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/


Yamaha: Motif XF8/YS200/CVP-305/CLP-130/YPG-235/PSR-295/PSS-470
Korg: Krome 61
Kurzweil: PC3
Roland: JV-1000
Casio: CT-370
Kimball Valencia/Broadway/Conn 465/WCOC Reed Organ/Allen ADC-220/Accordions