FitMix 
(formerly SpinMix)
######An online mixing tool that allows fitness professionals and enthusiasts to tailor their music to their workout routines.
If you're a developer, you can check out our style guide
Typically, playlists for workouts and fitness classes are static—at most, they’re themed and ordered for a certain effect. FitMix arms athletes and instructors with extensive control for creating dynamic exercise mixes that follow the structure and intensity of their workouts. Users can enhance their mixes with sound effects and text-to-speech instructions while they clip the best parts of their favorite songs to create invigorating motivational mashups.
FitMix gives athletes powerful tools for editing their music while maintaining a straightforward, intuitive interface. Drag-and-drop reordering, dynamic resizing, and one-click track cropping lets anyone create great mixes with no experience needed.
#Developers
Emily Chesler: Github
Dan Chen: Github
Nick Palenchar: Github | LinkedIn
Matt Bryan: Github