Notifications

Notifications are how an installed PWA re-engages users after they leave: a server pushes a message, the service worker wakes to handle it, and a system notification appears. The power comes with a strict permission model — ask in context, on a gesture — and platform rules, notably that iOS requires the PWA to be installed to the Home Screen first.

These entries cover the push pipeline, the permission model, and periodic background updates.

In this section

Web PushThe Push API + VAPID subscriptions, the permission model, the service worker push/notificationclick events, and the iOS requirement.

The notification permission modelHow Notification.requestPermission() works, the three permission states, and the user-gesture requirement.

Periodic background sync for updatesHow the Periodic Background Sync API refreshes content in the background, how that differs from a push notification, and the install/engagement gate.

← Back to the Reference overview.