FAQs on Belgian e-invoicing requirements updated

On 7 October 2025, Belgium’s Federal Public Service Policy and Support (FPS BOSA) published an updated version of the frequently asked questions (FAQs) on the official FAQ page regarding the existing business-to-government (B2G) and upcoming business-to-business (B2B) electronic invoicing (“e-invoicing”) mandate. 

This update follows a series of constructive exchanges with the tax authorities, highlighting the impact of continued dialogue between stakeholders and policymakers. This alert provides an overview of the most important modifications included in the latest version of the FAQs and related developments concerning a potential transitional regime for e-invoicing and the discontinuation of the Hermes portal. 

Invoice date determines e-invoicing applicability

As from 1 January 2026, all invoices subject to the Belgian e-invoicing mandate must be issued in a structured electronic format. The tax authorities have confirmed that the obligation applies to any invoice that is issued, delivered, or transmitted on or after that date, regardless of when the underlying transaction took place, as stated in article 53, § 2bis of the Belgian VAT Code. Consequently, it will be the date of issuance of the invoice—not the date of the underlying taxable transaction—that determines whether an invoice must be issued in a structured electronic format as from 1 January 2026. 

Credit notes related to invoices issued in 2025

It has already been clarified that any document that modifies and explicitly refers to an original structured electronic invoice (“e-invoice”) must be issued in the same structured format. This principle applies to credit notes, which are required to follow the format of the original invoice they amend.  

The Belgian tax authorities have now confirmed that if the original invoice was not structured—such as a PDF—then no specific format is required for the corresponding credit note. Consequently, credit notes may still be issued as PDFs from 2026 onwards, but only with the recipient’s consent. 

If the supplier opts to issue the credit note in a structured electronic format—which will in principle be mandatory as from 1 January 2026—the recipient is obliged to accept it.  

Impact on VAT deduction right

The Belgian tax authorities have clarified that to exercise the right to deduct VAT on incoming invoices, recipients must possess a valid B2B invoice, as provided for in article 3, § 1, 1° of Royal Decree No. 3. For transactions falling under the Belgian e-invoicing mandate, this means that, in principle, only a structured e-invoice qualifies as acceptable documentation for VAT deduction purposes. 

Nonetheless, as stated by the tax authorities, jurisprudence from the Court of Justice of the European Union (CJEU) has consistently underscored the primacy of VAT neutrality. According to the CJEU, input VAT must be deductible when the substantive conditions are met—even if certain formalities, such as holding a compliant invoice—are not strictly fulfilled. This interpretation prioritises the economic substance of a transaction over strict formalities. 

Consequently, the risk of VAT deduction being denied solely due to the use of unstructured invoices (e.g., paper or PDF) after 2026 remains largely theoretical. That said, future developments—particularly under the VAT in the Digital Age (ViDA) initiative—may alter this position. Under ViDA, possession of a valid e-invoice could become a substantive condition for reclaiming or deducting VAT, although such changes are not anticipated before 2030. 

Transitional regime

According to an article published in De Tijd on 8 October 2025, the Belgian tax authorities are exploring the possibility of a transitional regime for companies that have made sincere efforts to comply with the upcoming e-invoicing mandate but have faced implementation challenges. 

Importantly, this should not be interpreted as a general postponement of the 1 January 2026 deadline. Rather, businesses that meet specific conditions and can demonstrate genuine attempts to prepare may be granted relief from penalties. 

At present, it remains unclear which types of challenges will be considered acceptable, and what evidence companies will need to provide to show timely initiation of e-invoicing implementation. The tax authorities are actively working on further guidance to clarify these criteria. 

Discontinuation of Hermes 

The Hermes platform, an official tool of the Belgian authorities that offers a solution for sending structured e-invoices, will be discontinued as of 31 December 2025. After this date, it will no longer be possible to send or receive documents via Hermes. 

Organisations currently using Hermes are advised to switch to another service provider before the end-of-life date. Their Peppol service provider or access point will handle the migration from Hermes to the alternative system selected.