Flume Pro licence codes purchased directly are valid for up to use on 5 Macs. Each Mac counts towards an activation, thus it is important to deactivate your licence on Macs you no longer use or own. Read more about activation/deactivation in the help documentation.
Important: If you purchased Flume Pro as an in-app purchase from the Mac App Store, this is not your licence code. You must convert and follow the instructions to migrate your purchase from Apple, in order to receive a Flume Pro licence code.