- jasmid - MIDI file reader and synthesizer. Last updated April 2014.
- WebMidi.js - High level API for Web MIDI. Last updated less than a month ago.
- JZZ - High-level library for midi sending and receiving.
- MIDIPlayer
- sf2-parser
- soundfont-player
- residentSf2Synth
- MIDI.js - MIDI sequencer and soundfont-based synth.
- smfplayer (logue)
- smfplayer (ryoyakawai)
- WebMidiLink - Protocol/spec for multiple web-based synthesizers to be synchronized and used from a host application, like plug-ins.
- WebSequencer - HTML MIDI sequencer