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WebTransport: WebTransport() constructor

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

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The WebTransport() constructor creates a new WebTransport object instance.

Note: This feature is available in Web Workers

Syntax

new WebTransport(url, options)

Parameters

url

A string representing the URL of the HTTP/3 server to connect to. The scheme needs to be HTTPS, and the port number needs to be explicitly specified.

options Optional

An object containing the following properties:

serverCertificateHashes Optional: An array of WebTransportHash objects. If specified, it allows the website to connect to a server by authenticating the certificate against the expected certificate hash instead of using the Web public key infrastructure (PKI). This feature allows Web developers to connect to WebTransport servers that would normally find obtaining a publicly trusted certificate challenging, such as hosts that are not publicly routable, or ephemeral hosts like virtual machines.

WebTransportHash objects contain two properties:

algorithm: A string representing the algorithm to use to verify the hash. Any hash using an unknown algorithm will be ignored.
value: A BufferSource representing the hash value.

Exceptions

NotSupportedError DOMException: Thrown if serverCertificateHashes is specified but the transport protocol does not support this feature.
SyntaxError DOMException: Thrown if the specified url is invalid, if the scheme is not HTTPS, or if the URL includes a fragment.

Examples

const url = "https://example.com:4999/wt";

async function initTransport(url) {
  // Initialize transport connection
  const transport = new WebTransport(url);

  // The connection can be used once ready fulfills
  await transport.ready;

  // ...
}

// ...

async function closeTransport(transport) {
  // Respond to connection closing
  try {
    await transport.closed;
    console.log(`The HTTP/3 connection to ${url} closed gracefully.`);
  } catch (error) {
    console.error(`The HTTP/3 connection to ${url} closed due to ${error}.`);
  }
}

Specifications

Specification
WebTransport # dom-webtransport-webtransport

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`WebTransport`	97	97	No	No	83	No	97	97	No	68	No	18.0
`serverCertificateHashes`	100	100	No	No	86	No	100	100	No	69	No	19.0