Progressive Web Apps: a native-like experience from the web

PWAs combine the reach of the web with the capabilities of native apps — offline support, push notifications, home screen installation. Google defines a new standard.

Web vs native: a false dichotomy¶

The traditional view pits the web against native applications. The web has reach (URLs, no installation), native has capabilities (offline, notifications, hardware access). PWAs promise both.

Google defines PWAs as web applications that are:

• Reliable — work offline or on a slow connection
• Fast — instant response to interaction
• Engaging — push notifications, fullscreen, home screen icon

Service Workers: the foundation of PWA¶

A Service Worker is a JavaScript proxy between the app and the network:

// sw.js - Service Worker
self.addEventListener('install', function(event) {
  event.waitUntil(
    caches.open('v1').then(function(cache) {
      return cache.addAll([
        '/',
        '/css/app.css',
        '/js/app.js',
        '/offline.html'
      ]);
    })
  );
});

self.addEventListener('fetch', function(event) {
  event.respondWith(
    caches.match(event.request).then(function(response) {
      return response || fetch(event.request);
    })
  );
});

The Service Worker caches assets on install and serves them from the cache — the app works offline.

Web App Manifest and installation¶

The Web App Manifest is a JSON file describing the application:

{
  "name": "CORE Systems App",
  "short_name": "CORE",
  "start_url": "/",
  "display": "standalone",
  "background_color": "#040c0f",
  "theme_color": "#00d4ff",
  "icons": [
    { "src": "/icon-192.png", "sizes": "192x192", "type": "image/png" },
    { "src": "/icon-512.png", "sizes": "512x512", "type": "image/png" }
  ]
}

Chrome on Android shows an Add to Home Screen banner — the user installs the web application like a native app, without the app store.

Push notifications and the future¶

The Push API allows sending notifications even when the app is closed — a key feature for engagement.

Current support status:

• Chrome/Android — full PWA support
• Firefox — Service Workers and push notifications
• Safari/iOS — limited support (no push notifications)
• Edge — in progress

Safari is the biggest obstacle to mass PWA adoption. Apple has an economic interest in keeping the App Store as the only distribution channel.

Conclusion: the future of app distribution¶

PWAs have the potential to change the way users get applications. For businesses this means one codebase, no app store fees and instant updates. Watch Safari support — that will decide the success of PWA.