The community for ongoing Spotify Connect research and the librespot-org/librespot project.
Spotify Web API Wrapper with Retrofit and OkClients just for Android. This library includes authentication and account token management feature.
A QT5 Spotify client, based on MeeSpot with support for Ubuntu Touch and SailfishOS.
Low-level Ruby bindings for libspotify, the official Spotify C API
Spotify-ed: Music Recommendation and Discovery in Spotify