PWA glossarythe terms, defined
Plain-English definitions for every term you'll meet building a PWA.
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.
Read definitionWeb App Manifest
A Web App Manifest is a JSON file (usually manifest.webmanifest) that declares your app's name, icons, start URL, theme colour and display mode. The browser reads it to render the install prompt and the home-screen icon.
Read definitionbeforeinstallprompt
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.
Read definitionWeb push
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.
Read definitionStandalone 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.
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