If you want to work in Slovakia, you have to meet different conditions depending on the type of your residence permit, the type of work you want to perform, the length of your stay, and other factors.
If you fulfil certain conditions, your employer does not need to confirm that it was not possible to fill in the vacancy with a Slovak national (single permit). You might also not need a work permit. You can check this list here
In other cases, you will need to apply for one of the following documents: ·
work permit; ·
If you require a work permit, confirmation of the possibility to fill a vacancy (single permit), or if you hold an EU Blue Card, you are only entitled to perform work within an employment relationship (contract of employment). In other cases, you may also perform work on the basis of an agreement other than a contract of employment.