RTCDataChannel: binaryType property

The property binaryType on the RTCDataChannel interface is a string which specifies the type of 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.


A string 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.

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

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

  byteArray.forEach((byte) => {
    hexString += `${byte.toString(16)} `;


WebRTC: Real-Time Communication in Browsers
# dom-datachannel-binarytype

Browser compatibility

BCD tables only load in the browser

See also