Question about Hercules Inpulse 500

Rekordbox has some MIDI-capable functions, but there is no built-in support for non-Pioneer controllers. So you will have problems using Rekordbox.

I no longer have my Inpulse 500, as I have switched to other Pioneer models, and can only confirm that the Inpulse 500 is compatible with Virtual DJ. As far as I know, a Rekordbox licence is always included with Pioneer DJ controllers; my favourite is and remains Virtual DJ, also as a recommendation.