Proposal: Periodic Background Sync

Periodic Background Sync is an extension of Background Sync. It enables websites to register tasks to be run in a service worker at periodic intervals with network connectivity. This will allow offline-first web apps to periodically update state, and will enable periodic content producers like news sites to push content to users’ devices periodically.

At present, sites can achieve this using Push messages, but need to set up a server for that.


There’s an explainer at

There’s an intent to implement for Chromium. This will help guide the design of the spec and API. We also plan to conduct an origin trial to assess API usability and make changes as a result.


An Intent to Experiment is now out for Periodic Background Sync!

The explainer has now moved to the WICG repository here:

We’re spinning up a new WICG repository for Periodic Background Sync.

The spec (current location: and the explainer (current location: will redirect to the new location, which I will also post here once available.

We (Microsoft) are interested in discussing and implementing this proposal. We support spinning up a separate repository for this feature on GitHub.

Belatedly, I’ve set up a dedicated repo: