This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The createDataChannel() method on the RTCPeerConnection interface creates a new channel over which any kind of data may be transmitted. This can be useful for back-channel content such as images, file transfer, text chat, game update packets, and so forth.

If the new data channel is the first one added to the connection, renegotiation is started by delivering a notificationneeded event.


dataChannel = RTCPeerConnection.createDataChannel(label[, options]);


A human-readable name for the channel. null is treated as if you specified an empty string (""). This string may not be longer than 65,535 bytes.
options Optional
An RTCDataChannelInit dictionary providing configuration options for the data channel

RTCDataChannelInit dictionary

The RTCDataChannelInit dictionary provides the following fields, any of which may be included as needed in the object passed as the options parameter in order to configure the data channel to suit your needs:

ordered Optional
Indicates whether or not messages sent on the RTCDataChannel are required to arrive at their destination in the same order in which they were sent (true), or if they're allowed to arrive out-of-order (false). Default: true.
maxPacketLifeTime Optional
The maximum number of milliseconds that attempts to transfer a message may take in unreliable mode. While this value is a 16-bit unsigned number, each user agent may clamp it to whatever maximum it deems appropriate. Default: null.
maxRetransmits Optional
The maximum number of times the user agent should attempt to retransmit a message which fails the first time in unreliable mode. While this value is a16-bit unsigned number, each user agent may clamp it to whatever maximum it deems appropriate. Default: null.
protocol Optional
The name of the sub-protocol being used on the RTCDataChannel, if any; otherwise, the empty string (""). Default: empty string, "". This string may not be longer than 65,535 bytes.
negotiated Optional
Indicates whether or not the two peers negotiated when creating the data channel (true), or if the channel was simply created by one of the peers, letting the other peer choose to accept the connection or not when it receives the resulting RTCDataChannelEvent (false). Default: false.
id Optional
A 16-bit numeric ID for the channel. If you don't include this option, the user agent will select an ID for you.

The options which can be configured using the RTCDataChannelInit dictionary represent the script-settable subset of the properties on the RTCDataChannel interface.

Return value

A new RTCDataChannel object with the specified label, configured using the options specified by options if that parameter is included; otherwise, the defaults listed above are established.


The RTCPeerConnection is closed.
The label and/or protocol string is too long; these cannot be longer than 65,535 bytes (bytes, rather than characters).
Values were specified for both the maxPacketLifeTime and maxRetransmits options. You may only specify a non-null value for one of these.
An id was specified, but another RTCDataChannel is already using the same value.


This simple example opens a channel and sets up handlers for the open and message events to send and receive messages on the data channel. For a more thorough example showing how the connection and channel are established, see A simple RTCDataChannel sample.

var pc = new RTCPeerConnection();
var channel = pc.createDataChannel("Mydata");
channel.onopen = function(event) {
  channel.send('sending a message');
channel.onmessage = function(event) {


Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browser
The definition of 'createDataChannel()' in that specification.
Working Draft Initial definition.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support (Yes) 22 (22) ? ? ?
Feature Android Android Webview Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support No support No support 24.0 (24) ? [2] ? ? ? (Yes)

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

API createDataChannel Experimental Media Reference RTCPeerConnection WebRTC