Belgium's B2B e-invoicing mandate is no longer something to plan for. It is in force. Since 1 January 2026, every VAT-registered business in Belgium must be able to send and receive structured electronic invoices for domestic B2B transactions.
If you are still emailing PDFs to Belgian customers, or wondering whether Peppol applies to your company, this guide answers the practical questions in plain language, without the ERP jargon.
This article is general compliance guidance, not legal advice. Rules can change; check with your accountant or the Belgian authorities for your specific situation.
Quick answer: is e-invoicing mandatory in Belgium?
Yes, for B2B. Since 1 January 2026, structured e-invoicing is mandatory for all domestic B2B invoices between VAT-registered Belgian businesses. The standard format is EN 16931, typically exchanged over the Peppol network as UBL-BE (Peppol BIS Billing 3.0).
Who must comply: Any Belgian business registered for VAT that invoices another Belgian VAT-registered business.
What changes in practice: You can no longer rely on unstructured PDF invoices alone for domestic B2B. Invoices must be structured, machine-readable, and delivered through an approved channel. Peppol is the dominant route in Belgium.
For the full country overview, see our Peppol Belgium page.
Belgium e-invoicing timeline
Belgium did not flip a switch overnight. The mandate built up in stages:
| Date | What changed |
|---|---|
| April 2019 | Federal government agencies must accept e-invoices via Peppol (B2G receive) |
| November 2022 | Suppliers to federal government must send e-invoices via Peppol (B2G send) |
| January 2026 | B2B mandate: structured e-invoicing required for all domestic B2B between VAT-registered businesses |
| 2028 (expected) | Broader EU digital reporting under ViDA (VAT in the Digital Age) |
If you already invoice Belgian public bodies, you may be partly set up. The B2B rule extends the same structured approach to all your domestic business customers and suppliers.
What is Peppol, and is it required?
Peppol (Pan-European Public Procurement On-Line) is the international network for exchanging structured business documents, especially e-invoices. Think of it as email for invoices: your software sends a structured file, the network routes it, and the recipient's system receives it automatically.
Belgium does not always say "you must use Peppol" in every sentence of the law, but in practice Peppol is the standard infrastructure for Belgian structured e-invoicing. The format (UBL-BE, aligned with EN 16931 and Peppol BIS Billing 3.0) is what trading partners and access points expect.
You do not need to understand XML. You need a tool that connects to a certified Peppol Access Point and handles formatting for you.
Peppol IDs in Belgium
Every business on the Peppol network has a participant identifier, a Peppol ID that works like an address.
In Belgium, this is typically based on your enterprise number (KBO/BCE):
- Scheme:
0208 - Example Peppol ID:
0208:0123456789(10-digit enterprise number) - VAT number:
BE0123456789(used for tax, related to your enterprise number)
Before you send an invoice, you need your customer's Peppol ID. You can look up whether a company is on the network with our free Peppol company search.
If you cannot find a buyer on Peppol, that is a common early problem, not a reason to skip compliance. Your customer may still be registering, or you may need the correct legal name or enterprise number. Searching by VAT number or official company name often helps.
What you must send and what you must receive
The mandate works both ways:
Sending (issuing invoices)
When you invoice a Belgian VAT-registered customer, you must issue a structured e-invoice in the required format, not only a PDF by email.
With Invoicier you create the invoice in the browser, and we convert and send it over Peppol. You can still send a PDF by email as a fallback when a buyer is not on the network, but the structured Peppol delivery is what satisfies the B2B requirement when the recipient is reachable.
Receiving (incoming invoices)
You must also be able to receive structured e-invoices from your suppliers. If you only send but never receive, you are only half-compliant.
Invoicier syncs incoming Peppol invoices into your dashboard automatically, so you can view, track, and manage supplier invoices without a separate portal.
Mercurius vs Peppol: what is the difference?
Mercurius is Belgium's government e-invoicing portal for public-sector (B2G) flows. If you invoice federal government entities, you may already know it.
Peppol is the broader network used for B2G and, since 2026, for B2B between businesses. Most Belgian SMEs will interact with Peppol daily for customer and supplier invoices, while Mercurius remains relevant for specific government workflows.
For a typical B2B SME, Peppol is the day-to-day channel that matters.
Do you need an ERP?
No. The mandate requires structured e-invoicing, not SAP, Odoo, or a six-month IT project.
Many Belgian freelancers, agencies, and small companies comply with a lightweight Peppol access tool:
- Sign up and add your Belgian company (KBO/BCE number)
- Get your Peppol ID registered on the network
- Send and receive invoices from one dashboard
That is exactly what Invoicier is built for: Peppol send and receive without ERP migration. If you later outgrow it, you can export or integrate, but you do not need an ERP to start.
How to get compliant with Invoicier (under 10 minutes)
- Create a free account. No credit card required.
- Add your Belgian company. Enter your enterprise number (KBO/BCE); we register your Peppol ID.
- Send your first invoice. Look up your customer's Peppol ID, create the invoice, and send.
- Receive automatically. Incoming supplier invoices appear in your Inbox.
The Free plan includes 2 invoices per month (sent + received combined). Paid plans raise the limit when your volume grows.
Common questions (FAQ)
Is Peppol mandatory in Belgium?
For practical B2B compliance in 2026, yes. Structured e-invoicing is mandatory, and Peppol is the standard way Belgian businesses exchange those invoices. If you operate in Flanders or Wallonia, the obligation is the same: domestic B2B between VAT-registered businesses.
Can I still send PDF invoices?
For domestic B2B between VAT-registered Belgian businesses, a PDF alone is not sufficient. You need a structured e-invoice. Some businesses also send a PDF copy for human readability, but the structured Peppol delivery is what counts for compliance.
What if my customer is not on Peppol?
Look them up first via Peppol company search. If they are not registered yet, they may still be onboarding. Belgium's mandate applies to them too. Invoicier also supports PDF email as a fallback for buyers who are not reachable on the network, but your own receive capability on Peppol should still be in place.
What format does Belgium use?
UBL-BE, compliant with Peppol BIS Billing 3.0 and the European semantic standard EN 16931. Invoicier generates and validates this automatically.
Does Peppol work for cross-border invoices?
Yes. Peppol operates in 50+ countries. A Belgian business can invoice Dutch, German, French, or other Peppol-connected customers on the same network. One Peppol ID, many countries.
What happens if I do not comply?
Non-compliant invoices may be rejected by recipients, which means delayed payments and extra admin chasing corrections. As reporting tightens under Belgian and EU digital VAT rules, the cost of staying on PDF-only workflows rises.
How much does compliance cost?
Invoicier starts free (2 transactions per month). Connecting to Peppol and sending your first structured invoice does not require an upfront subscription. See pricing when you need higher volume.
What to do this week
If you are a Belgian VAT-registered business and still invoicing B2B customers by PDF email:
- Confirm your customers' Peppol IDs (or look them up).
- Register your own Peppol ID if you have not already.
- Send a test invoice on the network before a large month-end batch.
- Turn on receiving so supplier invoices do not pile up in someone else's portal.
Belgium's mandate is live. The businesses that struggle are usually the ones who waited for "later", not the ones who needed an ERP.
Ready to connect? Start free with Invoicier and send your first Peppol invoice in minutes.