What Is a Progressive Web App? A Beginner’s Tutorial
A progressive web app (PWA) is a website that behaves like a native mobile app. It loads in a browser but can be installed on a device’s home screen, work offline, send push notifications, and run full-screen without browser chrome. Behind the scenes, it’s still HTML, CSS, and JavaScript.
The core idea is progressive enhancement: every visitor gets a working website, while capable browsers unlock app-like features. No app store review, no separate codebase.
Three Technologies Behind Every PWA
- Service worker: a background script that caches assets and intercepts network requests, enabling offline mode and fast repeat visits.
- Web app manifest: a JSON file defining the app name, icons, theme colour, and display mode so it launches like a native app.
- HTTPS: required for security, since service workers can control network traffic.
Why Teams Choose PWAs
- One codebase covers desktop, Android, and iOS.
- Users skip app stores — installation is one tap in the browser.
- Updates deploy instantly to everyone.
- Smaller than most native apps, which improves retention.
Where PWAs Fall Short
iOS support is improving but still lags. Access to some hardware APIs, background sync, and push notifications remains limited compared to native. Heavy 3D games or apps needing deep device integration usually still need native code.
Getting Started
Build a normal responsive site, add a manifest file, register a service worker, and test it with Lighthouse in Chrome DevTools. If it installs and works offline, you have shipped a PWA.
