Sending a compliant e-invoice to a Belgian client, from outside Belgium

Since January 1, 2026, structured electronic invoicing is mandatory for B2B transactions between Belgian VAT-registered businesses, exchanged over the Peppol network (the transition tolerance ended March 31, 2026). Belgian companies have rebuilt their accounts-payable workflows around it.

Do I legally have to, as a foreign supplier?

Strictly: the Belgian mandate binds Belgian businesses, not you. Practically: your client's AP system now lives on Peppol. More and more Belgian companies ask suppliers — including foreign ones — to deliver invoices via Peppol, and a plain PDF gets processed slowly, bounced back, or asked to be re-submitted. The rejection email usually says something like "please send this as an e-invoice via Peppol".

What “compliant” actually means

Format: Peppol BIS Billing 3.0 — a UBL 2.1 XML document following the EN 16931 European semantic standard (specific required fields, VAT category codes, calculation rules).
Delivery: over the Peppol network to your client's participant ID — for Belgian companies usually their KBO/CBE enterprise number (scheme 0208).
Validation: the XML must pass the official schematron rules — “well-formed XML” is not enough.

Your options today

Ask the client to keep accepting PDF — works with small clients, increasingly refused by anyone with a finance team.
Belgian local apps — built for Belgian businesses: local-language UI, local onboarding, assume you are inside the ecosystem.
Enterprise e-invoicing networks — built for ERP volume, with pricing and onboarding to match.
A lightweight sender built for outsiders — that's what we're building: your invoice in, validated Peppol BIS out, delivered to your client's participant ID. From $19/month, no ERP.

Invoice Belgian clients from the US, UK, Australia, Asia?
Join early access — founding members lock in $99/year, forever.

FAQ

What is a Peppol participant ID? An address on the Peppol network. For Belgian companies it's typically their enterprise (KBO/CBE) number. If your client is registered, we can deliver to them.

What about VAT? A cross-border B2B service invoice into Belgium is usually reverse-charged (0% VAT with the right wording and codes on the invoice). The format still has to encode this correctly — that's part of what validation checks.

This page explains invoice formats and delivery, not tax rules. For VAT questions, talk to your accountant.