Belgium’s 2026 E-Invoicing Mandate: The Tolerance Period Isn’t a Delay, It’s a Strategic Window

On 2 December 2025, Belgium’s Federal Public Service Finance confirmed two essential points:

1. The Belgian B2B e-invoicing mandate enters into force on 1 January 2026.

Structured electronic invoicing becomes mandatory for all domestic B2B transactions between VAT-liable companies.

2. A three-month tolerance period will apply during Q1 2026.

But this is not a postponement, the obligation remains fully active.The tolerance applies only to businesses that have genuinely begun their transition and are facing technical constraints.

Think of it not as a delay, but as a launch window: a short period where companies can finish their rollout without penalty risk.

This article explains what changes, what the tolerance really means, how enforcement will work, and how the right approach can turn these three months into a competitive advantage.

1. What changes on 1 January 2026

From this date onward, all Belgian VAT-liable companies must issue and receive structured electronic invoices for B2B domestic transactions.

Key elements:

• The mandatory format is EN 16931, typically in the Peppol BIS (UBL) profile.

• The default communication channel is Peppol. Alternative channels may only be used if both parties agree and remain technically able to communicate via Peppol.

• PDFs sent by e-mail are no longer considered electronic invoices in a legal sense.

2. What exactly is the tolerance period?

The SPF Finance grants tolerance for January - March 2026, but only for infractions directly linked to the e-invoicing mandate.

It applies only if a company can demonstrate good-faith effort, such as:

• transition initiated on time,

• solution provider selected or contracted,

• integration work or testing underway,

• system adjustments or mapping still in progress.

  
  

It does not apply to companies that simply waited.

The obligation itself remains fully active, the tolerance softens penalties, not compliance.

3. What happens after March 2026? Penalties increase quickly

The Royal Decree of 8 July 2025 introduced a specific penalty regime for companies that fail to provide the technical capability to send and receive compliant e-invoices via Peppol.

Typical amounts include:

• €1,500 for the first infringement

• €3,000 for the second

• €5,000 for each subsequent offence

  
  

Beyond administrative fines, the operational risks are even more severe:

• Customers may refuse non-compliant invoices,

• Payments may be delayed,

• VAT deductibility may be jeopardised,

• Many sectors will only accept Peppol-compliant invoices.

  
  

The message is clear: the tolerance period is a safety net, not a pause button.

4. Why the tolerance period is an opportunity, not an excuse to delay

Many companies may think, “We have until March.”In reality, Q1 2026 is the best moment to finalise implementation without enforcement pressure.

This window is ideal to:

• Finalise the technical setup

Select a Peppol provider, configure ERP or accounting integrations, validate mapping and numbering logic.

• Perform real-world testing

Send pilot invoices, validate reception, handle exceptions, test credit notes and cancellations.

• Clean and validate business data

VAT numbers, customer identifiers, Peppol participant data.

• Train internal teams

Finance, administration, IT, ERP owners, external accountants.

Everything done during this window reduces the risk of penalties later.

5. What qualifies as “good faith” for SPF Finance?

Although the SPF does not publish a strict checklist, their communication and legal commentary converge around the idea that a business acting in “good faith” is one that:

• has already initiated its transition before 1 January 2026;

• has selected or contracted a solution provider;

• can produce evidence of concrete actions (POs, agreements, tickets, workshops, test logs);

• is facing genuine technical difficulties, not organisational procrastination;

• is actively working to resolve remaining gaps.

  
  

In simple terms: If you can prove concrete steps, you are acting in good faith.

6. Where a provider like PeppolEDGE fits in this story

In this transition, a solution such as PeppolEDGE acts as a risk reducer and a speed-booster towards compliance.

Ultimate Flexibility

A solution like PeppolEDGE reduces risk, accelerates compliance, and provides the operational backbone needed during the transition.

Bridge for mapping & transformation

Companies keep generating invoices as they do today, ERP, CRM, legacy system, PDFs, CSVs, XML, JSON. The Bridge converts them automatically into compliant UBL BIS 3.0 for Peppol delivery, and performs the reverse transformation on incoming invoices.

Multi-environment deployment

Test, validation, and production run side-by-side. Subsidiaries, brands, or business units can onboard progressively without disrupting current workflows.

Monitoring & troubleshooting

The tolerance period is the ideal moment to catch issues:

• invalid VAT numbers

• delivery failures

• incorrect UBL structure or missing data

• customer mismatches

• sequence or logic errors

Fixing these now prevents fines, and operational chaos, later.

Hybrid workflows and Smart Forwarding

E-invoicing does not live in a vacuum. Many organisations still need to feed parallel systems such as accounting platforms, ERPs, BI tools, or document archives. With PeppolEDGE, structured e-invoicing does not prevent any of these workflows from continuing.

Thanks to Smart Forwarding, every outgoing or incoming invoice can be automatically duplicated, transformed or rerouted to secondary systems.

For example:

Sending the compliant Peppol UBL to the customer, while simultaneously delivering a CSV, XML or PDF copy to the accounting system, or forwarding structured data to another internal or external system.

Smart Forwarding and the Bridge Module allows hybrid setups where Peppol is the compliance backbone, but the organisation keeps full flexibility over how documents circulate internally.

Nothing is locked or constrained: Peppol goes where it must, and your operational workflows continue exactly as needed.

7. A quick readiness checklist for January–March 2026

1. Identify the invoices concerned

   Domestic B2B Belgium only, but for most companies, that’s a significant share of the yearly volume.

2. Validate customer data

   VAT numbers, registered names, addresses, Peppol IDs.

3. Select your technical solution

   ERP module, accounting software connector, or a dedicated platform like PeppolEDGE with its Flexibility.

4. Run pilot scenarios

   Start with a few customers early in January after using the test Environment.Validate sending, receiving, corrections and credit notes.

5. Document everything

   Contracts, project plans, screenshots, meeting minutes.It strengthens your evidence of good-faith transition.

8. Conclusion: The tolerance period is not a pause, it’s a launchpad

Here is the real takeaway:

• The Belgian e-invoicing mandate still enters into force on 1 January 2026.

• The SPF Finance offers tolerance only for companies that have genuinely started their transition.

• From April 2026, penalties become very real, plus the operational risks (rejected invoices, delayed payments, VAT issues).

  
  

Between now and then lies a three-month window that sends an implicit message:

“We won’t punish you while you finish the transition, but you must be in transition.”

This is precisely where PeppolEDGE shines:as the expert layer that absorbs the complexity, connects you to Peppol, monitors your flows, and gets you safely and confidently into the post-March landscape.