E-invoicing in Belgium: be compliant without changing how you work

What changed on 1 January 2026

B2B invoices between VAT-registered businesses established in Belgium must now be issued in a structured electronic format — the European EN 16931 standard, as Peppol BIS 3.0 — and travel over the Peppol network.

In practice: a PDF attached to an e-mail is no longer a compliant invoice between businesses. The invoice must be a structured, machine-readable file sent through a Peppol access point.

Who is affected?

The mandate covers invoices between VAT-registered businesses established in Belgium: freelancers, liberal professions, small businesses and SMEs — from the very first B2B invoice.

• You invoice other Belgian businesses → you are affected
• You invoice consumers (B2C) → no structured-invoice obligation
• You invoice foreign clients → different regime, the Belgian mandate does not require a structured invoice

Some special regimes have exceptions or specific rules. If in doubt about your situation, check with your accountant.

How KROLYX makes you compliant

You create your invoice as usual — client, lines, VAT. KROLYX handles the rest:

• Issued in the structured Peppol BIS 3.0 format (EN 16931 standard)
• Transmitted over the Peppol network
• Legal sequential numbering and mandatory mentions
• Payment tracking and automatic reminders

How Peppol works, without the jargon

Peppol works like a digital postal network between software systems. Each business is registered on the network through its company number, and invoices travel from one "access point" to another — from the sender's software to the recipient's — without ever going through e-mail.

An access point is a certified operator acting as a post office: it validates the invoice format, locates the recipient on the network and delivers the invoice with a delivery receipt. KROLYX is connected to a certified access point: when you click "Send", the invoice goes out on the network and you track its status (sent, delivered, failed) right inside the app.

The result: no more invoices lost in spam, no more "I never received it" — every delivery leaves a timestamped trace.

What do you risk if you're not compliant?

A B2B invoice that doesn't follow the mandated format is not a compliant invoice. In practice this exposes you to several risks: your client can reject the invoice (delaying payment), the client's VAT deduction can be challenged, and administrative fines apply for repeated breaches.

Beyond sanctions, the most immediate risk is commercial: your business clients — and their accountants — now expect invoices that land directly in their software. The supplier still e-mailing PDFs creates manual work for their client, and becomes the one who gets paid last.

Classic PDF vs structured invoice: what's the difference?

A PDF is a picture of an invoice: a human can read it, but accounting software has to re-type it (or OCR it, with errors). A structured invoice is a data file: every amount, VAT rate, reference and due date is a field the recipient's software reads instantly and without errors.

That's what makes the mandate useful beyond compliance: automatic booking on your client's side, fewer disputes, faster payments. In KROLYX you never see the complexity: you create your invoice normally, and the structured file (UBL, Peppol BIS 3.0 profile) is generated and transmitted automatically — with an optional courtesy PDF for human reading.

Migrate in 4 steps, with no interruption

Switching to e-invoicing with KROLYX takes an afternoon, without interrupting your ongoing invoicing:

• 1. Import your clients (CSV, Excel or copy-paste) — their company numbers are enough to identify them on Peppol
• 2. Complete your issuer details: company number, VAT status, bank details
• 3. Create your first invoice as usual — KROLYX generates the structured format and transmits it via Peppol
• 4. Track delivery statuses and let automatic reminders do the rest

Your past invoices stay available: import them to keep your full history in one place.

The tax bonus: the increased deduction

To support the transition, Belgium provides an increased 120% tax deduction on e-invoicing software subscription costs for self-employed workers and small companies, for tax years 2024 to 2027. Your KROLYX subscription may therefore cost you less after tax than its sticker price — confirm the conditions with your accountant.

Also invoicing into France?

France is on the same path: from 1 September 2026, every VAT-registered business must be able to receive electronic invoices, and the obligation to issue extends to small and micro businesses on 1 September 2027. KROLYX is in the process of registering as an accredited platform — see our Compliance page for the dated status.