Meludia - Listening exercises and to sharpen your ear and music theory skills
Playlist Machinery - Tools that help you create & organize your Spotify playlists
GNU Solfege - GNU Solfege is free music education software.
Heartbeat - Listen to music with your friends together, on Spotify
Perfect Ear - A simple yet advanced application for improving your solfege skills.
Magic Playlist - Get the playlist of your dreams based on a song