Background Fetch API provides a service worker based download and upload mechanism which is persistent across service worker and browser restarts. The system will provide a developer-controllable interface to schedule, query, pause, and cancel background downloads and uploads. After a scheduled fetch completes, the system will notify the developer of the outcome of the operation. In-progress fetches will be visible to users in a notification.
Docs: https://developers.google.com/web/updates/2018/12/background-fetch https://github.com/WICG/background-fetch/blob/master/README.md