ServiceWorkerGlobalScope: backgroundfetchfail event

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

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

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

Note: This feature is only available in Service Workers.

The backgroundfetchfail event of the ServiceWorkerGlobalScope interface is fired when a background fetch operation has failed: that is, when at least one network request in the fetch has failed to complete successfully.

This event is not cancelable and does not bubble.


Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("backgroundfetchfail", (event) => {});

onbackgroundfetchfail = (event) => {};

Event type

Event properties

Inherits properties from its parent, BackgroundFetchEvent.


Updates the UI of the element that the browser displays to show the progress of the fetch operation.


When a background fetch operation fails (meaning that at least one of the individual network requests has not completed successfully), the browser starts the service worker, if necessary, and fires the backgroundfetchfail event in the service worker's global scope.

In the background fetch API, the browser shows a UI element to the user to indicate the progress of the operation. In the backgroundfetchfail handler, the service worker can update that UI to show that the operation has failed. To do this, the handler calls the event's updateUI() method, passing in a new title and/or icons.

In the handler for this backgroundfetchfail, the service worker can also clean up any related data for the operation. It can also retrieve and store any successful responses (for example, using the Cache API). To access the response data, the service worker uses the event's registration property.


Updating UI

This event handler updates the UI to let the user know that the operation failed.

addEventListener("backgroundfetchfail", (event) => {
  event.updateUI({ title: "Could not complete download" });


Background Fetch
# dom-serviceworkerglobalscope-onbackgroundfetchfail

Browser compatibility

BCD tables only load in the browser

See also