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

The ReadableStream interface of the Streams API represents a readable stream of byte data. The Fetch API offers a concrete instance of a ReadableStream through the body property of a Response object.

Constructor

ReadableStream()
Creates and returns a readable stream object from the given handlers.

Properties

ReadableStream.locked Read only
The locked getter returns whether or not the readable stream is locked to a reader.

Methods

ReadableStream.cancel()
Cancels the stream, signaling a loss of interest in the stream by a consumer. The supplied reason argument will be given to the underlying source, which may or may not use it.
ReadableStream.getReader()
Creates a reader and locks the stream to it. While the stream is locked, no other reader can be acquired until this one is released.
ReadableStream.pipeThrough()
Provides a chainable way of piping the current stream through a transform stream or any other writable/readable pair.
ReadableStream.pipeTo()
Pipes the current ReadableStream to a given WritableStream and returns a promise that fulfills when the piping process completes successfully, or rejects if any errors were encountered.
ReadableStream.tee()
The tee method tees this readable stream, returning a two-element array containing the two resulting branches as new ReadableStream instances.

Examples

In the following example, an artifical Response is created to stream HTML fragments fetched from another resource to the browser.

It demonstrates the usage of a ReadableStream in combination with a Uint8Array.

fetch("https://www.example.org/").then((response) => {
  const reader = response.body.getReader();
  const stream = new ReadableStream({
    start(controller) {
      // The following function handles each data chunk
      function push() {
        // "done" is a Boolean and value a "Uint8Array"
        reader.read().then(({ done, value }) => {
          // Is there no more data to read?
          if (done) {
            // Tell the browser that we have finished sending data
            controller.close();
            return;
          }

          // Get the data and send it to the browser via the controller
          controller.enqueue(value);
          push();
        });
      };
      
      push();
    }
  });

  return new Response(stream, { headers: { "Content-Type": "text/html" } });
});

Specifications

Specification Status Comment
Streams
The definition of 'ReadableStream' in that specification.
Living Standard Initial definition

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic support
Experimental
Chrome Full support 43Edge Full support 16Firefox Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE No support NoOpera Full support 30Safari ? WebView Android Full support 43Chrome Android Full support 43Edge Mobile Full support 16Firefox Android Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 30Safari iOS ? Samsung Internet Android Full support 4.0
ReadableStream() constructor
Experimental
Chrome Full support 43Edge Full support 16Firefox Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE No support NoOpera Full support 30Safari ? WebView Android Full support 43Chrome Android Full support 43Edge Mobile Full support 16Firefox Android Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 30Safari iOS ? Samsung Internet Android Full support 4.0
locked
Experimental
Chrome Full support 43Edge Full support 16Firefox Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE No support NoOpera Full support 30Safari ? WebView Android Full support 43Chrome Android Full support 43Edge Mobile Full support 16Firefox Android Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 30Safari iOS ? Samsung Internet Android Full support 4.0
cancel
Experimental
Chrome Full support 43Edge Full support 16Firefox Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE No support NoOpera Full support 30Safari ? WebView Android Full support 43Chrome Android Full support 43Edge Mobile Full support 16Firefox Android Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 30Safari iOS ? Samsung Internet Android Full support 4.0
getReader
Experimental
Chrome Full support 43Edge Full support 16Firefox Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE No support NoOpera Full support 30Safari ? WebView Android Full support 43Chrome Android Full support 43Edge Mobile Full support 16Firefox Android Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 30Safari iOS ? Samsung Internet Android Full support 4.0
pipeThrough
Experimental
Chrome Full support 59Edge ? Firefox Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE No support NoOpera Full support 46Safari ? WebView Android Full support 59Chrome Android Full support 59Edge Mobile ? Firefox Android Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 46Safari iOS ? Samsung Internet Android Full support 7.0
pipeTo
Experimental
Chrome Full support 59Edge ? Firefox Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE No support NoOpera Full support 46Safari ? WebView Android Full support 59Chrome Android Full support 59Edge Mobile ? Firefox Android Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 46Safari iOS ? Samsung Internet Android Full support 7.0
tee
Experimental
Chrome Full support 43Edge Full support 16Firefox Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE No support NoOpera Full support 30Safari ? WebView Android Full support 43Chrome Android Full support 43Edge Mobile Full support 16Firefox Android Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 30Safari iOS ? Samsung Internet Android Full support 4.0

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
User must explicitly enable this feature.
User must explicitly enable this feature.

Document Tags and Contributors

Last updated by: jcsahnwaldt,