Progressive Web Apps (PWAs): The Complete Developer Guide

Progressive Web Apps combine the best of web and native applications. They're reliable, fast, and engaging while remaining accessible through a URL without app store installation.

Core PWA Features

Service Workers

Service workers are JavaScript files that run in the background, enabling offline functionality, background sync, and push notifications.

// service-worker.js — Cache-first strategy
const CACHE_NAME = 'mortex-v2';
const urlsToCache = [
  '/',
  '/styles/main.css',
  '/scripts/app.js',
  '/images/logo.svg',
];

self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME)
      .then(cache => cache.addAll(urlsToCache))
  );
});

self.addEventListener('fetch', (event) => {
  event.respondWith(
    caches.match(event.request)
      .then(response => {
        if (response) return response; // Cache hit
        return fetch(event.request)    // Network fallback
          .then(res => {
            const clone = res.clone();
            caches.open(CACHE_NAME)
              .then(cache => cache.put(event.request, clone));
            return res;
          });
      })
  );
});

PWA Success Stories

• 📱 Twitter Lite: 75% increase in tweets sent, 65% increase in pages per session
• 📌 Pinterest: 60% increase in core engagements, 44% increase in ad revenue
• ☕ Starbucks: 2x daily active users from web