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

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.

See Buffering in Using WebRTC data channels to learn more about how to work with the data channel buffer.


RTCDataChannel.onbufferedamountlow = function;


A function which the browser will call to handle the bufferedamountlow event. This function receives as its only input parameter a simple Event object representing the event which has occurred.


This example responds to the bufferedamountlow event by fetching up to 64kB of a file represented by an object source and calling RTCDataChannel.send() to queue up the retrieved data for sending on the data channel.

pc = new RTCPeerConnection();
dc = pc.createDataChannel("SendFile");

/* ... */

pc.onbufferedamountlow = function() {
  if (source.position <= source.length) {


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

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support571 ? ? ?441 ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support571571 ? ?441 ?7.0

1. The default for rtcpMuxPolicy is require.

Document Tags and Contributors

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