Mercurius portal help

As explained in the Mercurius section of the page "e-invoicing strategy of the Belgian public sector", the Mercurius platform acts as a central "electronic mail-room" for all Belgian public sector entities. the pages "Mercurius for the private sector"  and "Mercurius for the public sector" provide more specific information applicable to their respective target audience.

This page focuses on the Mercurius Portal, an online tool providing access to the same information to both sender and receiver representatives, so both correspondents can track and trace reception and processing of their e-invoices, centrally and consistently, for all their documents. This tool gives access to both real e-invoices and test e-invoices. Last but not least, this tool includes  an online web-form for suppliers to submit their e-invoices manually. It was added to accommodate the possible lack of IT solutions to transmit e-invoices automatically and cost-effectively - the Government strongly recommends all enterprises to look after real e-Invoicing tools, so that the manual submission of invoices is skipped, for it is the condition for reaping the benefits of e-invoicing.

This page is also the help section of the Mercurius Portal. It consists in the following sections: 


Who can use the Mercurius web site?

There are several target groups:

  1. Occasional suppliers of the Belgian public services, and more frequent suppliers who haven't yet switched to full electronic invoicing (machine-to-machine): they can use the site to create and send their invoices, and to follow up the processing of it. They can also follow up test invoice flows (see further)
  2. Other suppliers: they can follow up the processing of the invoices they issued.
  3. Customers: they can see the list of invoices that were sent to them by all their suppliers, and look at invoice details up to level of exchanged messages. This allows them to handle suppliers questions about invoicing much more efficiently.
  4. IT operators (service providers, customer backend teams, access points,  ...) : they have the possibility to follow up the flows that relate to their services.  (NB: the present help section does not contain specific information for this target group. For more details, please contact the support through the online assistance request form.

What do I need to access and use the site?

You need to use your eID, and you need to have a valid representation of the legal entities for which you want to act.

  1. Belgian eID: we need to identify you with certainty, so the Belgian electronic identity card is required. Assistance to the installation and use of the eID is available on
  2. only authorized individuals can send invoices and consult invoicing flows on behalf of companies (legal entities). All legal representatives recorded in the CBE have automatically access to the site on behalf of their respective legal entities. Other individuals, such as invoicing/accounting responsibles, need to first get the role 'billing officer' assigned to them. The following article discusses how to access the Mercurius Portal in a practical and comprehensive way: "How get access to Mercurius portal?".

What are the main sections of the site?

  • Documents overview:in this page you can see the list of your invoices to all Belgian public entities, up to 24 months in the past. You can use filters to search for an invoice or a subset of invoices. You can define the columns you wish to see. You can also export the list to a text file (.csv)
  • Document details:by clicking on a line of the list you have access to all details of the document (invoice, credit note, ...).
  • message details: by clicking on the links displayed next to the label "Message(s)", you have access to more detailed transmission tracking information (includes the exact message sent and received, intermediate transmission steps...)
  • New invoice / new credit note: to issue an invoice (or a credit note) manually.
  • Preferences:to change language during a session, and to activate the display of explanations at the top of the pages.

If you have specific questions on the use of the site, don't hesitate to generate an issue on online assistance request.

Practical issues (business)

I have sent an invoice. I am waiting for payment. How can I check the status?

Generally, all your questions regarding business processing should be addressed to your business contact, probably the procurement officer of the customer entity. In parallel, notice that the site offers you access to information regarding your flow of invoices. Besides, the procurement officer of your customer entity also has access to this information (ie, his flow  of incoming invoices). This is of great help in the communication about common invoices.

Here are practical explanations about the features of the site:

  • You can look for the invoice using its number, its sender, its receiver, the date of issuance (or a range).
  • If you do not retrieve the invoice then it means that it was not received by the Belgian authorities. Something may have gone wrong in the system that issues the invoice. Contact the team responsible for this system.
  • Once you retrieved the invoice, you can look at the invoice details. It contains a status field:
    • Received: the invoice has been received by the authorities;
    • processed: the received invoice has been booked in the accounting system;
    • rejected: the received invoice was rejected – probably something was not correct in the invoice (i.e. the Purchase Order number not mentioned)
  • Additionally, you can look at the messages exchanged: the field "related messages" lists all message-exchanges between the sender and the receiver. The minimum is one message, ie the invoice itself. A classic pattern is: (a) one message for the invoice (b) one message for the attachment (on Mercurius it is handled as a separate message); (c) one message for the receiver feedback after processing the attachment (d) one message for the receiver feedback after processing the invoice.

Other articles about this subject:

New invoice: I don't find my customer in the list.

Not all governmental entities are ready to receive invoices. If your customer does not appear in the customer selection list/search field, then it is probably not yet ready. Please contact your customer's procurement responsible. Tip: to be certain about the official name of your customer ask its enterprise number and look for the corresponding official name on Crossroads Bank for Enterprises (CBE)

New invoice: supplier name does not appear, only enterprise number. How comes?

This applies only to occasional suppliers, who have no machine-to-machine invoicing flows in place. The first time you use the site, the name of your company is not recorded. So the site only knows your enterprise number. If you create a new invoice, then the first time you must enter the company name in the corresponding field. From then on, the site will use this information instead of the enterprise number, in the suppliers selection list.

Practical issues (IT, access...)

I have an eID but I don't know how to use it.

Please visit This site contains all the information required to install and use the eID. If you still have issues then please fill in our online assistance request form.

I have logged in but I receive an error message 'Sorry, you are not registered as company legal representative or billing officer'.

It means that the site has not found a link between you and a legal entity ( a company or public administration). Please refer to 'What do I need to access and use the site?'

Mercurius, legal functions and roles management (billing_officer)


As stated in section "What do I need to access and use the site?"', only authorized individuals can send invoices and consult invoicing flows on behalf of companies (legal entities). The usual way to holding such an authorization is being a legal function holder, duly recorded in the CBE. The CBE Public Search site allows you to control the list of such functions: Crossroads Bank for Enterprises (CBE).

The other option is to use the eGOV roles management system. This system is available for all legal entities. It gives them the possibility to assign and revoke roles to their employees (or subcontractors), to perform administrative duties online on their behalf, in eGOV applications (such as the Mercurius web site). However, to be able to use it, a chief access manager must be designated by a legal function holder. Optionally, the chief access manager can appoint a (local) access manager for the domain "Finance". If there is no chief access manager for your company, or if you don't know him, then you must first contact CSAM to know the person in charge of this responsibility, or initiate the assignment of a chief access manager. These managers will be able to designate billing officers for their enterprise, using the tool My eGov role management).

In practice

The following article discusses how to access the Mercurius Portal in a practical and comprehensive way: "How get access to Mercurius portal?"

Mercurius/Production, Mercurius/Test: what is it about?

Electronic invoicing, as any electronic exchange flow, can be very easy or very tricky. Therefore Mercurius exists in two operating modes:

  • Production: is the standard mode. It is the mode to use by suppliers to issue invoices and consult the lists of invoices sent to public authorities, and by customers to consult the list of invoices received from their suppliers
  • Test: in this operating mode, the site shows the data exchanged between test environments of the suppliers and customers. For the rest, this mode is fully similar to the production mode. It allows to suppliers to send test invoices to customers and validate whatever needs validation before sending real invoices. It allows suppliers and customers to look after test invoices during end-to-end test activities, based on a common view on the exchanged data.

I still have questions, remarks, suggestions.

If you still have questions after going through this FAQ list, then please fill in our online assistance request form. Our support staff will handle your request. Please be aware that providing correct, detailed and specific information makes user support much more efficient.