Lessons from the Belgian e-invoicing frontline

The January 1 deadline was clear, but the "final mile" of implementation proved difficult for many. As highlighted in our article, E-Invoicing: Only one in three medium and large companies in Belgium is ready, e-invoicing readiness remains relatively low, with only 32% of medium and large firms capable of exchanging PEPPOL e-invoices by late 2025.

The latest survey results highlight this gap:

• Completed: Only 18% of organizations had fully finished implementation by the end of Q4 2025.
• In progress: Over three-quarters (77%) were still in the planning or execution phases just weeks before the mandate took effect.

For those organizations in the midst of the implementation process at the time of the survey, the level of progress varied, six out of ten had full implementation underway, while four out of ten were still finalizing their implementation.

Note: The Belgian government has introduced a three-month tolerance period (January–March 2026). During this window, no fines will be issued if a company can prove it has made "reasonable efforts" to comply.

Implementation was more than a simple "plug-and-play" update. The technical core of these projects often proved more complex than expected. Our survey revealed a significant difference in system readiness:

• Fully ready: Only 15% of respondents reported that their ERP, procurement, or accounting software fully supported e-invoicing out of the box.
• Required work: The vast majority (69%) had to perform partial adaptations or custom configurations to bridge the gap between their existing systems and modern e-invoicing tools.

Project management. This technical challenge also shaped how projects were managed internally. While the Finance department took sole responsibility in six out of ten cases, four out of ten organizations recognized the need for a cross-functional approach, involving not only Finance, but also IT and Procurement to manage the transition effectively.

The investment required for a successful implementation, including software, training, and system integration, varied significantly based on organizational complexity. While the average budget ranged between €50,000 and €60,000, the specific financial commitments tell a more nuanced story:

• Under €25,000: More than half of respondents managed the transition with a smaller budget.
• €100,000–€300,000: Only a small minority (15%) required these more substantial investments.

In six out of ten of cases, these funds were allocated to "essentials" like tool selection, PEPPOL setup, and basic training. Most firms (seven out of ten) relied on internal teams, though nearly a third engaged external consultants for technical guidance and integration support.

The data reveals that most companies allocate their budget primarily to essential requirements such as basic tool selection, set-up and training, relying on internal teams. Many companies treat e-invoicing as a mandatory "check-the-box" task rather than a strategic opportunity.

By focusing only on basic connectivity and internal execution, organizations often leave significant value on the table. True digital transformation goes beyond a technical connection. The real value of e-invoicing lies in capturing the business requirements, translating them into functional requirements, adapting processes, installing control:

• Process optimization: Capturing business requirements and translating them into streamlined workflows.
• Improved governance: Installing robust controls and clear data ownership.
• Strategic enablement: Aligning people, systems, and compliance to upgrade the entire financial function.

To make the investment worthwhile, organizations must look past the initial technical setup and use e-invoicing as an opportunity to upgrade their overall financial processes.

The data from our Q4 2025 survey confirms that the January 1st deadline was a milestone, not the finish line. Organizations now fall into two distinct categories, each requiring a specific strategic focus:

• Compliant organizations: For those that have reached full compliance, the focus must now shift to process optimization and risk mitigation. This involves refining workflows to eliminate errors and implementing audit controls to ensure long-term data integrity and the end-to-end invoice flow
• Transitioning Organizations: Those still finalizing their setup must treat this as a high-priority mandate. The three-month tolerance window is a grace period, not a deadline extension. To avoid penalties, firms must demonstrate significant progress immediately.

Moving forward, the shift toward mandatory e-invoicing should be viewed as a strategic opportunity rather than a mere regulatory hurdle. The companies who look beyond the initial burden of compliance will soon discover the real rewards: structured data can be a powerful engine for faster processing, a significant reduction in manual errors and vastly enhanced financial visibility. The mandate isn't just a legal requirement, it’s the foundation for a more efficient future.