Free browser music instruments

VestApps by deciBelboy

A growing suite of single-file browser instruments.
No install. No account. Open a tab and make music.

↓ Choose an instrument

8 instruments Free forever VestLink sync Works offline

The suite — pick one, or open them all

Groovebox · Standalone

Karplus-Strong string synth, dual-kit drums (909 + Linn LM-1), 303-style acid bassline, dub delay and cassette recorder — all in one tab. Runs standalone (no VestLink sync).

16-step 303-style acid sequencer. Tap to toggle, long-hold to accent, swipe for slide/tie. Cutoff, resonance, env depth, decay and transistor-crunch drive.

16-step drum machine with classic kit sounds, groove selection, gated reverb, fill button and dub delay send.

Dedicated Karplus-Strong physical-model string synthesiser. Multiple reverb types, generative sequencing, expressive pluck control.

Arpeggiator Synth

Polyphonic arpeggiator with oscillator stack, filter/envelope, effects, dub send, patch matrix and cassette recorder. Deep modulation in a single file.

Glitch Percussion

Clock-derived glitch percussion with Euclidean rhythms. Four synthesis voices — Clock, Crush, Ring and Chaos — all quantised to key and scale.

Melodic Sequencer

8-step melodic sequencer. Snap to scale, sync BPM and root note via VestLink. Pairs with every other app in the suite.

Web audio sampler with Turing Machine-style step sequencer. Per-channel Density/Sustain knobs, ASR envelopes, dub send and MIDI learn.

Cross-app sync

Open two tabs (or more).
They lock together.

VestLink is built into every app. Enable it in two tabs and BPM, key, scale and transport stay locked instantly — no setup, no server, no lag. All apps share the same domain so sync just works.

Syncs BPM, root note, scale and Play/Stop across all open tabs
Works across any number of tabs simultaneously
VestLink Network extends sync across devices via WebRTC
Change key in one app — every other tab updates instantly
Zero servers, zero config — localStorage under the hood

✦ A special gift ✦

Session Recorder

Never lose a
happy accident.

TapeVest sits quietly alongside every other app in the suite, ready to capture whatever you make. Record up to 6 minutes directly in the browser, scrub playback on the cassette reel, and export as a 192 kbps MP3 — no DAW, no interface, no fuss.

Up to 6 min recording 192 kbps MP3 export Scrub playback No install