E-Invoicing in Belgium 2026: Mandatory B2B PEPPOL & EN 16931

Belgium made structured B2B e-invoicing mandatory from 1 January 2026: every VAT-registered business established in Belgium must send and receive PEPPOL BIS 3.0 invoices. B2G already runs over PEPPOL via the Mercurius platform. aiDoks validates and generates the right format — free.

Validate or Generate a PEPPOL Invoice PEPPOL BIS 3.0 Validator

Datos clave

Fechas de la obligaciónB2G ya obligatorio; B2B desde el 1 de enero de 2026.
A quién se aplicaToda empresa establecida en Bélgica y registrada a efectos de IVA.
Formato requeridoPEPPOL BIS 3.0 (EN 16931).
Red o portalLa red PEPPOL; Mercurius y Hermes para el sector público.

Belgian e-invoicing mandate timeline

B2G

B2G via Mercurius & PEPPOL

E-invoicing to Belgian public-sector buyers is mandatory and runs over the PEPPOL network through the federal Mercurius platform. Since 2024, structured e-invoices are required for public contracts; the Hermes service helps suppliers not yet connected to PEPPOL.

2026

1 January 2026 — B2B mandatory

From 1 January 2026, structured e-invoicing is mandatory for B2B transactions between taxable persons established in Belgium. Invoices must be issued and received as EN 16931-compliant structured documents over PEPPOL (BIS 3.0) by default. Paper and plain-PDF invoices no longer satisfy the obligation.

Next

Near-real-time reporting

Belgium plans to add e-reporting of transaction data to the tax authority, aligned with the EU VAT in the Digital Age (ViDA) reform expected from 2028–2030. Adopting PEPPOL now keeps you compliant and ready for the reporting phase.

Which format do you need?

PEPPOL BIS 3.0 (the Belgian default)

PEPPOL BIS Billing 3.0 (UBL 2.1, EN 16931) is the default format and network for the Belgian B2B mandate. You exchange invoices through a PEPPOL access point; both sending and receiving are mandatory. The same format works for cross-border EU invoicing.

EN 16931 (baseline norm)

The European e-invoicing standard underpinning the mandate. The law requires structured invoices in the European semantic standard; PEPPOL BIS 3.0 is a strict EN 16931 profile. aiDoks validates against the full EN 16931 rule set.

Mercurius (B2G channel)

Mercurius is the federal platform that routes e-invoices to Belgian public-sector buyers over PEPPOL. For B2G you connect through a PEPPOL access point or use Hermes if you are not yet on the network. The invoice content is the same EN 16931 structure.

Factur-X / cross-border formats

Trading with French or German partners? They may send Factur-X / ZUGFeRD (hybrid PDF) or XRechnung. aiDoks converts CII and Factur-X to PEPPOL UBL and back, so you can accept and re-issue invoices in whichever format each partner requires.

The 2026 B2B mandate — who is in scope

From 1 January 2026, the obligation applies to taxable persons (VAT-registered businesses) established in Belgium issuing invoices to other Belgian taxable persons. Both issuing and receiving structured e-invoices are mandatory, so even if you only receive invoices you must be able to accept PEPPOL. A few cases are excluded — for example certain VAT-exempt taxpayers and businesses in bankruptcy. To ease the transition, Belgium offers SMEs an increased tax deduction on e-invoicing software costs.

Mercurius, Hermes and the PEPPOL network

Belgium runs on PEPPOL. For B2G, the federal Mercurius platform receives invoices and routes them to public-sector buyers; the Hermes service can forward invoices to suppliers not yet connected to PEPPOL. For B2B, you simply need a PEPPOL access point (most accounting and ERP software now includes one). Each participant is identified by a PEPPOL participant ID — for Belgian companies usually the enterprise (KBO/BCE) number.

What is the Mercurius platform?

Mercurius is the Belgian government's e-invoicing "mailroom", operated by the federal public service BOSA. It receives every e-invoice sent to a Belgian public administration — federal, regional or local — over the PEPPOL network and routes it to the right buyer using the enterprise (KBO/BCE) number. Suppliers can follow the delivery and processing status of each invoice on the Mercurius web portal, which makes it easy to see whether an invoice was received, accepted or rejected. Mercurius only accepts structured EN 16931 invoices (PEPPOL BIS 3.0), so validating the XML before you send it is the fastest way to avoid a rejection.

How aiDoks helps Belgian businesses

Use aiDoks to validate any PEPPOL BIS 3.0 / EN 16931 invoice against the official schematron before you send it, so a buyer's access point never rejects it. Generate a compliant invoice from a simple form, or upload a PDF and let AI OCR extract the data into a structured invoice. And convert between PEPPOL UBL, CII and Factur-X when you trade with partners on other formats. aiDoks prepares and checks the file — your PEPPOL access point handles transmission.

E-invoicing in Belgium: FAQ

Is e-invoicing mandatory in Belgium?

Yes. From 1 January 2026, structured B2B e-invoicing is mandatory between VAT-registered businesses established in Belgium — both sending and receiving. B2G (invoices to public-sector buyers) has been mandatory and runs over PEPPOL via the Mercurius platform. The default format and network is PEPPOL BIS 3.0 (EN 16931).

When did the Belgian B2B mandate start?

1 January 2026. From that date, taxable persons established in Belgium must issue and receive structured e-invoices for domestic B2B transactions. The obligation was set by the Law of 6 February 2024.

What format does Belgium require?

PEPPOL BIS 3.0 (UBL 2.1, conforming to EN 16931), exchanged over the PEPPOL network, is the default. The law requires the European semantic standard EN 16931; an alternative network/format is permitted only if both parties agree and it meets the European standard. In practice almost everyone uses PEPPOL.

Who is in scope, and are there exemptions?

Taxable persons (VAT-registered businesses) established in Belgium, for invoices to other Belgian taxable persons. Both issuing and receiving are mandatory. Some cases are excluded — for example certain VAT-exempt taxpayers and businesses in bankruptcy. B2C invoices are not covered. Belgium also offers SMEs an increased tax deduction on e-invoicing software costs to help with the transition.

What are Mercurius and Hermes?

Mercurius is the Belgian federal platform that receives e-invoices and routes them to public-sector buyers over PEPPOL (B2G). Hermes is a service that forwards invoices to recipients not yet connected to PEPPOL. For B2B you generally just need a PEPPOL access point from your accounting or ERP provider.

How do I track the status of an invoice on the Mercurius platform?

Log in to the Mercurius web portal (operated by FPS BOSA) to see the delivery and processing status of every e-invoice you sent to a Belgian public administration — received, accepted or rejected. Invoices are matched by the enterprise (KBO/BCE) number. If an invoice is rejected, it usually failed EN 16931 / PEPPOL BIS 3.0 validation — validate the XML with aiDoks before sending to see the exact failing rule.

How does aiDoks help with Belgian e-invoicing?

aiDoks validates PEPPOL BIS 3.0 / EN 16931 invoices against the official schematron so they are accepted on the first try, generates compliant invoices from a guided form or an uploaded PDF (AI OCR), and converts between PEPPOL UBL, CII and Factur-X for cross-border partners. Free to start, no sign-up required to validate.

Related tools & guides

PEPPOL BIS 3.0 Validator

Validate UBL invoices against the EN 16931 and PEPPOL BIS 3.0 schematron rules.

Free E-Invoice Generator

Create a compliant PEPPOL BIS 3.0 invoice from a guided form, free.

E-Invoicing in France

Compare the neighbour's B2B mandate and Factur-X.

E-Invoicing in the Netherlands

NLCIUS and SI-UBL 2.0, and why the Dutch have no B2B mandate yet.

Ready to validate or generate Belgian e-invoices?

Free, accurate, PEPPOL BIS 3.0 and EN 16931 compliant.

Get Started Free Validate PEPPOL Invoice