Mandatory Peppol 2026 — Belgian SME B2B E-Invoicing Guide

In brief

Since 1 January 2026, all B2B invoices between VAT-registered entities in Belgium must be issued in the structured Peppol BIS 3.0 format (UBL XML) and transmitted via the Peppol network. Belgian SMEs must activate an access point, check their client portfolio coverage, and follow a 5-step switchover plan to avoid penalties.

The obligation, in plain words

Since 1 January 2026, all B2B invoices issued between VAT-registered entities in Belgium must be:

Structured in Peppol BIS 3.0 (UBL XML, not a PDF)

Transmitted through the Peppol network (not by email)

Retained in electronic form for 7 years

The obligation covers both sales and purchase invoices — issuing AND receiving. B2C remains free (PDF, email, paper). Cross-border transactions follow their own regime (Peppol encouraged, not mandated).

The SPF Finances published its operational framework in November 2025; a 6-month tolerance window applies for sanctions, but retroactive audits can cover the full year 2026.

Peppol in two minutes

Peppol is not a vendor — it's a network, like email. Three pieces:

You (the sender) are connected to a Peppol access point (your software or a service provider)

Your client (the receiver) is also connected to an access point

Both access points route the message via a shared directory (SMP)

Each Belgian company is identified by its BCE/KBO number in that directory. No need to swap emails, API keys or URLs — the invoice is delivered to the right recipient as soon as their BCE number is known and connected.

How to check whether a client is reachable

Before flipping 100 % Peppol, check the Peppol coverage of your client book. Company Belgium exposes a dedicated endpoint:

Terminal

# Check the Peppol status of a BCE number
curl https://companybelgium.be/api/v2/peppol/check \
  -H "X-API-Key: pk_live_..." \
  -H "X-API-Secret: sk_live_..." \
  -d '{"enterpriseNumber": "0200065765"}'

The response says whether the number is registered on the network, its access point, and the document types it accepts (invoice, credit note, purchase order). In batch you query 200 clients at a time to produce a connection report — green column = OK, red column = recontact with a templated memo explaining the obligation.

UBL format: what the invoice must contain

Peppol BIS 3.0 (UBL 2.1) requires at minimum:

Sender and recipient identifiers (BCE numbers)

Issue date and due date

Payment method, IBAN and structured communication (OGM-VCS)

Detailed lines with quantity, unit price, VAT rate, net and gross

Total net, total VAT per rate, total gross, any discount

Legal mentions: intracom reverse charge, article 44 exemption, etc.

Company Belgium's invoicing software validates every invoice against the Peppol schema before sending. As long as a mandatory mention is missing, the invoice stays in draft and the error is targeted (field highlighted). No silent rejects at the SMP side.

The trap: clients not yet connected

On 1 January 2026, around 60 % of Belgian SMEs are connected. What to do with the remaining 40 %? Three cases:

1. Client connected through another provider. You send in Peppol, their provider delivers — nothing for you to manage.

2. Client not connected but will be. You send in Peppol; the invoice queues on the SMP side and is delivered on connection. A courtesy PDF email is allowed until effective connection.

3. Client refusing to connect. The obligation lies on the sender: you must issue in Peppol format even if the recipient temporarily receives a courtesy PDF. The sanction concerns the issuance format, not the reception channel.

Our dashboard Invoicing → Peppol automatically sorts your client book into those three categories and offers a pre-drafted memo (FR/NL) for case 3.

5-step switchover plan

Map your portfolio — which clients are connected, which aren't

Enable your access point (Company Belgium defaults to Flowin, with Dokapi as fallback — configuration takes 10 min)

Issue a pilot invoice to a connected client to validate end-to-end

Communicate to non-connected clients a schedule and a memo

Switch over on the 1st of the following month — the old PDF channel stays active for documented exceptions

And the VAT return in all this?

Good news: with 100 % structured invoicing, the intracom listing (form 723) and the Intervat pre-calculation become trivial. Invoices are already split by rate, recipient, country. The Invoicing → VAT Declaration module aggregates everything automatically and exports the Intervat XML ready to upload to MyMinFin. That's what we shipped in May 2026 and it plugs naturally into Peppol. Go further with our complete guide to Peppol electronic invoicing in Belgium and our article on VAT in Belgium for businesses. Automated CODA bank reconciliation relies directly on Peppol invoices for matching. Also read our article on Peppol Dokapi sending and receiving electronic invoices for technical integration options.

Frequently asked questions

Is Peppol invoicing mandatory for all Belgian SMEs in 2026 ?

Yes, since 1 January 2026, all B2B invoices between VAT-registered entities in Belgium must be issued in Peppol BIS 3.0 (UBL XML) format and transmitted via the Peppol network. A 6-month tolerance window applies for administrative penalties, but audits can cover the entire year 2026. B2C transactions and cross-border exchanges are not subject to this obligation.

How do you check whether a Belgian client is registered on the Peppol network ?

Company Belgium provides a dedicated endpoint that queries the SMP directory in real time. By passing your client's BCE number, you get their status, access point, and accepted document types. In batch mode you can check up to 200 clients at once to generate a coverage report with green and red columns. This lets you prioritise follow-ups with clients not yet connected.

What to do if a client refuses to register on Peppol in Belgium ?

The obligation to issue in Peppol format lies with the sender, not the recipient. You must therefore issue the invoice in UBL XML format even if your client is not yet connected. You can send them a courtesy PDF in parallel until their effective connection. The penalty concerns the issuance format, not the client's reception method.

How long does it take to activate a Peppol access point for a Belgian SME ?

With Company Belgium, activating the Peppol access point takes around 10 minutes. The platform offers Flowin by default and Dokapi as a fallback option. You then send a pilot invoice to an already-connected client to validate the end-to-end circuit. The full switchover for all your B2B invoices can be completed in one working day.