This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

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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".

When a binary message is received on the data channel, the resulting message event's MessageEvent.data property is an object of the type specified by the binaryType.


var type = aDataChannel.binaryType;

aDataChannel.binaryType = type; 


A DOMString that can have one of these values:

Received binary messages' contents will be contained in Blob objects.
Received binary messages' contents will be contained in ArrayBuffer objects.


This code configures a data channel to receive binary data in ArrayBuffer objects, and establishes a listener for message events which constructs a string representing the received data as a list of hexadecimal byte values.

var dc = peerConnection.createDataChannel("Binary");
dc.binaryType = "arraybuffer";

dc.onmessage = function(event) {
  let byteArray = new Uint8Array(event.data);
  let hexString = "";

  byteArray.forEach(function(byte) {
    hexString += byte.toString(16) + " ";


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

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes ?22 No Yes ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support2929 ?22 Yes No ?

See also

Document Tags and Contributors

 Contributors to this page: fscholz, jpmedley, Sheppy, kalitine, teoli
 Last updated by: fscholz,