← Communication & Background
WebTransport
Probing…WebTransport is a web platform capability in the Communication & Background category. Low-latency client-server messaging over HTTP/3. Supported in Chromium 97+, Firefox 114+, and Safari 26.4+. Requires a secure context (HTTPS or localhost).
Secure context
Try it
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Code
const transport = new WebTransport('https://echo.webtransport.day')
await transport.ready
const stream = await transport.createBidirectionalStream()
const writer = stream.writable.getWriter()
await writer.write(new TextEncoder().encode('hello'))
await writer.close()
const reader = stream.readable.getReader()
const { value } = await reader.read()
console.log(new TextDecoder().decode(value))Browser support
Chromium
97
Firefox
114
Safari
26.4
Frequently asked questions
Which browsers support WebTransport?
Supported in Chromium 97+, Firefox 114+, and Safari 26.4+.
Does WebTransport require HTTPS?
Yes. WebTransport needs a secure context, so it only works over HTTPS (or on localhost during development).
What is WebTransport used for?
Low-latency client-server messaging over HTTP/3.
Can I try WebTransport in my browser?
Yes. shwcs.net runs a live WebTransport demo that probes your current browser and lets you try the API. Everything runs locally — nothing is sent anywhere.