Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

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

Note: This feature is available in Web Workers.

The WebTransportError interface of the WebTransport API represents an error related to the API, which can arise from server errors, network connection problems, or client-initiated abort operations (for example, arising from a WritableStream.abort() call).

DOMException WebTransportError



Creates a new WebTransportError object instance.

Instance properties

Inherits properties from its parent, DOMException.

source Read only

Returns an enumerated value indicating the source of the error—can be either stream or session.

streamErrorCode Read only

Returns a number in the range 0-255 indicating the application protocol error code for this error, or null if one is not available.


const url = "notaurl";

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

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

    // ...
  } catch (error) {
    const msg = `Transport initialization failed.
                 Reason: ${error.message}.
                 Source: ${error.source}.
                 Error code: ${error.streamErrorCode}.`;


# webtransporterror

Browser compatibility

BCD tables only load in the browser

See also