Since 1 January 2026, e-invoicing in Belgium is mandatory for all B2B transactions. This makes Belgium one of the first countries in Europe where structured e-invoicing is required across the entire business sector. If you send or receive invoices to or from Belgium, it is important to understand how this works.

Until 2024, e-invoicing in Belgium was voluntary. Since 1 March 2024, it is mandatory for invoicing government bodies (B2G) via the Mercurius platform. Since 1 January 2026, the obligation applies to all B2B transactions between Belgian enterprises. This means every invoice between two Belgian companies must be sent as a structured e-invoice. A PDF by email is no longer sufficient.

The Belgian government has chosen Peppol as the standard network for this exchange. The Peppol Authority in Belgium is BOSA. Invoices to government bodies are routed through Mercurius, the Belgian Peppol access point.

Not all enterprises fall under the B2B obligation. The following groups are (partially) exempt:

• No obligation to send for bankrupt VAT-liable entities, enterprises exclusively performing Art. 44-exempt transactions, non-Belgian established VAT-liable entities without a fixed establishment, and flat-rate VAT-liable entities. The exemption for flat-rate VAT-liable entities expires on 1 January 2028 at the latest.
• No obligation to receive for enterprises exclusively performing Art. 44-exempt transactions.
• For transactions that are fully exempt under Art. 44 of the VAT Code, there is no obligation to send or receive.

eConnect automatically routes invoices to Belgian organisations through the Peppol network to Mercurius. You don't need to configure anything extra: the platform recognises Belgian recipients and automatically selects the correct route.

Sending an invoice to Belgium works largely the same way as sending one to a Dutch recipient:

1. Create an invoice on platform.econnect.eu.
2. Look up the Belgian recipient using the enterprise number (10 digits, schemeID 0208) or the VAT number (format BE + 10 digits, schemeID 9925).
3. For reverse-charged VAT, make sure you use the correct VAT category code (K for intra-Community supply, AE for domestic reverse charge).
4. Optionally enter the structured reference (OGM) as payment reference.
5. Send the invoice. eConnect routes it automatically via Peppol.

Tip: when searching for a Belgian recipient, you can also search by company name. The platform searches both the Dutch KvK and the Belgian KBO database.

For Belgian customers, eConnect offers the free Invoice Portal, which allows you to start sending e-invoices via Peppol right away. eConnect also offers significant discounts for Belgian partners.

Belgian organisations are registered on Peppol with one of these identifier types:

The VAT number must follow the exact format BE followed by 10 digits, without spaces, dots or hyphens. For example: BE0123456789.

The Belgian Peppol implementation does not accept negative price lines. The total invoice amount may not be negative either. If you need to make a correction, do so using a separate credit note.

For intra-Community supplies (from the Netherlands to Belgium), the supplier does not charge VAT: the VAT is reverse-charged to the Belgian buyer. Make sure your invoice contains the correct VAT category code:

• K for intra-Community supply of goods (VAT reverse charge)
• AE for domestic reverse charge (e.g. subcontracting)

When invoicing Belgian companies with VAT reverse charge, eConnect automatically verifies the VAT number through the VIES system (VAT Information Exchange System). This confirms that the VAT number is valid and active.

Belgian invoices often include a structured reference (OGM): a payment reference in the format +++XXX/XXXX/XXXXX+++. This reference contains a built-in checksum and is automatically recognised and included in the e-invoice by the eConnect IDR.

You can also manually generate the Belgian payment reference when creating an invoice in the platform, using the "edit" option next to the payment reference.

In addition to the B2B e-invoicing obligation, Belgium is introducing a mandatory real-time fiscal e-Reporting system from 1 January 2028. This model is based on the Peppol 5-corner approach: Peppol Access Points report specific VAT data electronically to a central government platform. The approach is comparable to the 5-corner models in the UAE, Oman and Singapore.

For businesses that invoice through eConnect, this means that in addition to invoice exchange, tax reporting will also run through the Access Point. eConnect is following the technical specifications and preparing the reporting functionality as soon as the implementing rules are finalised.

Following the introduction of mandatory B2B e-invoicing on 1 January 2026, Belgium has seen various teething problems. Businesses report invoices not reaching the recipient, software issues with new service providers, and questions from accountants about the transition period. The number of Peppol service providers in Belgium grew to around 300 after the mandate.

The KVABB (Royal Association of Accountants and Tax Consultants of Belgium) requested a postponement for VAT return submissions in response to these issues.

The EY report on ViDA implementation in the Netherlands analyses these Belgian experiences and concludes that the problems are not caused by Peppol itself, but by the inexperience of service providers that have only recently become active. Experienced Peppol Service Providers, who have been active on the network for years, do not report comparable issues. The lesson: choose a service provider with proven experience in Peppol.

Want to start e-invoicing via Peppol as a Belgian company? Create a free account on the Invoice Portal.

• Peppol BIS Billing V3
• Belgian VAT and identifier formats
• Receipt confirmation from the Flemish government
• What is Peppol and how does the network work?
• VAT reverse charge: when to use code K or AE?
• EY report ViDA: the Netherlands heads towards mandatory e-invoicing