Funkwhale
Self-hosted music streaming and sharing in the Fediverse. ActivityPub-based — instances can federate so you can follow music libraries on other servers. An open source alternative to Spotify/SoundCloud for those who want to own their library.
Features: upload your own library, stream, share with federated instances, podcast support, radio. Subsonic-API compatible → works with existing music apps (DSub, Symfonium). Use case: a group of musicians shares freely licensed music between instances, or an individual hosts their own library. Distinct from Spotify: no catalog licensing, you provide the content yourself. Part of the "the Fediverse is more than Twitter clones" movement alongside PeerTube (video), Pixelfed (photo), BookWyrm (books).