Run your Pure Data patches on the web.
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experimental fork

Using this fork to expand available Pd objects.

The code will not be up to the standards of WebPd - as I am using a lot of global variables for testing in the console.

Features added:

adc~ (web audio input) - Only works on Chrome desktop - partially complete. Uses 1 channel currently and no inlets on the object. This was kind of a hack. The input stream connects to a scriptNode that copies samples to a circular buffer. The scriptNode connects to a gainNode with gain value of zero, which connects to context.destination. This was the only way I could get WebAudio to pull the stream through the scriptNode.

Latency is about 3000 samples in addition to existing latency. If we find a more efficent way to buffer the samples than the hack described above...

Working on:
  • snapshot~
  • more DSP operators
  • fft~ (yeah right)

Original readme from sebpiq:

NEWS : A big refactoring is underway. Main goal is to port all WebPd to Web Audio API. You can follow progress here :

Build Status


  • WebPd is a 100% JavaScript Pure Data runtime. It aims at allowing a subset of Pure Data audio patches to run in the browser without plugins.

  • WebPd is also a standalone DSP library. Every object as you know it in Pure Data exposes a complete API, allowing developers to control everything with JavaScript.

  • checkout the gallery.

Browser support

Firefox 4.0+ | Chrome 10.0+ | Safari 6.0+

What doesn't work yet

Very little of the full Pure Data functionality has been implemented yet. To check-out which objects are implemented, you can use the WebPd gui. Internal messages, abstractions, subpatches and externals haven't been implemented yet. Also, before testing your patch remove all controls (bangs, atoms, sliders, ...), because those are not supported yet.

But everything is not lost !!! There is way enough objects to have fun. Always test your patches with the WebPd gui. Also, the library is currently under (rather) heavy development, so stay tuned, more features will come soon. Also, check-out the roadmap.

Getting started

Note : for documentation about Pd objects or tutorials about how to make Pd patches, please refer to the official Pure Data documentation.

Note : there is a complete (but simple) example in demos/sound-check. Also online here.

Go to "dist/", download the last stable version of webpd-min.js (click on the file, click on "raw", save the file) and include it in your webpage.

<!DOCTYPE html>
        <script src="webpd-min.js"></script>

Then, get a Pd file, load it to a WebPd patch and start it. The way you get the Pd file in JavaScript is up to you, ... but the prefered way is by using an Ajax request. For this I suggest to use JQuery :

<!DOCTYPE html>
        <script src="webpd-min.js"></script>
        <script src="jquery.js"></script>
            $.get('myPatch.pd', function(patchFile) {       // Getting the Pd patch file
                var patch = Pd.compat.parse(patchFile);     // Loading the WebPd patch
      ;                               // Starting it

Note : when developing on your computer Ajax requests might fail. See troubleshooting section.

If the patch file is not too big, you can also include it directly in your page, and read it with JavaScript :

        <script src="webpd-min.js"></script>
        <script id="patchFile" type="text/pd">
            #N canvas 199 234 519 300 10;
            #X obj -114 170 osc~ 440;
            #X obj -108 246 dac~;
            #X connect 0 0 1 0;
            var patchFile = document.getElementById('patchFile').text;      // Getting the Pd patch file
            var patch = Pd.compat.parse(patchFile);                         // Loading the WebPd patch
  ;                                                   // Starting it

Sending / receiving messages

To receive messages from named senders within the patch (aka. send boxes : [send someName]), call the receive method of the patch object :

patch.receive('someName', function(msg) {
    console.log('received a message from "someName" : ', msg);
    // your code ...

In return, you can send messages from JavaScript to a named sender within the patch (aka. receive boxes : [receive someName]) by calling the send method of the patch object :

patch.send('someName', 'hello!');

Note : there is a an example of this in demos/send-and-receive. Also online here.


There's a bunch of demos in demos (surprisingly :) :

  • sound-check a complete example to help you getting started.
  • send-and-receive a complete example for sending/receiving messages.
  • processing-storm an example of using WebPd with processing.
  • random-drones a simple experiment, generating very simple random drone patches.
  • simple-gui a very simple GUI for WebPd. Also documents the dynamic patching API.

Note : To run those demos on your own computer, you will need to build webpd-latest.js first. For this, follow the build instructions bellow, or simply copy the latest stable build to dist/webpd-latest.js. For example, if latest build is webpd-0.2.0.js :

cp dist/webpd-0.2.0.js dist/webpd-latest.js


> I can't run the demos on my computer / PD files won't load

For security reasons, browsers control access to your file system from web pages. Because of this, getting Pd files with Ajax might fail on your local machine.

A workaround for Chrome is to launch it from a terminal with the option --allow-file-access-from-files.

For any browser, you can also start a local HTTP server. For example, if you have Python installed, go to the root directory of your project, run :

python -m SimpleHTTPServer

then point your browser to localhost:8000/my_page.html.

For example, to run the processing-storm.html demo, open a terminal, go to WebPd/, start the python server, and point your browser to localhost:8000/demos/processing-storm/processing-storm.html.

Instructions for building webpd.js

To build webpd.js and webpd-min.js yourself, you will need node.js and Grunt. Follow the instructions to install those, then in WebPd's root folder run :

grunt build

Instructions for running the tests

You can run the tests either with grunt, by running the command :

grunt test

Or by opening test/index.html in your browser.


Any kind of contribution would be very very welcome. Check out the issue tracker or contact me directly.