Mandatory e-invoicing via Peppol Starting in 2026: Preparing Technology, Processes, and People

Starting January 1, 2026, there will be a major change in the way Belgian companies handle their invoicing. From then on, all B2B invoices must be sent via the Peppol network are sent, in a standardized e-invoicing format.

For many organizations, this means a complete transformation: no more individual PDFs or paper invoices, but a fully digital, structured approach that is automatically processed by systems. This is more than just an IT upgrade; it’s a change that affects technology, processes, and people.

Those who plan ahead can turn this transition into an opportunity: streamlining processes, reducing errors, and improving collaboration between teams. Those who wait risk technical delays, higher costs, and resistance within the organization.

Technology: What Changes Will the Mandatory E-Invoicing via Peppol Bring?

To ensure the transition to structured e-invoicing, the government will introduce four key rules effective January 1, 2026. These go beyond simply ‘switching to a different file format’:

1. Mandatory Submission via Peppol
   All invoices between VAT-registered businesses must be sent via the Peppol network. PDFs or paper invoices are no longer legally valid for B2B transactions.
2. Standardized format
   Invoices must be prepared in the UBL (Universal Business Language) format, which allows systems to process them automatically without manual intervention.
3. Strict validation and verification
   Peppol performs automatic checks. Incomplete or incorrect invoices are rejected and do not reach the customer.
4. Fines for Noncompliance
   The government has established a tiered penalty structure: €1,500 for the first violation, €3,000 for a repeat offense, and €5,000 for ongoing noncompliance.

In short: e-invoicing via Peppol is not an optional choice, but a legal requirement that calls for timely technical preparation.

Processes: How Does Peppol Affect Your Day-to-Day Operations?

The transition to Peppol affects not only the technology, but also your billing processes and internal work agreements. For example:

• Revising the workflow from invoice creation to payment.
• Automating review and approval steps.
• Coordination between finance, IT, and other relevant departments.

Without adjusting processes, e-invoicing becomes an additional burden rather than a way to improve efficiency. Companies that review their processes early on often discover other areas for improvement—such as reducing duplicate entries or speeding up payments.

Your people are the key to a smooth adoption

Technology and processes are one side of the story. The other side? The people who have to work with it.

For finance, administrative, and IT staff, Peppol often means a new way of working. This includes using new software, stricter validation rules, and changes to controls. This can initially lead to resistance or result in errors.

Organizations that involve their employees from the very beginning have a clear advantage. Training, clear communication, and opportunities to ask questions are crucial. This ensures that Peppol is not seen as an imposed obligation, but as a tool that makes work easier.

Why It Pays to Start Now

January 1, 2026, may seem far off, but companies that wait until the last minute often run into:

• Delivery delays from software vendors.
• Internal decision-making issues.
• Unforeseen costs resulting from stopgap measures.

Starting early allows time to conduct phased testing, refine processes, and train employees. Those who start now will be able to continue working at a steady pace in early January instead of having to rush.

From Obligation to Opportunity

Mandatory e-invoicing via Peppol can be a source of stress, but it can also serve as a catalyst for modernization. By properly preparing your technology, processes, and people, you can turn this legal requirement into a strategic advantage.