Songmate

Next release will let you play your friends songs the same way you play your own.

Quick note on the requirements. You must have a Spotify premium account, and Songmate can only play on devices with Spotify Connect linked. This could be your Alexa device, your Spotify mobile app, desktop app or Spotify web player.

Went live on Alexa! To try it ask Alexa to open Songmate. Once your Spotify songs have been analysed, you can ask things like "Play happy rock", "Play 70s songs", "Shuffle radio", "Play energetic songs", "Play sad songs", etc. You can find a more complete list of instructions on the website