WebTransport support

WebTransport transmits data between a client and a server over HTTP/3, offering reliable transport via streams and unreliable, UDP-like transport via datagrams over a single connection.

Browser & ecosystem support

• Legend
• Yes
• Partial
• Flag
• No
• Unknown

Browser / Platform	Support	Versions	Confidence	Source	Notes
Chrome (Desktop)	Yes	97	high	source	—
Chrome (Android)	Yes	97	high	source	1
Edge (Desktop)	Yes	97	high	source	2
Firefox (Desktop)	Yes	114	high	source	—
Firefox (Android)	Yes	114	high	source	3
Safari (macOS)	Yes	26.4	high	source	—
Safari (iOS)	Yes	26.4	high	source	4
Samsung Internet	Yes	18.0	high	source	5
WebView (Android)	Yes	97	high	source	6

1. Derived by browser-compat-data mirroring from Chrome.
2. Derived by browser-compat-data mirroring from Chrome.
3. Derived by browser-compat-data mirroring from Firefox.
4. Derived by browser-compat-data mirroring from Safari.
5. Derived by browser-compat-data mirroring from Chrome Android.
6. Derived by browser-compat-data mirroring from Chrome Android.

Source data: /compatibility/webtransport.json · Global usage: 93 % (StatCounter 2026-05)

Source: spec · MDN · Last verified 2026-10-03 · Confidence: high (computed from sources)

How to use it

Pass an https server URL to the WebTransport() constructor, then await the ready promise before using the connection:

async function connect(url) {
  const transport = new WebTransport(url);
  await transport.ready;
  return transport;
}

How to detect it at runtime

Check for WebTransport on window before constructing one. When it is absent, fall back to a WebSocket connection instead:

function openConnection(httpsUrl, wssUrl) {
  if ('WebTransport' in window) {
    return new WebTransport(httpsUrl);
  }
  return new WebSocket(wssUrl);
}

Practical checklist

• The URL passed to the constructor must use the https scheme.
• Datagrams (via the datagrams property) are unreliable and unordered; use them only for data where losing or reordering a message is acceptable, such as regular game-state updates.
• Use createBidirectionalStream() or createUnidirectionalStream() when delivery and order must be guaranteed.
• Safari did not ship WebTransport until Safari 26.4, closing a years-long gap where the API was effectively Chromium- and Firefox-only — do not assume it is universally available without checking the table above.

Where to go next

• Periodic Background Sync
• WebCodecs

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