rekordbox for Mac/WindowsFunctions equivalent to the rekordbox Core plan* are available for free via Hardware Unlock.*Some functions can't be controlled from the DDJ-FLX4.
rekordbox for iOS/AndroidYou can download rekordbox for iOS from the App Store, or rekordbox for Android from Google Play.
Serato DJ LiteYou can use Serato DJ Lite with the unit for free – no license is needed.
Serato DJ ProYou can use Serato DJ Pro with the unit if you buy a license separately.
djay for iOS/AndroidYou can download djay for iOS from the App Store, or djay for Android from Google Play.