Limit access to your Spotify account to ONE playlist. Designed for those who want to share music from Spotify with their kids and not worry about what music they are getting into.
Its simple:
Log in to your Spotify account
Pick a playlist
The app will now load the playlist automatically and only allow songs to be played that are on that playlist. You can add or remove songs from the playlist in Spotify and the changes will appear in Listify when you refresh the list.
You do NOT need Spotify on the device that you run Listify, but it does use your Spotify account, so you can only stream from one device at a time.