⏰ Periodic Background Sync

What is Periodic Background Sync?

The Periodic Background Sync API allows a service worker to run tasks at periodic intervals, even when the user isn't actively using the page. Unlike regular Background Sync (which fires once when connectivity returns), periodic sync fires repeatedly on a schedule.

Use cases: Syncing news feed, updating cached data, checking for new content, etc.

⚠️ Browser Support & Requirements

Chrome/Edge only — Not supported in Firefox or Safari
The site must be installed as a PWA or have high engagement score
The browser decides the actual interval based on site engagement (your requested interval is a minimum, not guaranteed)
Permission can be checked/managed at chrome://settings/content/periodicBackgroundSync

Live Demo

Status: Ready

Choose sync interval:

1 minute
(testing only)

1 hour
(minimum practical)

12 hours
(good for news)

24 hours
(daily updates)

Event Log

🔧 DevTools: Inspecting Periodic Sync

Open DevTools → Application panel
Expand Background services → click Periodic Background Sync
Click the record button (⏺) to start recording
Register a periodic sync and observe the events
You can also see the registered tags in the Service Workers section
Tip: You can manually trigger a periodicsync event from the Service Workers panel by entering the tag name and clicking "Periodic Sync"

📝 Practice Exercise

Start recording periodic sync events in the Application panel
Register a periodic sync with a 1-minute interval
Check the registered tags — is your sync registered?
Go to Application → Service Workers and manually trigger the periodicsync event
Unregister the sync and verify the tags are cleared
Check the permission status — is periodic sync allowed for this site?