The collection of the classic (refundable) deposit is possible on Flatio for stays of 180 days or more - however, the landlord must set this deposit in their Flatio web application, the collection of the deposit for this duration is not automatic. If the landlord requires a deposit, you'll see its amount directly in the reservation request section (after entering the move-in and move-out dates) before you create the reservation request. Then in the first and third step of the reservation request process and in the lease agreement.
The deposit is to be transferred to Flatio's bank account on the day of the beginning of the lease agreement (usually on the day of moving in) and you can pay it conveniently through the My Housing application. You can read more about this procedure here.
If you are required to pay a (refundable) deposit even for stays of shorter than 180 days, which isn't systematically possible on Flatio, DO NOT PAY the deposit to the landlord and inform Flatio's Customer Care team immediately. The landlord who requires a deposit for stays of shorter than 180 days, is in violation of Flatio's General Terms and Conditions and their listing may be deactivated.