Definition

Web push

Short definition

Web push is a W3C standard that lets a website deliver push notifications to a user's device via the browser's push service, even when the site is closed. Delivery requires a service worker and explicit user permission.

Reviewed July 8, 2026

Web push uses VAPID keys for identification and a PushSubscription object stored per user. Payloads are encrypted end-to-end between sender and browser.

iOS Safari 16.4+ supports web push, but only for PWAs installed to the home screen. On the open web (a tab), pushes are silently dropped on iOS.

Chromium and Firefox support web push in tabs, in installed PWAs and even in incognito with permission.

Related terms

Service worker

A service worker is a JavaScript file the browser runs in the background, separate from the page. It intercepts network requests, caches responses so the site works offline, and receives web-push events so the site can notify the user when it is closed.

beforeinstallprompt

beforeinstallprompt is a window event Chromium browsers fire when a site meets the PWA install criteria. Capturing the event and calling prompt() later lets you show the install dialog at a moment of your choosing instead of at page load.

Standalone display mode

Standalone is a value of the display field in a Web App Manifest. It tells the browser to launch the PWA in its own window with no address bar or tabs, so it looks and behaves like a native app. It is the most common display mode for installable PWAs.

name (manifest field)

name is a required-in-practice string field in the Web App Manifest that gives the full, human-readable title of the app. Browsers show it on the install dialog, the splash screen and in the OS app switcher. It can be up to 45 characters before some UIs truncate it.

short_name (manifest field)

short_name is an optional manifest string, typically under 12 characters, used wherever screen space is limited — the home-screen label, the app switcher, or a launcher grid. When short_name is absent the browser falls back to the full name field, which may get truncated with an ellipsis.

start_url (manifest field)

start_url is the manifest field that sets the exact URL loaded when a user taps the installed app icon. It is resolved relative to the manifest URL, so "start_url": "/?source=pwa" launches the origin root with a query string you can use to distinguish installed-app sessions from browser-tab sessions in analytics.