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r0astr

Multi-instrument live coding for the web

Create music with code. Control four independent instruments with a synchronized clock. Tweak parameters in real-time with sliders. Perfect for live performances and creative exploration.

  • Try It Now

    Launch r0astr directly in your browser. No installation required.

    Launch App

  • Download

    Get the desktop app with remote control and offline features.

    Download

What is r0astr?

r0astr is a multi-instrument live coding interface built on Strudel. Write patterns in code, hear them instantly, and perform live.

  • :material-music-note-multiple: Multiple Instruments

    Four independent cards, each running its own pattern. Drums, bass, melody, ambient – layer them all.

  • Perfect Sync

    All instruments share a clock. Start and stop cards freely – they always stay in time.

  • Live Sliders

    Add slider() to any parameter. Tweak filters, tempo, and effects in real-time.

  • Code as Music

    Write patterns using Strudel's mini notation. Powerful yet beginner-friendly.

See It In Action

Demo video coming soon

Try the live app instead →

Features

  • Cards Interface

    Each card is an independent instrument with its own pattern editor and controls.

    Learn about Cards

  • Master Panel

    Global controls for tempo and effects that apply across all instruments.

    Master Panel Guide

  • Remote Control

    Control r0astr from your iPad or phone. Perfect for live performances.

    Remote Setup

  • Powered by Strudel

    Built on the powerful Strudel pattern language, a JavaScript port of TidalCycles.

    Strudel Docs

Quick Example

Paste this into Card 1 and hit Play:

s("bd*4, ~ sd ~ sd, hh*8").gain(0.8)

Add this to Card 2 for bass:

note("c2 ~ c2 e2").s("sawtooth").lpf(400).gain(0.6)

Both patterns play in perfect sync. More patterns

Get Started

  • Quick Start

    Create your first pattern in 5 minutes.

    Getting Started

  • Learn

    Understand concepts, patterns, and features.

    Learning Path

  • Download

    Get the desktop app for macOS, Windows, or Linux.

    Downloads

Open Source

r0astr is open source under the AGPL-3.0 license.

View on GitHub Contribute