ympd lets you use your web browser to interact with MPD. ympd runs without a dedicated web server or interpreters like PHP, NodeJS or Ruby.
MPD is a powerful server-side application for playing music. In a home environment, you can connect an MPD server to a Hi-Fi system, and control the server using a notebook or smartphone. You can, of course, play audio files on remote clients. MPD can be started system-wide or on a per-user basis.