WebTransport is a protocol framework that enables clients constrained by the Web security model to communicate with a remote server using a secure multiplexed transport.


Currently, Web application developers have two APIs for bidirectional communications with a remote server: WebSockets and RTCDataChannel. WebSockets are TCP-based, thus having all of the drawbacks of TCP that make it a poor fit for latency sensitive applications (head of line blocking, lack of support for unreliable data transport). RTCDataChannel is based on SCTP, which does not have these drawbacks; however, it is designed to be used in a peer-to-peer context, which caused its use in client-server settings to be fairly low. WebTransport provides a client-server API that supports bidirectional transfer of both unreliable and reliable data, using UDP-like datagrams and cancellable streams.


Editor's draft

Status in Chromium


Origin trial (tracking bug) in:

  • Chrome for desktop release 91
  • Chrome for Android release 91

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

  • Worth prototyping
  • Positive
  • No signal
  • Positive


Intent to Prototype url

Intent to Prototype thread

Search tags

webtransport, udp websocket,

Last updated on 2021-07-17