Mandatory E-Invoicing in Belgium: What Businesses Need to Know
As of January 1, 2026, structured electronic invoicing has been mandatory for virtually all domestic transactions between Belgian VAT-registered businesses. With this, Belgium has taken a clear step away from invoices as documents toward invoices as structured data. A PDF sent via email is no longer considered a valid e-invoice for these transactions. Businesses must be able to send and receive invoices in a format that can be processed directly by accounting and ERP systems.
This requirement does not stand alone. It follows the earlier introduction of e-invoicing to Belgian government agencies and the European reforms under “VAT in the Digital Age,” better known as ViDA. Peppol serves as the primary infrastructure for secure data exchange in this context. Mercurius plays a specific role in invoicing the Belgian government.
What changes as a result of the Belgian requirement?
The Belgian requirement has been in effect since January 1, 2026, for virtually all goods and services exchanged between two Belgian VAT-registered businesses. Small businesses that utilize the VAT exemption scheme are also, in principle, subject to this requirement. Businesses that invoice exclusively to consumers are not required to send structured e-invoices for those outbound B2C invoices. However, they must generally be able to receive e-invoices from business suppliers.
There are limited exceptions. For example, VAT-registered entities not established in Belgium and without a permanent establishment are exempt from the Belgian B2B requirement. Exceptions also apply to certain exempt transactions, bankrupt companies, and a few specific categories of VAT-registered entities. However, the general rule remains simple: if a taxable transaction takes place between two Belgian VAT-registered businesses, a structured electronic invoice must, in principle, be used.
During the first three months of 2026, the FPS Finance applied a limited grace period for businesses that could demonstrate they had prepared in a timely and reasonable manner but nevertheless encountered technical difficulties. This was explicitly not a postponement of the statutory effective date.
What is a true e-invoice?
Not every digitally sent invoice is an e-invoice as defined by Belgian law. A PDF is digitally readable by humans but does not contain a fixed data structure that allows financial software to process all invoice data without additional recognition.
A structured e-invoice contains data such as the supplier, customer, invoice date, VAT, amounts, and payment information in separate, standardized fields. As a result, the receiving software can automatically read, verify, and forward this data to the financial accounting system. An invoice does not need to be manually retyped or interpreted by OCR software first.
In Belgium, Peppol BIS is the standard. This format complies with the European standard EN 16931 for electronic invoicing. Deviations are only permitted if both parties agree and the alternative format also complies with the European standard. In practice, using the standard simplifies the exchange, as there is no need to set up a separate integration for every customer or supplier.
What does ViDA have to do with Belgium?
ViDA stands for VAT in the Digital Age. With this package, the European Union is modernizing its VAT system. It includes, among other things, digital reporting based on e-invoicing, revised VAT rules for platform companies, and measures that reduce the need for businesses to register for VAT in multiple member states.
ViDA was adopted on March 11, 2025, and entered into force on April 14, 2025. From that point on, EU member states were given greater flexibility to introduce national e-invoicing requirements under certain conditions. The Belgian B2B requirement had already been enshrined in law, but it clearly fits within this same European trend.
The next major European step will take place on July 1, 2030. At that time, e-invoicing and digital reporting will become mandatory for relevant cross-border B2B transactions within the European Union. The current periodic reporting of intra-Community transactions will then be replaced by a much more direct digital flow of information. ViDA thus makes e-invoicing not only a means of exchanging documents, but also a foundation for VAT reporting and oversight.
The Role of Peppol
Peppol is an international network for the secure exchange of electronic business documents. The network does not require every company to establish a direct technical connection with every trading partner. Organizations connect via a certified Peppol Access Point Provider. Through that single access point, they can exchange documents with other connected organizations.
Peppol is the standard channel for the Belgian B2B requirement. Invoicing, accounting, or ERP software connects to the network via an Access Point. Peppol determines where an invoice must be delivered based on registered identification data. The Peppol BIS format then ensures that the sender and recipient use the same data structure.
Peppol extends beyond invoicing. The network also supports other transactional documents, such as credit memos, purchase orders, and order confirmations. As a result, a connection initially established for compliance purposes can later be used to digitize a larger portion of the commercial and financial supply chain.
The Role of Mercurius
Mercurius is the Belgian government’s central electronic mailroom for e-invoicing and e-procurement. The platform supports the receipt and routing of electronic invoices to Belgian government agencies. Suppliers send their invoices via Peppol, after which Mercurius ensures that they are delivered to the correct public entity.
The Mercurius portal also provides suppliers with insight into the receipt and processing of invoices they have sent to the public sector. This allows them to track the status of a government invoice in one place. The portal also provides a web form that allows authorized representatives to create and send an invoice to the government.
Mercurius and Peppol are therefore not competing solutions. Peppol is the network through which invoices are exchanged; Mercurius is the Belgian government service that receives, distributes, and provides visibility into invoices for public entities. Mercurius does not play a central role in standard B2B invoicing between businesses.
The Belgian Roadmap for E-Invoicing
Developments in Belgium and Europe can be summarized in four steps:
March 1, 2024: Structured e-invoicing became mandatory in Belgium for many new public procurement contracts. As a general rule, this applies to contracts valued at 3,000 euros or more, excluding VAT. For federal contracting authorities, the requirement may also apply below this threshold.
January 1, 2026: Structured e-invoicing became mandatory for virtually all domestic B2B transactions between Belgian VAT-registered businesses.
July 1, 2030: ViDA introduces mandatory e-invoicing and digital reporting for relevant cross-border B2B transactions within the EU.
January 1, 2035: Member States with older domestic systems for real-time digital reporting must bring them into line with the European model by this date at the latest.
What does this mean for organizations?
The transition requires more than just a Peppol registration. Organizations must verify whether their invoicing, accounting, and ERP systems can correctly create, receive, validate, and process structured invoices. Exceptions, credit memos, self-billing, international transactions, and archiving must also be factored into the setup.
Those who view e-invoicing solely as a legal obligation are only realizing part of its value. Structured invoice data enables automatic validation, matching, approval, posting, and follow-up. As a result, the Belgian requirement is not just a compliance issue, but also an opportunity to make the entire invoicing process faster, more controllable, and less manual.