That sounds technical, but its impact is wider than you might think. It not only affects your invoicing software, but also your bookkeeping, your VAT position and even your contractual agreements. Anyone who fails to comply is now also at risk of administrative fines of up to €5,000.
What is Peppol (and what is changing)?
Peppol is a secure network for sending e‑invoices directly from one accounting or invoicing system to another. It doesn’t work with “image files” (PDF), but structured files that can be automatically imported and processed. This is referred to as machine readability (whereas a PDF ensures human readability).
For your business, this means:
- less manual work and therefore fewer errors
- but also: the need to have the right software, accurate data and a tailored workflow.
Sending a PDF via email is no longer sufficient for B2B invoicing where the Peppol requirement applies.
Decide in 30 seconds: does this apply to your business?
Answer these three questions:
- Do you have a valid Belgian VAT number for the submission of periodic VAT returns? (yes/no)
- Do you send invoices to other Belgian businesses (B2B)? (yes/no)
- Do you qualify for a specific exemption? (yes/no) For example: exclusively exempt transactions (Art. 44), flat-rate scheme, bankruptcy, or not established in Belgium and having no permanent establishment in Belgium for VAT purposes
Yes to (1) + yes to (2) + no to (3): in this case you must be able to send and receive your B2B invoices in a structured format (in practice, this is usually done via Peppol, unless the supplier and customer mutually agree to opt out and a structured electronic invoice is still sent via another shared network). In any case, sending a PDF via email is no longer sufficient.
Yes to (1) + no to (2): you only invoice private individuals (B2C). In that case, you are not required to send your invoices to consumers via Peppol. As a VAT‑registered business you do have to be able to receive e‑invoices from suppliers.
'No' to (1): then the obligation usually does not apply to you in the same way (but it is best to check this, as the situation may vary depending on the activity and your status).
‘Yes' to (3): you will not be required to send electronic structured invoices, nor, in principle, to receive them. It is best to ask your accountant or advisor to confirm this.
Company registration number ≠ VAT number
In everyday language, the two are often used interchangeably, but they are used for different purposes.
In Peppol, a business is usually identified technically by its company registration number. There are also alternative so-called “Peppol identifiers”, such as a VAT number or GLN number (based on location, when invoices are issued from different branches). In Belgium, it is recommended to link to Peppol using the company registration number first and, where appropriate, to use the other “identifiers” as a secondary option (if that is useful in the specific business context).
The legal requirement to issue structured invoices incidentally depends on your VAT status and the type of transaction (B2B or B2C).
What about foreign customers and suppliers?
If you also do business with companies in other EU countries, you might expect to have to use structured electronic invoices for them too. However, this is not yet mandatory.
In cross‑border B2B relationships, where your customer has not yet voluntarily registered with Peppol, you are still allowed to issue invoices on paper or using standard digital formats, such as PDFs. This is partly because not all EU countries use Peppol: some use other platforms that are not always compatible. On the other hand, the obligation to issue e‑invoices is not being introduced everywhere at the same time. In some countries it is already in force, while others will follow later.
In an international context, businesses will therefore usually continue to rely on the invoicing methods that were being used before, unless the customer has voluntarily registered with Peppol.
What about receipts?
A VAT receipt, such as the one you receive in a restaurant, is a simplified invoice. It is a valid document and it does not have to be sent via Peppol.
If your business wants to claim back the VAT, a receipt like this is not sufficient. In such a situation you must request a full invoice, stating your company’s name and VAT number. You can only claim back the VAT if you have an invoice sent via Peppol.
What does this mean for your VAT deduction?
Peppol is not just a requirement for sending invoices. Your VAT deduction could also be queried during an audit.
In a B2B context, if you receive a PDF invoice or another unstructured invoice when invoicing via Peppol is mandatory, you are exposed to a genuine VAT risk. The VAT authorities could argue that the invoice is not in accordance with the rules and that this affects your right to claim a VAT deduction. In exceptional cases, it might still be argued that the economic reality is more important than the form of the invoice, but this is not automatic and it has to be demonstrated on a case-by-case basis. There is an exception to this rule if, as a customer, you are technically capable of receiving an electronic invoice, but it is only the supplier who is not Peppol-ready. In that case, the customer still retains their right to deduct VAT if the shortcoming is solely on the supplier’s side.
It is therefore also important as a buyer to be technically capable of receiving valid, structured Peppol invoices. To successfully defend your VAT deduction during an audit, it is not enough simply to have charged VAT correctly. The format of the invoice and the channel through which you receive it are important too. If you are not properly connected or if you consistently receive invoices outside the Peppol system when Peppol is mandatory, you will be at a disadvantage in the event of a VAT audit.
The fact that your business is not operating entirely in accordance with the Peppol rules does not automatically mean that you will forfeit your VAT deduction. However, if you are unable to receive and process Peppol invoices correctly, you are exposing yourself to an avoidable VAT risk.
In a nutshell: Using Peppol correctly is important not only for avoiding fines, but also for safeguarding your VAT deduction.
Does Peppol automatically make your invoicing terms binding?
No. This is a significant misunderstanding.
Sending an invoice via Peppol does not automatically make your invoice terms enforceable. The same is true in the online setting: terms and conditions must be provided to your customer in advance or, at the latest, when the contract is concluded, and your customer must accept them.
Good practice:
- include your terms and conditions in your quotation/contract (or clearly refer to them) and provide them before you start
- ask for a signature, the words ‘I agree’ via email, or confirmation via your customer portal
- restate on the invoice that these terms apply (but do not rely on this as the sole proof)
- keep the evidence (signed quotation, email, portal log, PDF containing the terms and conditions, etc.).
Switching to Peppol is a good opportunity to update your quotations, contracts and terms and conditions. Consider: what invoicing channel you use, what details you include, what to do in the event of a technical fault, and how you provide attachments (e.g. measurement reports) in a legally valid manner.
Practically, what do you have to do now?
In practical terms, for most businesses, only a small number of steps are needed:
· Check whether your invoicing or accounting software is able to send and receive invoices via Peppol
- update your customer and supplier records (correct numbers, names and addresses)
- talk to your accountant and software supplier about data reconciliation and workflow; and
- amend your quotations, contracts and terms and conditions where they contain provisions about invoicing or proof of payment.
In a nutshell: it’s not just IT. There is also an element of administration and contract management.
What if you're not ready yet?
For the first three months of 2026 there has been some temporary flexibility in practice to allow for teething problems. However, that period expired on 31 March 2026. It was not an official extension of the deadline.
Since 1 April 2026, you must therefore be able to actually send and receive structured e-invoices. If you are unable to do this, you are at risk of being fined: €1,500 for the first offence, €3,000 for the second offence and €5,000 for subsequent offences.
You can only be fined for a second or subsequent offence if at least three months have passed between the previous finding and a new inspection. In practice, this gives you some time to make adjustments, but you are still expected to get your system in order as soon as possible. In addition, the standard VAT penalties for missing or incorrect invoices remain in place.
Conclusion
Peppol is no longer just a technical detail. It has become the standard for B2B invoicing in Belgium. A PDF is no longer sufficient. Your software, your data and your contractual documents must all be aligned.
Are you unsure whether your business is handling mandatory invoicing via Peppol correctly? Or would you like to check whether your invoicing process, VAT status and contractual agreements are all aligned? Contact your Trusted Advisor at Grant Thornton. We can work with you to find a pragmatic, appropriate approach that suits your specific situation.
