Web/API/Web Periodic Background Synchronization API

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The Web Periodic Background Synchronization API provides a way to register tasks to be run in a service worker at periodic intervals with network connectivity. These tasks are referred to as periodic background sync requests.

Web Periodic Background Synchronization Concepts and Usage

The Periodic Background Sync API allows web applications to alert their service worker to make any updates, at a periodic time interval. Uses may include fetching latest content whilst a device is connected to wifi, or allowing background updates to an application.

The minimum time interval is set when the API is invoked; however the user agent might also take into account other factors which affect when the service worker receives the event. For instance previous website engagement, or connection to a known network.

The PeriodicSyncManager interface is available through ServiceWorkerRegistration.periodicSync. A unique tag identifier is set to 'name' the sync event, which can then be listened for within the ServiceWorker script. Once the event is received you can then run any functionality available, such as updating caches or fetching new resources.

As this API relies on service workers, functionality provided by this API is only available in a secure context.

At the time of writing, the Web Periodic Background Synchronization API is only available through an installed Progressive Web App

Web Periodic Background Synchronization Interfaces

PeriodicSyncManager: Registers tasks to be run in a service worker at periodic intervals with network connectivity. These tasks are referred to as periodic background sync requests.
PeriodicSyncEvent: Represents a synchronization event, sent to the global scope of a ServiceWorker. It provides a way to run tasks in the service worker with network connectivity.

Service Worker Additions

The following additions to the Service Worker API are specified in the Periodic Background Sync specification to provide an entry point for using Periodic Background Sync.

ServiceWorkerRegistration.periodicSync Read only: Returns a reference to the PeriodicSyncManager interface for registering tasks to run at specific intervals.
ServiceWorkerGlobalScope.onperiodicsync: An event handler fired whenever a periodicsync event occurs. This happens at timed intervals, that are specified when registering a PeriodicSyncManager.

Examples

The following examples show how to use the interface.

Requesting a Periodic Background Sync

The following asynchronous function registers a periodic background sync at a minimum interval of one day from a browsing context:

async function registerPeriodicNewsCheck() {
  const registration = await navigator.serviceWorker.ready;
  try {
    await registration.periodicSync.register('fetch-news', {
      minInterval: 24 * 60 * 60 * 1000,
    });
  } catch {
    console.log('Periodic Sync could not be registered!');
  }
}

Verifying a Background Periodic Sync by Tag

This code checks to see if a Periodic Background Sync task with a given tag is registered.

navigator.serviceWorker.ready.then(registration => {
  registration.periodicSync.getTags().then(tags => {
    if (tags.includes('get-latest-news'))
      skipDownloadingLatestNewsOnPageLoad();
  });  
});

Removing a Periodic Background Sync Task

The following code removes a Periodic Background Sync task to stop articles syncing in the background.

navigator.serviceWorker.ready.then(registration => {
  registration.periodicSync.unregister('get-latest-news');
});

Listening for a Periodic Background Sync within a Service Worker

The following example shows how to respond to a periodic sync event in the service worker.

self.addEventListener('periodicsync', event => {
  if (event.tag == 'get-latest-news') {
    event.waitUntil(fetchAndCacheLatestNews());
  }
});

Specifications

Specification	Status	Comment
Web Periodic Background Synchronization	Working Draft	Initial definition.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`PeriodicSyncManager` Experimental'Non-standard'	Chrome Full support 80	Edge Full support 80	Firefox No support No	IE No support No	Opera Full support 67	Safari No support No	WebView Android Full support 80	Chrome Android Full support 80	Firefox Android No support No	Opera Android Full support 57	Safari iOS No support No	Samsung Internet Android Full support 13.0
`getTags` Experimental'Non-standard'	Chrome Full support 80	Edge Full support 80	Firefox No support No	IE No support No	Opera Full support 67	Safari No support No	WebView Android Full support 80	Chrome Android Full support 80	Firefox Android No support No	Opera Android Full support 57	Safari iOS No support No	Samsung Internet Android Full support 13.0
`register` Experimental'Non-standard'	Chrome Full support 80	Edge Full support 80	Firefox No support No	IE No support No	Opera Full support 67	Safari No support No	WebView Android Full support 80	Chrome Android Full support 80	Firefox Android No support No	Opera Android Full support 57	Safari iOS No support No	Samsung Internet Android Full support 13.0
`unregister` Experimental'Non-standard'	Chrome Full support 80	Edge Full support 80	Firefox No support No	IE No support No	Opera Full support 67	Safari No support No	WebView Android Full support 80	Chrome Android Full support 80	Firefox Android No support No	Opera Android Full support 57	Safari iOS No support No	Samsung Internet Android Full support 13.0

Legend

Full support: Full support
No support: No support
Experimental. Expect behavior to change in the future.': Experimental. Expect behavior to change in the future.
Non-standard. Expect poor cross-browser support.': Non-standard. Expect poor cross-browser support.