supercollider.js is a Node.js library for communicating with and controlling SuperCollider.

SuperCollider is a platform for audio synthesis and algorithmic composition, used by musicians, artists, and researchers working with sound. It is free and open source software available for Windows, Mac OS X, and Linux.

SuperCollider consists of two executables: scsynth and sclang.


A real-time audio server. It features 400+ unit generators (“UGens”) for analysis, synthesis, and processing. Some of the audio techniques it supports include additive synthesis, subtractive, FM, granular, FFT, and physical modelling. You can write your own UGens in C++, and users have already contributed several hundred more in the sc3-plugins repository.

supercollider.js can communicate fluidly with it:

let sc = require('supercolliderjs');

sc.server.boot().then((server) => {

  // Compile synthDef from a file
  // Will recompile and send to server if the file changes.
  let def = server.loadSynthDef('formant', './formant.scd');

  // Create group at the root
  let group =;

  let freqSpec = {
    minval: 100,
    maxval: 8000,
    warp: 'exp'

  // Map 0..1 to an exponential frequency range from 100..8000
  let randFreq = () =>, freqSpec);

  let spawn = (dur) => {
    server.synth(def, {
      fundfreq: randFreq(),
      formantfreq: randFreq(),
      bwfreq: randFreq(),
      pan:, 1, -1, 1, Math.random()),
      timeScale: dur
    }, group);

    let next = Math.random() * 0.25;
    // Schedule this function again:
    setTimeout(() => spawn(next), next * 1000);


Coming soon:


SuperCollider language is an interpreted programming language similar to Smalltalk or Ruby with syntax similar to C or Javascript. The interpreter itself is called sclang. It communicates with scsynth via OSC. You can use sclang for algorithmic sequencing, connecting your app to external hardware including MIDI controllers, or writing GUIs and visual displays. sclang is extensible via the Quarks package system.

Interpreting SuperCollider language code from JavaScript:

var sc = require('supercolliderjs');

sc.lang.boot().then(function(sclang) {

    .then(function(result) {
      // Result is a native JavaScript array
      console.log('= ' + result);
    }, function(error) {
      // syntax or runtime errors are returned as JavaScript objects

    .then((result) => {
      // Loads and executes the document.
      // The last thing in the source file is returned, converted to equivalent JavaScript types where possible.
    }, console.error);

}, function(error) {
  // sclang failed to startup:
  // - executable may be missing
  // - class library may have failed with compile errors