Gesture Synth on GitHub: the two projects behind the trend
Short answer: "gesture synth" became a search term in late July 2026 after two open-source browser instruments appeared within days of each other: ericwei97-cloud/gesture-synth, whose Vercel demo URL gave the world the phrase "gesture synth weld", and Ekmand/gesture-synth at gesturesynth.com. Both use MediaPipe hand tracking and the Web Audio API. HandSynth builds on the same idea with its own code.
Eric Wei's gesture-synth (the "weld" demo)
- Play: gesture-synth-weld.vercel.app
- Controls: left hand chooses the chord by finger count with a tilt for major or minor; right hand sets inversions, octave, filter and volume.
- Sounds: four presets (Warm, Bright, Retro, Strings and Horns) and twelve keys.
- Stack: plain JavaScript, Vite, MediaPipe Hand Landmarker, Web Audio.
- Licence: free for educational and non-commercial use with credit; not an open-source licence in the OSI sense.
- Known issues: the chord display can stick when the left hand leaves the frame, and oscillators are not disconnected, which leaks memory in long sessions (both are open issues on the repository).
Ekmand's gesture-synth
- Play: gesturesynth.com
- Controls: gesture mode with Roman-numeral chords on the left hand (index plus pinky for VI, plus thumb for VII) and volume, voicing, filter and octave on the right; a theremin mode with left-hand volume and right-hand pitch.
- Extras: first-visit tutorial, guided practice for community songs, settings, deep links backed by Supabase.
- Stack: TypeScript, Vite, MediaPipe, Web Audio.
- Licence: none shown in the repository at the time of writing.
Why the term took off
Short videos of someone conducting chords out of thin air are irresistible, and the demos needed no install. Google Trends shows the query appearing from nothing on 20 July 2026, peaking within a week and settling into a steady plateau. Within eight weeks a dozen look-alike sites had registered every gesturesynth domain. We list only the originals and genuinely different instruments in the hub.
How HandSynth differs
HandSynth keeps the two-hand idea because it works, and adds what the originals leave out: a theremin mode with note snap on its own page, mouse, touch and keyboard modes for devices without a camera, a beat and drums, WAV recording, MIDI out to a DAW, one-hand play with automatic voicing, and a fix for the stuck-note and memory-leak issues. The code is written from scratch, so the non-commercial licence of the original does not apply, and we credit both projects on every page. The how it works guide describes the implementation.