whether your Peppol connection actually works
A Peppol connection is not a one-time setup that then runs itself indefinitely. Experience from the past six months shows it pays to periodically verify that invoices actually arrive as intended. Ask your Peppol Service Provider for an overview of sent and received messages and check for any error notifications. Test the connection with a new trading partner before switching fully to electronic invoicing, so configuration issues surface before they turn into a dispute over invoice validity. Also establish who within your organisation is the first point of contact when an invoice fails to arrive, so this is not discovered only when preparing the VAT return.
Practical checklist for the second half of 2026
- Verify that your invoices are actually exchanged via the Peppol network, not just sent as a PDF.
- Check that invoice reference, VAT number, and bank details are correct and complete on every invoice.
- Confirm with your Belgian trading partners that they can receive and process e-invoices via Peppol.
- Ask your Peppol Service Provider about its roadmap for the 2028 five-corner e-reporting obligation.
- Assign internal ownership for monitoring changes in Belgian regulation, now that FPS Finance takes on a larger role.
Not sure your current setup is compliant, or not yet invoicing via Peppol? Compare certified Peppol Service Providers with support for the Belgian market and make an informed choice.
Conclusion: six months on, Belgium’s e-invoicing mandate is a learning process, not a finish line
The first six months of Belgium’s e-invoicing mandate show that the move to Peppol is technically achievable, but that practice is less forgiving than many businesses expected going in. An invoice not correctly exchanged via Peppol is simply not a valid invoice, with all the tax consequences that follow. Now that the tolerance period is over and fines are actually being applied, this is the moment to thoroughly check your own connection again, even if the first months went smoothly. With the 2028 five-corner e-reporting obligation already on the horizon, a robust Peppol implementation today is also an investment in the next phase of Belgium’s e-invoicing infrastructure.
- Loyens & Loeff: E-invoicing in Belgium as from 1 January 2026 — key provisions of the Royal Decree
- Tradeshift: Belgium B2B E-Invoicing Mandate 2026 — 3-Month Tolerance Period Explained
- Vertex: 2026 Belgium e-Invoicing Mandate Explained — Scope, Deadlines, and Penalties
- European Commission: eInvoicing in Belgium
- OpenPeppol: Peppol Conference Europe 2026, Brussels
