In short: the eBox is an official inbox, not an outbox. It delivers mail from Belgian authorities in digital form, with a date on which it was made available, but you cannot file your reply there. To respond, each organisation keeps its own channel: MyMinfin, an online counter, a form, the post, the department's email address or, in a few remaining cases, the fax.
FaxTelecom sends faxes from a browser to landlines in seven countries, including Belgium. It does not receive faxes and does not assign a number. This article offers general guidance; it does not replace the instructions printed on the letter you received, nor professional advice.
What the eBox does — and what it doesn't
The eBox is the service developed by BOSA (SPF Stratégie et Appui, the Federal Public Service Policy and Support) to gather in one place the documents that Belgian public authorities send to citizens and businesses. You log in with itsme or an eID and a card reader, exactly as on MyMinfin or Mon DOSSIER. Once the eBox is activated, the connected organisations can deposit a tax assessment notice, a certificate, a notification of decision or a reminder letter there.
The point that is often misunderstood: the eBox is one-way. You receive, you read, you download, you archive. There is no "reply to sender" button that would count as an official filing. The reply channel remains the one the authority indicates in the document itself.
A second important point: activating the eBox has a legal effect. From the moment you accept it for a given organisation, delivery into the eBox can replace paper post. In other words, the deadline starts running even if you never check your digital inbox. Anyone who only logs into their public accounts once a quarter is therefore well advised to switch on email notifications and have them land in a mailbox they actually read.
| What the eBox allows | What it does not allow |
|---|---|
| Receiving official letters as PDFs, with the date they were made available | Sending a document to an authority |
| Centralising several organisations in a single interface | Replacing MyMinfin, online social security or a municipal counter |
| Downloading and keeping your documents | Acting as a filing channel in court matters (see e-Deposit and DPA) |
| Getting an email alert for each new document | Guaranteeing that you read the letter in time |
Why the fax survives even though the eBox exists
There is a structural asymmetry between the outbound and the inbound journey. From the authority to you, Belgium has invested in digitisation: eBox, MyMinfin, Mon DOSSIER from the Federal Public Service Home Affairs, health insurance fund portals. From the citizen to the authority, the landscape is far more fragmented. Every federal public service, every municipality, every CPAS (public social welfare centre), every court registry has its own forms, sometimes a generic email address, sometimes a fully fledged electronic counter, sometimes nothing but the physical desk and the post.
The fax fills in what the authorities do not yet cover:
- departments with no online filing option for your specific case (a municipal secretariat, a social services office, a hospital unit);
- last-minute submissions, when the post can no longer guarantee arrival within the deadline and the counter is closed;
- bulky paper attachments (medical files, signed annexes) that you would rather not entrust to unsecured email;
- private counterparties (insurers, landlords, employers, building managers) who still list a fax number in their terms and conditions.
This is not a technological preference, it is simply how things work in practice. And it has a practical consequence: before faxing, you need to know whether the organisation accepts it, because a fax sent to a disconnected number has no effect whatsoever.
Which channel for which procedure?
| Procedure | Counterpart | Preferred channel | Fax? |
|---|---|---|---|
| Reading a tax assessment notice | FPS Finance | eBox or MyMinfin | Not applicable (incoming) |
| Objection against a tax | FPS Finance, competent centre | MyMinfin, otherwise registered post | Backup only, never on its own |
| Request for a municipal grant or certificate | Municipality | Municipal electronic counter | Often accepted |
| Certificate of incapacity for work | Health insurance fund | Fund's portal or app | Sometimes accepted, confirm first |
| Filing submissions or exhibits | Court registry | e-Deposit, DPA-Deposit, registry desk | No, never as a filing |
| Social assistance application | CPAS | CPAS interview and form | For a dated written record, as a supplement |
| Reporting a claim | Insurer | Customer portal or form | Often accepted |
| Unemployment benefits, documents | ONEM, payment institution | Payment institution, portal | Rarely, check first |
The rule running through this table: the official channel always comes first. The fax is only a good choice when the organisation has itself provided for it, or when it backs up a proper submission already on its way.
Three habits to adopt before choosing
1. Reread the letter, not the website
Public websites describe the general procedure; your letter describes your file. It is the letter that carries the name of the department, the reference, the deadline and, often, the decisive sentence: "by post to the address above", "via MyMinfin", "using the enclosed form". One physical folder per procedure, holding the letter received, your documents and your reply, saves you hunting for that information three weeks later; a lever arch file and dividers are more than enough and cost less than a missed follow-up.
2. Check that the number is still live
Fax numbers at Belgian authorities disappear as migrations to VoIP progress. Two precautions beat one failure: take the number from the official page of the department concerned on the very day, and never copy it from an old letter or a third-party directory. Our tool to check a fax number lets you validate the format before sending. We do not publish organisations' numbers: it is up to the department to communicate them, and up to you to take them from the source.
3. Decide what you will have to prove
Proving that a document left and proving that it reached the right office are not the same thing. A fax transmission report attests to the exchange between two machines, the time, the number of pages and the number dialled. That is a useful presumption, not a receipt certified by the authority. For tight deadlines and financial stakes, registered post with acknowledgement of receipt or filing through the official portal remain more solid. The details of what to keep are set out in our article on how to prove a fax was sent.
How to combine both channels intelligently
The most robust approach is not to set the eBox against the fax, but to make them work together within a single procedure.
Step 1 — Gather. Check the eBox and the portal of the organisation concerned. Download the letter you received as a PDF: it carries the file reference, which is essential on your reply.
Step 2 — Prepare the documents. If you are starting from paper, a document scanner with an automatic feeder makes the job far less painful than a smartphone for a twenty-page file, and produces legible PDFs on the first pass. Aim for black and white, 200 dpi minimum, well-contrasted text. Our detailed advice is in the article on how to prepare a PDF for faxing.
Step 3 — Send through the official channel. Filing in MyMinfin, the municipal counter's form, the health insurance fund's portal, registered post: that is the submission that counts legally.
Step 4 — Double up if the deadline is tight. A fax the same day, with a clear cover sheet stating "confirmation of a submission filed today via [channel]" and the file reference, helps a department locate your case and establishes a date. Our fax cover sheet generator prepares that cover page; the details that matter are set out in the article on the fax cover sheet.
Step 5 — Archive. Keep the letter received, the documents you sent, the portal's acknowledgement and the transmission report together. A copy on an external hard drive alongside the cloud prevents losing everything if an account becomes inaccessible at the worst possible moment.
Cases where the eBox excuses you from nothing
Three situations deserve particular attention, because the presence of a document in the eBox does not lighten your obligations.
Court matters. A notification may arrive digitally, but your reply follows the Belgian Judicial Code: filing at the registry, e-Deposit, DPA-Deposit for lawyers, service by a bailiff in the cases provided for. The fax is not an ordinary filing method before Belgian courts, and a document ruled inadmissible means losing the right to act. The subject is covered in detail in our article on faxing a Belgian court.
Tax matters. A tax assessment notice delivered into the eBox starts the objection period running. The expected reply channel is MyMinfin, supplemented where necessary by registered post. We set out these habits in the article on sending a fax to the FPS Finance.
Local matters. Municipalities and CPAS are not all connected in the same way, and their practices vary widely from one entity to another. A small municipality may have a fax machine in the secretariat and no electronic counter at all for your specific procedure. We describe these differences in our guide to faxing a municipality or CPAS.
For professionals: managing the dual track
A Belgian organisation — accountancy firm, medical practice, estate agency, building management company — receives through the eBox and by post, and sends through portals, email and fax. The risk is not the fax itself, it is the absence of a written rule.
A few principles that hold up over time:
- A register of outgoing items, however basic: date, recipient, reference, channel, proof retained. A duplicate delivery note book does the job for small outfits and survives IT outages.
- A directory of numbers checked twice a year, because IP migrations move them without notice.
- No health data or identity documents by unencrypted email: the GDPR applies in full, and a fax landing in a paper tray in a corridor is no more compliant. Our guidance is gathered on the fax and GDPR page.
- A migration plan for analogue lines before the operator decides for you. Our page on the copper switch-off and fax explains the options, from T.38 to online services.
For teams keeping a machine, a T.38-compatible multifunction fax printer avoids most of the negotiation failures seen with low-end analogue adapters plugged in behind a router.
Key takeaways
- The eBox receives, it does not send. Looking for a "reply" button is a waste of time.
- Activating the eBox starts deadlines running even if you never read the mail: switch on notifications and check it regularly.
- The reply channel is the one stated on your letter, not the one that suits you.
- The fax remains a useful backup when the organisation accepts it, when the deadline is tight or when the counterpart is a private party.
- In court and tax matters, the fax never saves a deadline: it accompanies a proper filing.
- Always keep the letter received, the portal's acknowledgement and the transmission report; it is that trio that constitutes proof.
For procedures that still run on fax, our fax an organisation page brings the method together, and the Belgium destinations page sets out what can be reached from a browser. Useful sources to consult directly: the FPS BOSA eBox portal, MyMinfin for tax matters, the FPS Justice website for e-Deposit, and your municipality's website for local procedures.
Topicsbelgiumgovernmentfaxproofhow-todocumentsdeadlines
