A sampler and sequencer in the shape of a late-90s hardware drum machine, running entirely in the browser. Chop a break onto the pads, record a sequence, mix it down. Free, MIT-licensed, works offline, and installs as a desktop app — no account needed to make a beat.
The 16-bit samplers that built a lot of records are now secondhand, expensive, and mostly sitting in closets. Chop Deck is one of them rebuilt as a web page. The URL is the app: you load it and look down at the machine, and everything happens on the LCD and the front panel the way it did on the hardware.
What it does
Ninety-nine sequences of sixty-four tracks at 96 ppq — real-time and step recording, timing correct with swing, note repeat, loop record, punch, undo, song mode. Underneath that a thirty-two voice sampler: twenty-four programs, four drum slots, a resonant low-pass filter, envelopes, velocity modulation, mute groups.
You sample from a microphone or from the machine itself, then trim, loop, slice a zone across the pads, time-stretch and resample. There is a mixer with per-note level and pan, two multi-effect chains, two reverbs, and Web MIDI in and out for pads, clock and footswitches.
Files live on a browser disk with real folders. Standard MIDI files and WAVs go in and out, projects export as bundles, and it autosaves.
How it’s built
TypeScript, with the firmware separated from the sound. src/kernel/ is the machine’s operating logic — modes, screens, fields, the cursor, the DATA wheel — and src/screens/ holds one file per mode where every screen is a pure function of machine state. That means the whole interface can be asserted as text in unit tests, which is what makes a machine this stateful tractable to change. The audio engine, the DSP and the offline bounce sit behind their own boundary in src/audio/.
It has its own design system, the same way this site does — tokens first, components ported from them.
Where it runs
The build output is the whole instrument as static files. Serve it from a web server, a USB stick, or nothing at all: with no site behind it the machine notices and hides the site’s links. Tauri wraps the same build in a native window for Windows, macOS and Linux.
The account on chopdeck.com is optional and always was. It carries a project between computers, adds libraries of kits and public-domain samples, and lets you publish a beat for someone else to open and remix. Skip it and the machine still works offline, with no ads and no tracking.
Source is at github.com/mcinnisdev/chopdeck, MIT — though the name and the mark are not part of the licence, and forks are asked to pick their own.