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Setting up the Check-in at Work link

Automatically declare your employees' presence to the ONSS: the three checks to make before activating the link.

3 min readUpdated on July 14, 2026

Check-in at Work is the Belgian obligation to register presence on site with the ONSS. Once the link is set up, Shyfter automatically sends the presence declaration as soon as an employee clocks in (check-in) and again at the end of their shift (check-out). You no longer have to enter presences manually on the social security portal.

For this transmission to work, three elements must be correctly filled in. This article covers each of them. If one is missing, the declaration fails and the account administrator receives an error notification.

The Check-in at Work link is an option that must be enabled on your account. If the screens described below do not appear, contact the Shyfter team.

1. Every employee must have a NISS

The NISS (national registry number) identifies the employee to the ONSS. Without it, no declaration can be sent.

Open the profile of each employee concerned and check that the National registry number (NISS) field is filled in with a valid number. An employee without a NISS will trigger an error when clocking in, with the message: the national registry number is missing, complete it in the employee profile.

Tip: in the settings you can enable the icon that flags an invalid NISS next to the user's name. This helps you spot incomplete profiles at a glance.

2. The declaration number must be filled in a "CIAO" attribute

The works declaration number (site declaration) is sent to the ONSS through an attribute of type Location. Shyfter looks for this number in a field named exactly CIAO, so it is essential to respect this naming.

To set it up:

  1. Go to Settings → Attributes → Manage attributes.
  2. Click Add an attributes category.
  3. Give the category a name (for example the name of your site or sites).
  4. Choose the attribute type Location.
  5. Add a field and name it CIAO. This field will hold the declaration number.
  6. Also fill in the location's address: it is used to send the coordinates of the place of work to the ONSS.

The declaration number must contain 13 characters, without a dash. If the format is incorrect, the declaration is rejected and an error is returned to the administrator.

Once the attribute is created, assign it to the shift (or the clocking) of the employee working on that site. It is this link between the clocking and the CIAO attribute that lets Shyfter know which declaration number to send.

3. For subcontractors: the company number in the profile

By default, the declaration is sent under your company's number (VAT). When an employee works as a subcontractor, the declaration must instead state the subcontractor's company number.

To do this, open the employee's profile, go to the Parameters tab, then to the Check In & Out at Work section. Enter the subcontractor's company number in the Subcontractor VAT field.

If this field is filled in, Shyfter uses this number for that employee's declaration. If it is empty, your account's company number is used.

Checklist

Before relying on automatic transmission, make sure that:

  • every employee concerned has a valid NISS in their profile;
  • an attribute of type Location contains a CIAO field with the declaration number (13 characters, no dash), and that this attribute is properly assigned to the relevant shifts or clockings;
  • for subcontractors, the Subcontractor VAT field is filled in the employee's profile.

When these three conditions are met, the presence declaration is sent automatically at clock-in. If there is a problem, the account administrator receives a notification specifying what to correct.

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