Looks like this is geared toward DJ's, EDM people, that kind of thing. Rather confusing...I thought it was maybe virtual instrument and midi only but now I see mentions of audio too. iOS only at the moment.

"Make beats, improvise music and jam live with musicians, beat-makers and DJs all over the world. Join the revolutionary live beats movement today."

https://endlesss.fm/


Motif XF8/YS200/CVP-305/CLP-130/YPG-235/PSR-295/PSS-470
Proteus/1/PROformance Plus/Mo'Phatt
JV-1000/JV-1010/Fantom XR
Krome 61/N1R/X5DR
Kurzweil PC3/PC4
Casio CT-370
Pacifica 112V/M13/HD300/JF-14