WebTransportBidirectionalStream: writable property

Baseline 2026 *

Newly available

Since March 2026, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.

* Some parts of this feature may have varying levels of support.

See full compatibility

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 writable read-only property of the WebTransportBidirectionalStream interface returns a WebTransportSendStream instance that can be used to write outgoing data.

Value

A WebTransportSendStream.

Examples

See the main WebTransportBidirectionalStream interface page.

Specifications

Specification
WebTransport # dom-webtransportbidirectionalstream-writable

Browser compatibility

	desktop					mobile							server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS	Deno
`writable`	Chrome – Full support Chrome 97 (Release date: 2022-01-04) footnote Full support	Edge – Full support Edge 97 (Release date: 2022-01-06) footnote Full support	Firefox – Full support Firefox 114 (Release date: 2023-06-06) footnote Full support	Opera – Full support Opera 83 (Release date: 2022-01-19) footnote Full support	Safari – Full support Safari 26.4 (Release date: 2026-03-24) footnote Full support	Chrome Android – Full support Chrome Android 97 (Release date: 2022-01-04) footnote Full support	Firefox for Android – Full support Firefox for Android 114 (Release date: 2023-06-06) footnote Full support	Opera Android – Full support Opera Android 68 (Release date: 2022-03-30) footnote Full support	Safari on iOS – Full support Safari on iOS 26.4 (Release date: 2026-03-24) footnote Full support	Samsung Internet – Full support Samsung Internet 18 (Release date: 2022-08-08) footnote Full support	WebView Android – Full support WebView Android 97 (Release date: 2022-01-04) footnote Full support	WebView on iOS – Full support WebView on iOS 26.4 (Release date: 2026-03-24) footnote Full support	Deno – No support Deno 2.2 (Release date: 2025-02-19) disabled disabled From version 2.2 users must explicitly set the `--unstable-net` runtime flag.
Returns `WebTransportSendStream` (earlier spec returned `WritableStream`)	Chrome – No support Chrome footnote No support	Edge – No support Edge footnote No support	Firefox – Full support Firefox 114 (Release date: 2023-06-06) footnote Full support	Opera – No support Opera footnote No support	Safari – Full support Safari 26.4 (Release date: 2026-03-24) footnote Full support	Chrome Android – No support Chrome Android footnote No support	Firefox for Android – Full support Firefox for Android 114 (Release date: 2023-06-06) footnote Full support	Opera Android – No support Opera Android footnote No support	Safari on iOS – Full support Safari on iOS 26.4 (Release date: 2026-03-24) footnote Full support	Samsung Internet – No support Samsung Internet footnote No support	WebView Android – No support WebView Android footnote No support	WebView on iOS – Full support WebView on iOS 26.4 (Release date: 2026-03-24) footnote Full support	Deno – No support Deno 2.2 (Release date: 2025-02-19) disabled disabled From version 2.2 users must explicitly set the `--unstable-net` runtime flag.

Tip: you can click/tap on a cell for more information.

Full support: Full support
No support: No support
: User must explicitly enable this feature.

WebTransportBidirectionalStream: writable property

Value

Examples

Specifications

Browser compatibility

Legend

See also