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

The Clients interface provides access to Client objects. Access it via self.clients within a service worker.

Methods

Clients.get()
Returns a Promise for a Client matching a given id.
Clients.matchAll()
Returns a Promise for an array of Client objects. An options argument allows you to control the types of clients returned. 
Clients.openWindow()
Opens a new browser window for a given url and returns a Promise for the new WindowClient.
Clients.claim()
Allows an active service worker to set itself as the controller for all clients within its scope

Examples

The following example shows an existing chat window or creates a new one when the user clicks a notification.

addEventListener('notificationclick', event => {
  event.waitUntil(async function() {
    const allClients = await clients.matchAll({
      includeUncontrolled: true
    });

    let chatClient;

    // Let's see if we already have a chat window open:
    for (const client of allClients) {
      const url = new URL(client.url);

      if (url.pathname == '/chat/') {
        // Excellent, let's use it!
        client.focus();
        chatClient = client;
        break;
      }
    }

    // If we didn't find an existing chat window,
    // open a new one:
    if (!chatClient) {
      chatClient = await clients.openWindow('/chat/');
    }

    // Message the client:
    chatClient.postMessage("New chat messages!");
  }());
});

Specifications

Specification Status Comment
Service Workers
The definition of 'Clients' in that specification.
Working Draft 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 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 27Safari No support NoWebView Android Full support 40Chrome Android Full support 40Edge Mobile ? Firefox Android Full support 44Opera Android Full support 27Safari iOS No support NoSamsung Internet Android Full support 4.0
claim
Experimental
Chrome Full support 42Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 29Safari No support NoWebView Android Full support 42Chrome Android Full support 42Edge Mobile ? Firefox Android Full support 44Opera Android Full support 29Safari iOS No support NoSamsung Internet Android Full support 4.0
get
Experimental
Chrome Full support 51Edge ? Firefox Full support 45
Notes
Full support 45
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 38Safari No support NoWebView Android No support NoChrome Android Full support 51Edge Mobile ? Firefox Android Full support 45Opera Android Full support 38Safari iOS No support NoSamsung Internet Android Full support 5.0
matchAll
Experimental
Chrome Full support 47
Notes
Full support 47
Notes
Notes Client objects returned in most recent focus order.
Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).
Full support 54
Notes
Notes Client objects returned in most recent focus order.
IE No support NoOpera Full support 32Safari No support NoWebView Android Full support 47
Notes
Full support 47
Notes
Notes Client objects returned in most recent focus order.
Chrome Android Full support 47
Notes
Full support 47
Notes
Notes Client objects returned in most recent focus order.
Edge Mobile ? Firefox Android Full support 44
Full support 44
Full support 54
Notes
Notes Client objects returned in most recent focus order.
Opera Android Full support 32Safari iOS No support NoSamsung Internet Android Full support 4.0
openWindow
Experimental
Chrome Full support 40
Full support 40
Full support 42
Notes
Notes Can only open URLs on the same origin.
Full support 43
Notes
Notes Can open any URL.
Full support 51
Notes
Notes URLs may open inside an existing browsing context provided by a standalone web app
Edge ? Firefox Full support 45
Notes
Full support 45
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 38Safari No support NoWebView Android Full support 40
Full support 40
Full support 42
Notes
Notes Can only open URLs on the same origin.
Full support 43
Notes
Notes Can open any URL.
Full support 51
Notes
Notes URLs may open inside an existing browsing context provided by a standalone web app
Chrome Android Full support 40
Full support 40
Full support 42
Notes
Notes Can only open URLs on the same origin.
Full support 43
Notes
Notes Can open any URL.
Full support 51
Notes
Notes URLs may open inside an existing browsing context provided by a standalone web app
Edge Mobile ? Firefox Android Full support 45Opera Android Full support 38Safari iOS No support NoSamsung Internet Android Full support 4.0
Full support 4.0
Full support 5.0
Notes
Notes URLs may open inside an existing browsing context provided by a standalone web app

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.
See implementation notes.
See implementation notes.

See also

Document Tags and Contributors

Last updated by: fscholz,