📘 Progressive Web App (PWA)
🔹 What is a PWA?
A Progressive Web App (PWA) is a web application that behaves like a native mobile app.
It runs in the browser but gives users an experience similar to installing a real app — complete with offline access, push notifications, home screen icon, and fast performance.
🔹 Key Characteristics of a PWA:
| Feature | Description |
|---|---|
| Installable | Can be added to home screen (like an app) |
| Offline Support | Works without internet using a Service Worker |
| Responsive | Works on all screen sizes — mobile, tablet, desktop |
| Fast Loading | Uses caching to improve speed |
| App-like | Fullscreen UI, smooth navigation, no address bar |
| Secure | Always served over HTTPS |
🔹 How Does It Work?
To qualify as a PWA, your site needs 3 things:
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HTTPS — ensures all communication is secure
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Web App Manifest — a JSON file that defines the app’s name, icon, theme color, etc.
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Service Worker — a background script that handles offline caching, push notifications, etc.
🔹 PWA Lifecycle (Simplified):
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User visits the website
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Browser detects it’s a PWA → shows “Add to Home Screen”
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On install:
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It gets a home screen icon
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Loads like a standalone app (without address bar)
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Can work offline, thanks to the service worker
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On updates, the service worker fetches new versions in the background.
🔹 Common Use Cases:
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News sites (e.g., Twitter Lite)
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E-commerce platforms
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Travel apps
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Blogs and content platforms
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Any web app targeting mobile users with limited internet
🔹 Advantages:
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No need to go through app stores
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Smaller than native apps
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Cross-platform
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Offline support
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Auto updates
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Can send push notifications
🔹 Limitations:
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Not all device features are available (e.g., Bluetooth, advanced sensors)
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Browser support varies (though most modern browsers support PWAs)