Nine months have passed since 1 January 2026, when PEPPOL electronic invoicing became mandatory for all B2B transactions in Belgium. Where do we stand today, what are businesses still struggling with, and — most importantly — what is coming between now and 2028?
This article is a concrete review of the situation in September 2026, no marketing, based on what we actually see day-to-day in PEPPOL flows across DEMFACT.
PEPPOL adoption in Belgium: where do we really stand?
Most Belgian companies have made the transition, but real-world adoption is very uneven depending on size and sector:
- Large companies and public administrations: fully operational for a long time (B2G was already mandatory since 2019). They send and receive thousands of PEPPOL invoices daily.
- Accountants and audit firms: most have adapted their tools, but certain professional software packages are lagging behind and force workarounds.
- SMEs and self-employed: this is where the situation is most uneven. Many adopted a simple platform (like DEMFACT), others still send PDFs by email hoping their clients accept them, which is no longer compliant for B2B.
- Non-profits and micro-businesses: the delay here is most visible. Many still do not know the rule also applies to them the moment they invoice other VAT-registered businesses.
The essential legal reminder
Since 1 January 2026, a PDF invoice sent by email is no longer considered a compliant electronic invoice for B2B transactions in Belgium. The invoice must go through the PEPPOL network in UBL 2.1 (BIS 3.0) format, even if the recipient is your neighbour.
The most common issues in 2026
1. "My invoice stays in 'pending' for hours"
By far the most-asked question. Reassuringly, this is normal in these cases:
- First delivery to a new client: the PEPPOL network must first discover the access point where your recipient is registered, via a mechanism called SMP discovery. This discovery can take 1 to 4 hours the first time. Subsequent deliveries to the same client then take 10 minutes.
- Recipient's access point is overloaded: some providers have queues during peak activity (month-end, VAT quarter-end).
If your invoice stays stuck for more than 24 hours, contact your sending platform.
2. "The client's VAT number is valid but the invoice is rejected"
A valid VAT number does not mean the company is registered on PEPPOL. Since January 2026, all Belgian VAT-registered companies must be able to receive PEPPOL invoices, but in practice some have still not activated their receive endpoint. Two checks to run:
- Check the recipient in the Peppol Directory (public search engine).
- If absent, the only option is to send a PDF by email, clearly telling the client they must register on PEPPOL before their next invoice.
3. "I sent the invoice twice by mistake"
It happens more often than you would think: a button that responds slowly, a double-click, and the same invoice is sent twice. On DEMFACT we recently introduced a protection against double-sends: the second click within 60 seconds is refused automatically. Most modern ERP systems that receive an invoice with a duplicate number mark it as a duplicate, so the accounting risk is low, but always inform your client by email if it happens.
4. "Malformed structured communication"
The Belgian structured communication (+++XXX/XXXX/XXXXX+++) must be correctly calculated with the modulo 97 check digit. A calculation error is the most common cause of bank reconciliation failure on the client side. Check that your software calculates this automatically — a good sign is that it already shows on the draft.
What has changed technically
Peppol BIS 3.0 and PINT
The European standard is evolving toward Peppol International Invoice (PINT), an additional layer on top of BIS 3.0 aimed at harmonising exchanges beyond Europe. For Belgium, no action is required in 2026, but software will have to support PINT progressively during 2027.
CIUS_BE updates
The Belgian profile CIUS_BE (Core Invoice Usage Specification) was updated in June 2026 to clarify several ambiguous points, notably handling of the 6% VAT rate in construction (Cocontractant) and self-billing invoices. A good PEPPOL provider should have updated their UBL engine accordingly.
Improved receive for micro-businesses
Since April 2026, Belgium requires that every VAT-registered business has an active PEPPOL receive endpoint, regardless of turnover. This also concerns micro-businesses exempt from VAT (below 25,000 EUR) that receive invoices from other VAT-registered parties.
What is coming by 2028: e-Reporting
The next major wave is e-Reporting, planned for 2028. It is no longer just about sending the invoice to the client via PEPPOL — but also about transmitting billing data in real time to the SPF Finances (Belgian tax administration).
In concrete terms:
- Every invoice issued or received will automatically generate a declaration to the administration.
- The periodic VAT return (monthly or quarterly) will be pre-filled based on this data.
- Tax control will become continuous instead of annual: fewer surprises, but also less margin for error.
To prepare, the best step already is to have a PEPPOL software that cleanly handles all your invoicing flows (send and receive), with archiving compliant with the Belgian 7-year retention law. That will be the technical basis of 2028 e-Reporting.
Our practical tips for September 2026
- Check that your platform sends AND receives via PEPPOL. Many users only have send enabled without knowing — this was acceptable until April, no longer.
- Test your first send to a new client in advance, not at the last minute (because of the 1 to 4 hour discovery).
- Always use structured communication on your invoices: this lets the client auto-reconcile the payment, and gets you paid faster.
- Never delete a PEPPOL invoice already sent. If you made a mistake, issue a credit note that explicitly references the incorrect invoice.
- Archive your original UBL files for 7 years. Belgian law requires it. A good software does this automatically — check.
Summary
Nine months after the mandatory transition, PEPPOL in Belgium is working but still bedding in. Large companies are comfortable, most SMEs have made the switch, but a significant number of non-profits, micro-businesses and self-employed remain behind — sometimes from lack of awareness, sometimes from lack of a suitable tool.
The next major milestone is e-Reporting in 2028. That is not a reason to wait: businesses already using PEPPOL day-to-day will adapt naturally. Those who have not yet made the switch will have everything to learn at once.
If you are not yet set up, a tool like DEMFACT lets you send your first PEPPOL invoice in minutes, without a fixed subscription (from 2 EUR per invoice). One sign-up, Belgian VAT, PEPPOL active, VAT calculated automatically, structured communication generated.
Questions about your specific PEPPOL situation? Contact us at support@demfact.com or test the DemBot assistant directly in the app.