/Web APIs


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

The PeriodicSyncEvent interface of the Web Periodic Background Synchronization API provides a way to run tasks in the service worker with network connectivity.

An instance of this event is passed to the periodicsync handler. This happens periodically, at an interval greater than or equal to that set in the PeriodicSyncManager.register() method. Other implementation-specific factors such as the user's engagement with the site decide the actual interval.

Event ExtendableEvent PeriodicSyncEvent


PeriodicSyncEvent.PeriodicSyncEvent() Experimental

Creates a new PeriodicSyncEvent object. This constructor is not typically used. The browser creates these objects itself and provides them to onperiodicsync callback.

Instance properties

PeriodicSyncEvent.tag Read only Experimental

Returns the developer-defined identifier for this PeriodicSyncEvent. Multiple tags can be used by the web app to run different periodic tasks at different frequencies.

Instance methods

Inherits methods from its parent ExtendableEvent.


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") {

fetchAndCacheLatestNews is a developer defined function.


Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
PeriodicSyncEvent 80 80 No No 67 No No 80 No 57 No 13.0
PeriodicSyncEvent 80 80 No No 67 No No 80 No 57 No 13.0
tag 80 80 No No 67 No No 80 No 57 No 13.0

See also

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