RTCDataChannel

The RTCDataChannel interface represents a network channel which can be used for bidirectional peer-to-peer transfers of arbitrary data. Every data channel is associated with an RTCPeerConnection, and each peer connection can have up to a theoretical maximum of 65,534 data channels (the actual limit may vary from browser to browser).

To create a data channel and ask a remote peer to join you, call the RTCPeerConnection's createDataChannel() method. The peer being invited to exchange data receives a datachannel event (which has type RTCDataChannelEvent) to let it know the data channel has been added to the connection.

Properties

Also inherits properties from: EventTarget

binaryType
The property binaryType on the RTCDataChannel interface is a DOMString which specifies the type of JavaScript object which should be used to represent binary data received on the RTCDataChannel. Values allowed by the WebSocket.binaryType property are also permitted here: "blob" if Blob objects are being used or "arraybuffer" if ArrayBuffer objects are being used. The default is "blob".
bufferedAmount Read only
The read-only RTCDataChannel property bufferedAmount returns the number of bytes of data currently queued to be sent over the data channel.
bufferedAmountLowThreshold
The RTCDataChannel property bufferedAmountLowThreshold is used to specify the number of bytes of buffered outgoing data that is considered "low." The default value is 0.
id Read only
The read-only RTCDataChannel property id returns an ID number (between 0 and 65,534) which uniquely identifies the RTCDataChannel.
label Read only
The read-only RTCDataChannel property label returns a DOMString containing a name describing the data channel. These labels are not required to be unique.
maxPacketLifeTime Read only
The read-only RTCDataChannel property maxPacketLifeTime returns the amount of time, in milliseconds, the browser is allowed to take to attempt to transmit a message, as set when the data channel was created, or null.
maxRetransmits Read only
The read-only RTCDataChannel property maxRetransmits returns the maximum number of times the browser should try to retransmit a message before giving up, as set when the data channel was created, or null, which indicates that there is no maximum.
negotiated Read only
The read-only RTCDataChannel property negotiated indicates whether the RTCDataChannel's connection was negotiated by the Web app (true) or by the WebRTC layer (false).
ordered Read only
The read-only RTCDataChannel property ordered indicates whether or not the data channel guarantees in-order delivery of messages; the default is true, which indicates that the data channel is indeed ordered.
protocol Read only
The read-only RTCDataChannel property protocol returns a DOMString containing the name of the subprotocol in use. If no protocol was specified when the data channel was created, then this property's value is "" (the empty string).
readyState Read only
The read-only RTCDataChannel property readyState returns an enum of type RTCDataChannelState which indicates the state of the data channel's underlying data connection.
reliable Read only
The read-only RTCDataChannel property reliable indicates whether or not the data channel is reliable.
stream Read only
The deprecated (and never part of the official specification) read-only RTCDataChannel property stream returns an ID number (between 0 and 65,535) which uniquely identifies the RTCDataChannel.

Event handlers

Also inherits event handlers from: EventTarget

onbufferedamountlow
The RTCDataChannel.onbufferedamountlow property is an EventHandler which specifies a function the browser calls when the bufferedamountlow event is sent to the RTCDataChannel. This event, which is represented by a simple Event object, is sent when the amount of data buffered to be sent falls to or below the threshold specified by the channel's bufferedAmountLowThreshold.
onclose
The RTCDataChannel.onclose property is an EventHandler which specifies a function to be called by the browser when the close event is received by the RTCDataChannel. This is a simple Event which indicates that the data channel has closed down.
onclosing
The RTCDataChannel.onclosing property is an EventHandler which specifies a function to be called by the browser when the closing event is received by the RTCDataChannel. This is a simple Event which indicates that the data channel is being closed, that is, RTCDataChannel transitions to "closing" state. For example, after RTCDataChannel.close() was called but the underlying data transport might not have been closed yet.
onerror
The RTCDataChannel.onerror property is an EventHandler which specifies a function to be called when the error event is received. When an error occurs on the data channel, the function receives as input an ErrorEvent object describing the error which occurred.
onmessage
The RTCDataChannel.onmessage property stores an EventHandler which specifies a function to be called when the message event is fired on the channel. This event is represented by the MessageEvent interface. This event is sent to the channel when a message is received from the other peer.
onopen
The RTCDataChannel.onopen property is an EventHandler which specifies a function to be called when the open event is fired; this is a simple Event which is sent when the data channel's underlying data transport—the link over which the RTCDataChannel's messages flow—is established or re-established.

Methods

Also inherits methods from: EventTarget

close()
The RTCDataChannel.close() method closes the RTCDataChannel. Either peer is permitted to call this method to initiate closure of the channel.
send()
The send() method of the RTCDataChannel interface sends data across the data channel to the remote peer.

Events

bufferedamountlow
Sent to the channel's onbufferedamountlow event handler when the number of bytes of data in the outgoing data buffer falls below the value specified by bufferedAmountLowThreshold.
close
Sent to the onclose event handler when the underlying data transport closes.
error
Sent to the onerror event handler when an error occurs on the data channel.
message
Sent to the onmessage event handler when a message has been received from the remote peer. The message contents can be found in the event's data property.
open
Sent to the onopen event handler when the data channel is first opened, or when an existing data channel's underlying connection re-opens.

Data format

The underlying data format is defined by the IEEE draft specification draft-ietf-mmusic-sctp-sdp. The current format specifies its protocol as either "UDP/DTLS/SCTP" (UDP carrying DTLS carrying SCTP) or "TCP/DTLS/SCTP" (TCP carrying DTLS carrying SCTP). Older browsers may only specify "DTLS/SCTP".

Example

var pc = new RTCPeerConnection();
var dc = pc.createDataChannel("my channel");

dc.onmessage = function (event) {
  console.log("received: " + event.data);
};

dc.onopen = function () {
  console.log("datachannel open");
};

dc.onclose = function () {
  console.log("datachannel close");
};

Specifications

Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browsers
The definition of 'RTCDataChannel' in that specification.
Candidate Recommendation Initial specification.

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
RTCDataChannel
Experimental
Chrome Full support YesEdge Full support ≤79Firefox Full support 24
Full support 24
No support 18 — 60
Alternate Name
Alternate Name Uses the non-standard name: DataChannel
IE No support NoOpera Full support YesSafari Full support YesWebView Android Full support 4.4Chrome Android Full support 29Firefox Android Full support 24
Full support 24
No support 18 — 60
Alternate Name
Alternate Name Uses the non-standard name: DataChannel
Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support 2.0
binaryType
Experimental
Chrome Full support YesEdge Full support ≤79Firefox Full support 18IE No support NoOpera Full support YesSafari Full support YesWebView Android Full support 4.4Chrome Android Full support 29Firefox Android Full support 18Opera Android Full support YesSafari iOS No support NoSamsung Internet Android Full support 2.0
bufferedAmount
Experimental
Chrome Full support 56Edge Full support ≤79Firefox Full support 18IE No support NoOpera Full support 43Safari Full support YesWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support 18Opera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
bufferedamountlow eventChrome Full support 57
Notes
Full support 57
Notes
Notes The default for rtcpMuxPolicy is require.
Edge Full support ≤79
Notes
Full support ≤79
Notes
Notes The default for rtcpMuxPolicy is require.
Firefox Full support YesIE No support NoOpera Full support 44
Notes
Full support 44
Notes
Notes The default for rtcpMuxPolicy is require.
Safari Full support YesWebView Android Full support 57
Notes
Full support 57
Notes
Notes The default for rtcpMuxPolicy is require.
Chrome Android Full support 57
Notes
Full support 57
Notes
Notes The default for rtcpMuxPolicy is require.
Firefox Android Full support YesOpera Android Full support 43
Notes
Full support 43
Notes
Notes The default for rtcpMuxPolicy is require.
Safari iOS No support NoSamsung Internet Android Full support 7.0
Notes
Full support 7.0
Notes
Notes The default for rtcpMuxPolicy is require.
bufferedAmountLowThreshold
Experimental
Chrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari Full support YesWebView Android Full support 56Chrome Android Full support 56Firefox Android No support NoOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
closeChrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
close eventChrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari ? WebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
error eventChrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari ? WebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
id
Experimental
Chrome Full support 56Edge Full support ≤79Firefox No support NoIE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android No support NoOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
label
Experimental
Chrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
maxPacketLifeTime
Experimental
Chrome Full support 56Edge Full support ≤79Firefox Full support 62IE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support 62Opera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
maxRetransmits
Experimental
Chrome Full support 56Edge Full support ≤79Firefox Full support 62IE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support 62Opera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
message eventChrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari Full support YesWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS Full support YesSamsung Internet Android Full support 6.0
negotiated
Experimental
Chrome Full support 56Edge Full support ≤79Firefox Full support 68IE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support 68Opera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
onbufferedamountlow
Experimental
Chrome Full support 57
Notes
Full support 57
Notes
Notes The default for rtcpMuxPolicy is require.
Edge Full support ≤79
Notes
Full support ≤79
Notes
Notes The default for rtcpMuxPolicy is require.
Firefox Full support YesIE No support NoOpera Full support 44
Notes
Full support 44
Notes
Notes The default for rtcpMuxPolicy is require.
Safari Full support YesWebView Android Full support 57
Notes
Full support 57
Notes
Notes The default for rtcpMuxPolicy is require.
Chrome Android Full support 57
Notes
Full support 57
Notes
Notes The default for rtcpMuxPolicy is require.
Firefox Android Full support YesOpera Android Full support 43
Notes
Full support 43
Notes
Notes The default for rtcpMuxPolicy is require.
Safari iOS No support NoSamsung Internet Android Full support 7.0
Notes
Full support 7.0
Notes
Notes The default for rtcpMuxPolicy is require.
onclose
Experimental
Chrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
onclosing
Experimental
Chrome Full support 81Edge Full support 81Firefox No support NoIE No support NoOpera Full support 68Safari No support NoWebView Android Full support 81Chrome Android Full support 81Firefox Android No support NoOpera Android ? Safari iOS No support NoSamsung Internet Android ?
onerror
Experimental
Chrome Full support 56Edge Full support ≤79Firefox No support NoIE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android No support NoOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
onmessage
Experimental
Chrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari Full support YesWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS Full support YesSamsung Internet Android Full support 6.0
onopen
Experimental
Chrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari Full support YesWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS Full support YesSamsung Internet Android Full support 6.0
open eventChrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari Full support YesWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS Full support YesSamsung Internet Android Full support 6.0
ordered
Experimental
Chrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
priorityChrome No support NoEdge No support NoFirefox ? IE No support NoOpera ? Safari ? WebView Android No support NoChrome Android No support NoFirefox Android ? Opera Android ? Safari iOS No support NoSamsung Internet Android No support No
protocol
Experimental
Chrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
readyState
Experimental
Chrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
reliable
Deprecated
Chrome Full support 56Edge Full support ≤79Firefox No support NoIE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android No support NoOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0
Support for sctp-sdp-21 formatChrome Full support 58Edge Full support ≤79Firefox Full support 63IE No support NoOpera ? Safari No support NoWebView Android Full support 58Chrome Android Full support 58Firefox Android Full support 63Opera Android ? Safari iOS No support NoSamsung Internet Android Full support 7.0
sendChrome Full support 56Edge Full support ≤79Firefox Full support YesIE No support NoOpera Full support 43Safari Full support YesWebView Android Full support 56Chrome Android Full support 56Firefox Android Full support YesOpera Android Full support 43Safari iOS Full support YesSamsung Internet Android Full support 6.0
stream
DeprecatedNon-standard
Chrome Full support 56Edge Full support ≤79Firefox No support NoIE No support NoOpera Full support 43Safari No support NoWebView Android Full support 56Chrome Android Full support 56Firefox Android No support NoOpera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 6.0

Legend

Full support
Full support
No support
No support
Compatibility unknown
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.
Deprecated. Not for use in new websites.
Deprecated. Not for use in new websites.
See implementation notes.
See implementation notes.
Uses a non-standard name.
Uses a non-standard name.

See also