Cross-browser WebRTC helpers

npm install rtc
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The rtc module does most of the heavy lifting within the rtc.io suite. Primarily it handles the logic of coupling a local RTCPeerConnection with it's remote counterpart via an rtc-signaller signalling channel.


Build Status unstable

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Getting Started

If you decide that the rtc module is a better fit for you than either rtc-quickconnect or rtc-glue then the code snippet below will provide you a guide on how to get started using it in conjunction with the rtc-signaller and rtc-media modules:

var signaller = require('rtc-signaller')('http://rtc.io/switchboard/');
var rtc = require('rtc');
var media = require('rtc-media');
var localMedia = media();

// render the local media to the document body

// capture local media first as firefox
// will want a local stream and doesn't support onnegotiationneeded event
localMedia.once('capture', function(localStream) {
  // look for friends
  signaller.on('peer:announce', function(data) {
    // create a peer connection for our new friend
    var pc = rtc.createConnection();

    // couple our connection via the signalling channel
    var monitor = rtc.couple(pc, data.id, signaller);

    // add the stream to the connection

    // once the connection is active, log a console message
    monitor.once('connected', function() {
      console.log('connection active to: ' + data.id);

      pc.getRemoteStreams().forEach(function(stream) {


  // announce ourself in the rtc-getting-started room
  signaller.announce({ room: 'rtc-getting-started' });

This code definitely doesn't cover all the cases that you need to consider (i.e. peers leaving, etc) but it should demonstrate how to:

  1. Capture video and add it to a peer connection
  2. Couple a local peer connection with a remote peer connection
  3. Deal with the remote steam being discovered and how to render that to the local interface.



createConnection(opts?, constraints?) => RTCPeerConnection

Create a new RTCPeerConnection auto generating default opts as required.

var conn;

// this is ok
conn = rtc.createConnection();

// and so is this
conn = rtc.createConnection({
  iceServers: []



The cleanup function is used to ensure that a peer connection is properly closed and ready to be cleaned up by the browser.


couple(pc, targetId, signaller, opts?)

Couple a WebRTC connection with another webrtc connection identified by targetId via the signaller.

The following options can be provided in the opts argument:

  • sdpfilter (default: null)

    A simple function for filtering SDP as part of the peer connection handshake (see the Using Filters details below).

Example Usage
var couple = require('rtc/couple');

couple(pc, '54879965-ce43-426e-a8ef-09ac1e39a16d', signaller);
Using Filters

In certain instances you may wish to modify the raw SDP that is provided by the createOffer and createAnswer calls. This can be done by passing a sdpfilter function (or array) in the options. For example:

// run the sdp from through a local tweakSdp function.
couple(pc, '54879965-ce43-426e-a8ef-09ac1e39a16d', signaller, {
  sdpfilter: tweakSdp


Provide the rtc-core/detect functionality.


The generators package provides some utility methods for generating constraint objects and similar constructs.

var generators = require('rtc/generators');


Generate a configuration object suitable for passing into an W3C RTCPeerConnection constructor first argument, based on our custom config.

generators.connectionConstraints(flags, constraints)

This is a helper function that will generate appropriate connection constraints for a new RTCPeerConnection object which is constructed in the following way:

var conn = new RTCPeerConnection(flags, constraints);

In most cases the constraints object can be left empty, but when creating data channels some additional options are required. This function can generate those additional options and intelligently combine any user defined constraints (in constraints) with shorthand flags that might be passed while using the rtc.createConnection helper.


monitor(pc, targetId, signaller, opts?) => EventEmitter

The monitor is a useful tool for determining the state of pc (an RTCPeerConnection) instance in the context of your application. The monitor uses both the iceConnectionState information of the peer connection and also the various signaller events to determine when the connection has been connected and when it has been disconnected.

A monitor created EventEmitter is returned as the result of a couple between a local peer connection and it's remote counterpart.


Apache 2.0

Copyright 2014 National ICT Australia Limited (NICTA)

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at


Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

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