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Answer
What is a Web App Manifest?
Short answer
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. Browsers read it to decide whether to offer the install prompt and what icon and name to show on the home screen.
By InstantPWA engineering·Reviewed July 25, 2026
Required fields
At minimum, Chromium checks for name or short_name, a 512x512 icon, start_url and a display value of standalone, fullscreen or minimal-ui.
How to link it
Add <link rel="manifest" href="/manifest.webmanifest"> to every page you want installable, and serve it with the correct MIME type.
iOS caveats
Safari reads the manifest for name and theme colour, but still requires a separate <link rel="apple-touch-icon"> for the home-screen icon.
Related
What is a PWA?
A PWA (Progressive Web App) is a regular website that meets three technical criteria — HTTPS, a Web App Manifest and a service worker — so browsers let visitors install it on their home screen. Once installed, it launches like a native app, works offline and can send push notifications.
Why is my PWA install prompt not showing?
Chrome shows the install prompt only when the site passes strict installability criteria: HTTPS, a valid manifest with name, icons and start_url, a registered service worker with a fetch handler, and the user has not previously dismissed the prompt. Any one of these missing is enough to block the prompt entirely.
How do you add a PWA to the home screen on Android?
On Android, open the site in Chrome, tap the three-dot menu, and choose "Install app" (or "Add to Home screen" on some versions). If the site meets installability criteria, Chrome may also show an automatic install banner or mini-infobar without you having to open the menu.
How do you add a PWA to the home screen on iPhone?
On iPhone or iPad, open the site in Safari, tap the Share icon, scroll down and tap "Add to Home Screen", then tap "Add". Safari never shows an automatic install banner — the install must always be initiated manually from the Share sheet, and it only works in Safari, not third-party browsers.
What is the app shell architecture?
The app-shell architecture separates a PWA into two parts: a minimal "shell" of static UI (navigation, layout, styles) that a service worker caches and loads instantly on repeat visits, and dynamic content fetched separately from the network. This makes the app feel instant even before data loads.