Mercurius: the electronic mail room for our public entities

Mercurius: the electronic mail room for our public entities

Mercurius receives invoices sent to Belgian public entities and passes them on to their recipients.

In other words, this platform ensures that electronic invoices are duly sent between the system used by the sender of the invoice and that used by its recipient.  Like any mail room, it facilitates the routing of documents between correspondents.

It is accompanied by a web portal to which persons representing public entities, their suppliers and IT operators can connect and monitor the routing and processing of invoices.

A solution based on the Peppol standard

The “electronic postal system” that connects the senders of invoices to this centralised mail room of the Belgian public authorities, works thanks to collaboration between the operators of the various e-invoicing platforms, based on the standardised PEPPOL framework.

Mercurius is responsible for forwarding all electronic invoices that comply with the standardised Peppol framework. Thanks to Mercurius (and Peppol), each sender is therefore free to choose the operator that is the best fit for them, knowing that all Belgian public authorities will receive its invoices

Not only invoices

Like any mail room, Mercurius doesn’t just route invoices to public authorities: 

  • Invoice approvals (or rejections) by public authorities result in the issuance of response documents. The entities concerned forward these responses to Mercurius, which in turn routes them to the suppliers concerned.

  • Public authorities also issue invoices to companies.

  • This is referred to as outgoing invoicing. The entities concerned forward these invoices to Mercurius, which routes them to the recipient.

  • Purchase orders generally precede incoming invoices. These are also gradually being replaced by structured electronic documents. Entities able to produce their purchase orders in this format can forward them to Mercurius, which routes them to their final recipient.

The fact that these documents are routed on its behalf, relieves the entity of all kinds of practical difficulties related to this aspect, and therefore helps it considerably in its efforts to go paperless. The Mercurius platform therefore plays a key role in the success of projects rolled out by public service entities.

What is the Mercurius portal used for?

The Mercurius platform is supplemented by a portal on which suppliers can:

  • consult the list of invoices they have sent to Belgian public entities;


  • manually issue invoices or credit notes. This feature is useful if the supplier's invoicing software is not yet adapted to the standardised PEPPOL framework.

As for the public entities, they use it to consult the list of invoices sent by their suppliers. This allows them to deal more effectively with their questions.

Finally the IT operators (service providers, customer back-end teams, etc.) can track all flows related to their services This is a big boost to the traceability and transparency of exchanges, which is in the interests of operators and their customers.

How do I send my invoice to the public authorities?

Peppol and Mercurius aim to facilitate the transition to electronic invoicing. If your invoicing software is able to issue an electronic invoice that complies with the Peppol framework (and therefore with the European Standard), all you have to do is use this software. This is already the case for many software programs. 

If this is not the case, you can manually send your invoice on the Mercurius portal.

How can I log onto the Mercurius portal?

  • The legal representatives of any Belgian company (registered as such with the ECB, the Crossroads Bank for Enterprises) can log onto to the Mercurius portal using their electronic identity card.

  • In addition, each company, through its main (or local) access manager), can appoint an invoicing manager, who will have access to the Mercurius portal as the company's representative. The role of "Invoicing Manager" is assigned via the “Ma gestion des rôles eGov. For more information on how to access the Mercurius portal, read this fact sheet

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