Tussel

This project is experimental and under active development. APIs will change without notice. Do not use in production.

Tussel is a local-first TypeScript livecoding runtime for pattern-based music, inspired by TidalCycles and Strudel. It runs as a terminal daemon — no browser required.

Status

Work in progress. This is an early-stage experiment. Expect:

• Breaking changes on every commit
• Missing features and incomplete implementations
• Bugs, rough edges, and undocumented behavior
• No stability guarantees whatsoever

If you're looking for a production-ready livecoding environment, use Strudel or TidalCycles instead.

What it does

Tussel takes pattern expressions like:

s("bd sd [hh hh] cp").fast(2).gain(0.8)

and renders them to audio in real time from your terminal. It supports:

• Mini notation — Tidal-style pattern strings ("bd [sd sd] hh")
• Pattern transforms — fast, slow, rev, jux, every, sometimes, and 80+ more
• Signal modulation — sine, saw, rand, perlin as continuous control signals
• Effects — delay, reverb, filters, distortion, phaser, FM synthesis
• MIDI/OSC output — send patterns to external synths and software
• Hot reload — edit your scene file, hear changes immediately
• Offline rendering — export patterns to WAV files

Architecture

pnpm monorepo with 9 packages:

Package	Purpose
@tussel/core	Pattern query engine and transforms
@tussel/dsl	PatternBuilder / SignalBuilder API
@tussel/audio	Web Audio rendering, samples, effects
@tussel/ir	Expression node types, structured logger
@tussel/mini	Mini notation parser
@tussel/runtime	Scene compilation, daemon, Tidal/Strudel adapters
@tussel/cli	CLI entry point
@tussel/parity	Audio comparison tests against Strudel reference
@tussel/testkit	Shared test utilities

Getting started

Requires Node.js >= 20 and pnpm.

pnpm install
pnpm check        # lint + typecheck + test

Run a scene:

./bin/tussel run examples/basic.scene.ts

Acknowledgments

Tussel is a clean-room reimplementation. It does not share code with Tidal or Strudel, but it would not exist without the ideas pioneered by Alex McLean and the TidalCycles/Strudel communities. The pattern language design, mini notation syntax, and many method names originate from their work.

• TidalCycles — GPL-3.0
• Strudel — AGPL-3.0

License

MIT