Since 1 January 2026, businesses established in Belgium and registered for VAT must issue and receive structured electronic invoices for their domestic B2B transactions. The obligation comes from the law of 6 February 2024 amending the VAT Code. The default is a Peppol BIS Billing 3.0 invoice delivered over the Peppol network; another EN 16931-compliant format may be used only if both parties agree. A PDF sent by e-mail no longer counts as the legally required invoice for transactions in scope. Belgium plans a second step — near-real-time reporting of invoice data to the tax administration — from 2028, which has not yet been enacted.
Who is covered by the Belgian B2B mandate
The obligation applies when three conditions are met at once: the supplier is a VAT-taxable person established in Belgium, the customer is a taxable person who provides a Belgian VAT number, and the supply is located in Belgium for VAT purposes. The supplier must then issue a structured invoice and the customer must be able to receive one.
Two points from the FPS Finance FAQ surprise small businesses: the obligation also applies under the small-enterprise exemption scheme (turnover up to €25,000), at least for receiving; and a company that only sells to consumers still has to receive structured invoices from its suppliers.
The published exclusions, as of the review date:
- Persons who only carry out transactions exempt under Article 44 of the VAT Code;
- Taxable persons in bankruptcy;
- Taxable persons under the flat-rate scheme (abolished in 2028);
- Taxable persons not established in Belgium without a permanent establishment, even with a Belgian VAT number — the FAQ notes the law "is still being amended on this point";
- B2C transactions and, as a separate regime, invoices to public bodies (B2G, see below).
Whether a specific company or transaction is in scope — a foreign company with a Belgian branch, a partly exempt supply — requires professional confirmation. The B2B vs B2G page explains why the two regimes are separate.
Which format and network are required
The default is a Peppol BIS Billing 3.0 invoice (UBL syntax) exchanged over the Peppol network. Peppol BIS Billing 3.0 is a Core Invoice Usage Specification of EN 16931, so a Belgian structured invoice is by construction an EN 16931 invoice; Belgium decided that no additional national CIUS is necessary.
The law allows an opt-out: the parties may agree on another format that complies with EN 16931-1 and a syntax of CEN/TS 16931-2 (UBL or CII). The FPS FAQ states that structured invoices "should in theory be exchanged via the Peppol network" and that, where the counterparty is not ready, "there must be agreement on a secure alternative"; an invoice sent that way is legally valid. A customer cannot force suppliers into its own portal without their written consent.
| Element | Belgian rule since 1 January 2026 |
|---|---|
| Default format | Peppol BIS Billing 3.0, UBL 2.1 (invoice type 380, credit note 381) |
| Default transport | Peppol network via a Peppol service provider (access point) |
| Alternative | Another EN 16931-compliant format and secure channel, only by mutual agreement |
| Recipient identifier | Belgian enterprise number, Peppol scheme 0208; service providers must register it |
| Credit and debit notes | Same format and channel as the original structured invoice |
| Attachments | Must travel inside the UBL invoice (embedded or linked), not by separate e-mail |
| PDF copy | Optional; a recipient cannot demand one and cannot reject an invoice for lacking one |
The format is explained on the EN 16931 page, the network on Peppol and its addresses on Peppol identifiers.
Sanctions and the tolerance period
The existing VAT fines for missing or non-compliant invoices continue to apply. A new fine was added for not having the technical means to issue and receive structured invoices: €1,500 for a first offence, €3,000 for a second and €5,000 for each further one, a repeat counting only if established at least three months after the previous fine (Royal Decree of 8 July 2025 amending Royal Decree No 44).
FPS Finance granted a tolerance for the first three months of 2026 — no penalties for offences specific to the new obligation where the business could show timely and reasonable steps to comply, assessed case by case, expressly not a general postponement — and flexibility until 30 June 2026 for self-billing invoices. Both windows have closed as of the review date.
A customer that receives a non-structured invoice for a transaction in scope keeps, in principle, the right to deduct VAT under the substance-over-form doctrine, but may itself be fined for lacking the means to receive. A 2026 credit note correcting a 2025 PDF invoice has no format requirement; a credit note against a structured invoice must be structured too.
B2G before B2B: Mercurius and the public-procurement mandate
Under the law of 7 April 2019 transposing Directive 2014/55/EU and the Royal Decree of 9 March 2022, invoices to contracting authorities became mandatory in phases by contract value; since 1 March 2024 the obligation covers new public contracts of €3,000 or more (excluding VAT), and federal authorities apply it below that threshold. Flanders (2017), Brussels (2020) and Wallonia (2022) had regional mandates earlier.
Mercurius is the federal "mailroom" for the public sector: suppliers send Peppol invoices to any Belgian public body through it, without a bilateral connection, and can track processing; its portal also lets a supplier without software key in an invoice manually. FPS BOSA has been the Belgian Peppol Authority since 1 January 2016. Hermes, described in the European Commission factsheet, converts structured e-invoices into readable PDFs for recipients that cannot yet process them — a temporary bridge intended to be phased out.
What comes next: e-reporting from 2028 and ViDA
No invoice data is sent to the administration in the 2026 phase. The federal coalition agreement schedules near-real-time e-reporting of B2B invoice data for 2028, on the same Peppol infrastructure, to replace the annual customer listing. It has not been transposed into law, so start date, scope and mechanism remain open.
Cross-border reporting follows a different track: under the EU ViDA package (Directive (EU) 2025/516) Belgium will implement digital reporting for intra-Community transactions by 1 July 2030 at the latest — see the mandate timeline and cross-border e-invoicing.
How KRONENWERK handles Belgian e-invoicing
KRONENWERK generates a Peppol BIS Billing 3.0 UBL invoice for every invoice a Belgian company issues, validates it against the Peppol and EN 16931 Schematron rules at issuance, checks the buyer's VAT number against VIES and stores the tax verdict with the invoice. Incoming UBL invoices are read into bills. Document generation is SUPPORTED.
Transport is SUPPORTED WITH LIMITATIONS: KRONENWERK is not a Peppol access point. It sends and receives over Peppol through an accredited access point provider (Storecove) once the company is connected in Settings → Delivery; production sending depends on that account and its configuration. Until then the product shows the structured invoice as ready with a Peppol connection required, and never presents an e-mailed PDF as fulfilment of the obligation.
The procedure is on sending and receiving over Peppol; the country page Belgium lists product features and interface languages (NL and FR among them); a received file can be tested with the e-invoice checker. KRONENWERK does not file VAT returns or listings and does not give tax advice.
Frequently asked questions
Is a PDF invoice still legal in Belgium in 2026?
For domestic B2B transactions between Belgian VAT-registered businesses, no — the structured electronic invoice is the only legally required invoice. A PDF may be sent in addition. PDFs remain fine for consumers and for transactions outside the mandate.
Do I need to ask my customers for a Peppol ID?
No. Belgian service providers are contractually obliged to register every Belgian participant under its enterprise number (scheme 0208), so a supplier can address the enterprise number by default and check the Peppol Directory for readiness.
Does the mandate apply to foreign companies with a Belgian VAT number?
Not if they have no establishment in Belgium, according to the FPS FAQ, which adds that the law is still being amended on this point. A company with a Belgian branch should seek professional confirmation.
When does e-reporting start in Belgium?
The coalition agreement targets 2028 for near-real-time reporting of B2B invoice data; it has not yet been enacted, so the date is a plan, not law.
The pages in this guide
- What is Peppol? The e-invoicing network explained Peppol is an open network for exchanging e-invoices through accredited access points: four-corner model, SMP/SML lookup, BIS Billing 3.0, PINT and how to join.
- Peppol identifiers: scheme IDs, formats and how to look one up A Peppol ID is an ISO 6523 scheme code plus a value, e.g. 0208:0123456789. Common schemes (0208, 0204, 0088, 0106, 0192, 9925, 9930), rules and lookup.
- Sending and receiving Peppol invoices: a step-by-step guide How to send and receive e-invoices over Peppol: register with an access point, publish in the SMP, validate, read MLR and invoice responses, fix common errors.
Sources
- FPS BOSA / FPS Finance — einvoice.belgium.be, "Structured electronic invoices between companies are compulsory since 2026" — read on
- FPS BOSA / FPS Finance — FAQ, general questions on the B2B obligation — read on
- FPS BOSA / FPS Finance — FAQ, specific questions about e-invoicing (sanctions, credit notes, attachments) — read on
- FPS BOSA / FPS Finance — FAQ, general questions about e-reporting — read on
- FPS BOSA / FPS Finance — FAQ, general questions about Peppol — read on
- FPS Finance — Period of tolerance during the first three months of 2026 — read on
- FPS BOSA — E-invoicing to the government (B2G) — read on
- European Commission — eInvoicing in Belgium (country factsheet) — read on
- OpenPeppol — Country profile Belgium — read on