Here is the short version: since January 1, 2026, most businesses in Belgium must send and receive invoices as structured digital files, not plain PDFs. This is the new Belgium B2B e-invoicing mandate. It applies to companies and freelancers alike.
If you still email PDF invoices to your Belgian customers, this guide is for you. We will explain what changed in plain English. We will also show you how to set things up in just a few minutes. You will not need an expensive IT project.
This article is general compliance guidance, not legal advice. Rules can change, so always check with your accountant or the Belgian authorities for your specific situation.
Quick answer: is e-invoicing mandatory in Belgium?
Yes, for B2B. Since January 1, 2026, the rules are clear. If you are a Belgian business registered for VAT, and you invoice another Belgian business registered for VAT, you must use a structured e-invoice. A simple PDF is no longer enough.
In practice, this means three things:
- Sending a PDF by email is no longer acceptable on its own for domestic B2B sales.
- Your invoice must be a structured file. The official standard is EN 16931. People usually send these over the Peppol network in the UBL-BE format (also known as Peppol BIS Billing 3.0).
- You also need a way to receive these digital invoices from your own suppliers.
That is the whole mandate in a nutshell. We explain each part simply below.
For a full country overview, check out our Peppol Belgium page.
Are you a freelancer? Read this first
Most Belgian freelancers and one-person companies (eenmanszaak or indépendant) are surprised to learn that the mandate applies to them too. It does. If you are VAT-registered and you invoice other Belgian businesses, you are in scope.
The good news is that this change is much smaller than it sounds. You do not need complex accounting software, an ERP, or an IT consultant. Here is all it takes:
- You get a Peppol ID based on your enterprise number (KBO/BCE). This acts like a postal address for your invoices.
- You create your invoice in your web browser. The system then sends it out as a proper structured e-invoice.
- Invoices from your suppliers arrive in one simple inbox automatically.
Many freelancers send only a handful of invoices each month. Our free plan includes 2 invoices per month. This is often enough to stay compliant at zero cost. You can get set up in under 10 minutes, without changing how you work.
Belgium e-invoicing timeline
Belgium did not make this switch overnight. The rules arrived in careful steps:
| Date | What changed |
|---|---|
| April 2019 | Government agencies must accept e-invoices via Peppol (B2G receive). |
| November 2022 | Suppliers to the 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 might be partly set up. The B2B rule simply extends this same approach to all your Belgian business customers and suppliers.
What is Peppol, in plain words?
You can think of Peppol as email for invoices. Instead of attaching a PDF, your invoicing tool sends a structured file. The network delivers it, and your customer's computer system reads it automatically. There is no paper, and no manual typing is required.
The law does not actually say "you must use Peppol" in every single line. However, in the real world, Peppol is the standard way Belgian businesses exchange these invoices. The required format is UBL-BE. This format is based on EN 16931 and Peppol BIS Billing 3.0. It is exactly what everyone expects.
You do not need to understand XML or read technical formats. You just need a simple tool that connects to a certified Peppol Access Point. The tool handles all the technical details for you.
Your Peppol ID in Belgium
Every business on Peppol gets a Peppol ID. This works exactly like a home address, but for your invoices.
In Belgium, your ID is based on your enterprise number (KBO/BCE):
- Scheme:
0208 - Example Peppol ID:
0208:0123456789(your 10-digit enterprise number) - VAT number:
BE0123456789(used for tax, and linked directly to your enterprise number)
Before you send an invoice, you need to know your customer's Peppol ID. You can check if a company is on the network using our free Peppol company search.
Cannot find your customer on Peppol? That is very common right now. Please do not let this stop you from getting compliant. They might still be setting up their account. You might also need to search using their exact legal name or enterprise number. Searching by their VAT-registered number usually helps.
You must send AND receive
The mandate works both ways. This is the part people frequently miss.
Sending. When you invoice a Belgian VAT-registered customer, you must issue a structured e-invoice. A PDF by email is no longer enough. With Invoicier, you simply create the invoice in your browser, and we send it over Peppol. If a customer is not on the network yet, you can still send a PDF by email as a temporary backup.
Receiving. You also need a way to receive structured invoices from your suppliers. If you only send invoices and never receive them, you are only half compliant. Invoicier pulls incoming Peppol invoices into your dashboard automatically. Nothing gets stuck or lost in a separate portal.
Mercurius vs Peppol: what is the difference?
Mercurius is Belgium's government portal for public-sector invoicing (also known as B2G). If you invoice federal bodies, you probably know it already.
Peppol is the wider network. It is used for B2G, and since 2026, it is also used for B2B between regular businesses. For a typical business or freelancer, Peppol is the daily channel you will use. Mercurius stays relevant only for specific government flows.
Do you need an ERP? No.
This is the biggest myth out there. The mandate requires structured e-invoicing. It does not require SAP, Odoo, or a six-month IT project.
Most Belgian freelancers, agencies, and small companies get compliant with a lightweight Peppol tool:
- Sign up and add your Belgian company using your KBO/BCE number.
- Get your Peppol ID registered on the network.
- Send and receive invoices from one clean dashboard.
That is exactly what Invoicier is built to do. If your business grows later, you can export your data or integrate other tools. You simply do not need an ERP to start.
How to get compliant with Invoicier (under 10 minutes)
- Create a free account. You do not need a credit card.
- Add your Belgian company. Enter your enterprise number (KBO/BCE). We will register your Peppol ID.
- Send your first invoice. Look up your customer's Peppol ID, create the invoice, and click send.
- Receive automatically. Incoming supplier invoices will appear in your Inbox.
Our Free plan includes 2 invoices per month (sent and received combined). This covers many freelancers perfectly. Our paid plans raise the limit as your invoice volume grows.
Common questions (FAQ)
Does the mandate apply to freelancers and sole traders?
Yes. If you are VAT-registered and invoice other Belgian VAT-registered businesses, you are covered. This is true whether you are a large company or a one-person freelance business. The steps to comply are exactly the same. For most freelancers, our free plan is enough.
Is Peppol mandatory in Belgium?
For practical B2B compliance in 2026, yes. A structured e-invoice is required. Peppol is the standard way Belgian businesses exchange those invoices. Whether you are in Flanders or Wallonia, the rule is the same: domestic B2B between VAT-registered businesses requires it.
Can I still send PDF invoices?
For domestic B2B between VAT-registered Belgian businesses, a PDF alone is not enough. You need a structured e-invoice. You can still send a PDF copy for easy reading, but the structured Peppol delivery is what legally counts.
What if my customer is not on Peppol?
Look them up first with our Peppol company search. If they are not registered yet, they might still be onboarding. The mandate applies to them too. Invoicier also supports PDF email as a fallback for customers who are not reachable on the network. Meanwhile, your own receiving stays safely on Peppol.
What format does Belgium use?
Belgium uses UBL-BE. This format is fully compliant with Peppol BIS Billing 3.0 and the European standard EN 16931. Invoicier creates and validates this format for you automatically.
Does Peppol work for cross-border invoices?
Yes. Peppol runs in 50+ countries. A Belgian business can invoice Dutch, German, French, or other connected customers on the exact same network. You use one Peppol ID for many cross-border countries.
What happens if I do not comply?
Non-compliant invoices can be rejected by the recipient. This means delayed payment and extra admin work to fix the issue. As digital VAT reporting tightens across Belgium and the EU, staying on PDF-only gets more expensive and risky.
How much does it cost?
Invoicier starts free with 2 transactions per month. Connecting to Peppol and sending your first structured e-invoice does not require an upfront subscription. Check our pricing when you need more volume.
What to do this week
If you are a Belgian VAT-registered business or freelancer who still invoices by PDF email, take these steps:
- Register your own Peppol ID if you have not already.
- Look up your regular customers' Peppol IDs.
- Send a test invoice on the network before your next month-end billing batch.
- Turn on receiving so your supplier invoices do not pile up somewhere else.
The mandate is live right now. The businesses that struggle are usually the ones who kept waiting for "later", not the ones who needed an ERP.
Ready to connect? Start free with Invoicier and send your first Peppol invoice in minutes.