PWAs combine the best of web and native apps. Discover how to build fast, reliable, engaging experiences that work offline and install like apps.
What Makes PWAs Different
Progressive Web Apps blur the line between websites and native applications. They load like regular web pages but offer app-like experiences: offline functionality, push notifications, home screen installation, and fast, smooth performance.
Unlike native apps that require separate codebases for iOS and Android, PWAs are built once with web technologies and work everywhere. They're discoverable via search engines, shareable via URLs, and don't require app store approval or downloads.
Core PWA Technologies
Three key technologies enable PWA functionality, working together to create app-like experiences on the web.
Service Workers: Scripts that run in the background, enabling offline functionality and push notifications
Web App Manifest: JSON file defining how the app appears when installed on devices
HTTPS: Secure connections required for service worker functionality
Cache API: Storing assets locally for instant loads and offline access
Background Sync: Deferring actions until stable connectivity is available
Web Push Notifications: Re-engaging users with timely, relevant updates
Building Your First PWA
Start with a fast, responsive website. Add a web app manifest defining your app's name, icons, colors, and display mode. Implement a service worker to cache critical assets and enable offline functionality.
Focus on the "app shell" architecture: cache the UI shell separately from content. This allows instant loading of the interface even offline, with content loading when connectivity is available. Test thoroughly across devices and network conditions.
"PWAs democratize app development—anyone who can build a website can now create app experiences that rival native applications."
Performance and Optimization
PWAs must be fast. Use lazy loading, code splitting, and efficient caching strategies. Optimize images and minimize JavaScript. Aim for sub-3-second load times even on slow connections.
Monitor real user metrics: Time to Interactive, First Contentful Paint, and Largest Contentful Paint. Use Lighthouse to audit PWA compliance and performance. Remember: a PWA is only as good as its worst performance on a user's actual device and network.
