Transforming Your Web App into an Immersive App-Like Experience with Progressive Web Apps

Progressive web applications take traditional websites and transform them to feel like full-fledged mobile and desktop apps. By harnessing modern web capabilities and techniques, you can enhance engagement, loyalty and interactivity.

In this comprehensive guide, we will explore:

  • What exactly makes progressive web apps special
  • Step-by-step instructions for converting an existing web app
  • How to enable push notifications with Firebase Cloud Messaging
  • Optimization best practices to delight your users

Converting to a progressive web app allows you to reuse website code while providing functionality previously only seen in native apps. The end result is an immersive app-like experience on the open web.

The Rise of Progressive Web Apps

Progressive web apps aim to combine the reach and accessibility of websites with the functionality of native applications.

Some key statistics around adoption:

  • 56% of developers now use or plan to use PWAs, per a 2022 Stack Overflow survey
  • Pinterest saw a 150% increase in ad revenue after switching to a PWA
  • Tinder observed a 98% increase in swipe rates upon shifting to a progressive app
  • Forbes found that their PWA conversion rate from visitor to subscriber was 2x their website
  • Alaska Airlines saw 55% more mobile engagement with their progressive web app

What exactly causes this increase in engagement and revenue for PWAs compared to normal websites?

Key Differentiators of Progressive Web Apps

Unlike basic websites, progressive web apps provide:

📱 App-style experience – With immersive interfaces, smooth scrolling and animations

💾 Offline functionality – Leveraging service workers and caching to support unreliable networks

📬 Push notifications – Allowing users to opt into timely updates and re-engagement

🔔 Home screen icons – Enabling users to install the PWA like a native app for quick access

🎯 Cross-platform versatility – Using web standards for wide device and browser compatibility

☕️Background processing – Enabling features like GPS tracking without needing the app visibly open

These enhanced capabilities fuel higher engagement from users who enjoy app-like experiences from your website.

Now let‘s see how you can unlock these features by converting your web app into an installable PWA next.

Prerequisites Before Converting to a PWA

Before embarking on turning your website into a progressive web app, some key requirements to fulfill first:

🔒 HTTPS protocol – PWAs require secure HTTPS connections to prevent network tampering and enable service workers. Prioritize upgrading your site to support this first.

😎 Responsive mobile design – Ensure your website works flawlessly across phones, tablets and desktop sizes with a mobile-friendly responsive layout.

💻 Existing web app to build from – Have a website built with HTML, JavaScript and CSS already before aiming to convert to an app experience. Don‘t start from zero.

Fulfilling these prerequisites establishes a foundation to then progressively enhance into an advanced web app.

Step 1 – Design App Icons and Splash Screens

Unlike normal websites, progressive web apps feature specially sized icons and splash screens that make them feel more like native apps once users install them on home screens.

Key assets to design include:

🖼️ App icons – Create square png app icons like 192×192 and 512×512 sizes. Ensure crisp, consistent iconography.

🏞️ Splash screens – Build custom splash screens for quick load states when users open your PWA. Tailor to various device sizes like desktop and mobile.

Properly sized icons enable that app-like experience when users install your PWA web app alongside their device‘s existing native apps.

Learn more about ideal icon sizes and splashes for PWAs.

Step 2 – Define a Web Manifest

A web app manifest is a JSON file that specifies key metadata to determine how your web app functions as a PWA.

Here are some key things it defines:

  • Name, short name and description
  • Start URL that opens when launched
  • Theme color like the mobile address bar
  • Background color for splash screens
  • Icons used for home screen install prompts
  • Screen orientations allowed
  • Whether fullscreen functionality is enabled

For example, a simple manifest file may look like:

{
  "short_name": "App Name",
  "name": "App Name",
  "icons": [{
    "src": "icon-192.png",
    "type": "image/png",
    "sizes": "192x192"  
  }],
  "start_url": "/",
  "background_color": "#ffffff",
  "display": "fullscreen",
  "orientation": "portrait",
  "theme_color": "#000000"   
} 

Reference this web app manifest in your main index.html using:

<link rel="manifest" href="/manifest.json">  

Providing this structured metadata allows the browser and operating systems to recognize your PWA‘s purpose.

Step 3 – Register a Service Worker

The service worker lies at the heart of any progressive web app. This JavaScript runs separately from the main browser thread to enable capabilities like offline support, background syncing and push notifications.

Here is some simple code to register a service worker service-worker.js from your web pages:

// Register Service Worker
if (‘serviceWorker‘ in navigator) {
  window.addEventListener(‘load‘, () => {
    navigator.serviceWorker.register(‘/service-worker.js‘); 
  });
}

This first checks if service workers are supported, and if so registers service-worker.js to handle work in the background.

Inside service-worker.js is the logic that will manage offline caching, respond to push notifications, and sync data in the background when needed.

To start, let‘s intercept fetch requests to lay the foundation:

// service-worker.js

self.addEventListener(‘fetch‘, (event) => {

  // Logic to handle requests later

});

As you build out your service worker capabilities later, you can leverage caching for offline use cases and enable advanced features.

Step 4 – Test Out Your Baseline PWA

With the fundamentals in place from a web manifest, service worker registration and icons defined, you can test out your barebones PWA:

  • 💻 Open the site in a PWA supported browser like Chrome
  • 📱 Check for the installability prompt in the address bar on mobile and "Add to desktop" on desktop browsers
  • 🏠 Add your web app to your mobile home screen or desktop
  • 🚀 Open your installed PWA and validate it loads correctly without a browser interface

While very baseline at this point, testing out these core PWA experiences now ensures the fundamentals work cross-browser before enhancing further.

Step 5 – Enable Offline Functionality

While the internet continues expanding, network reliability can still be spotty in areas. Progressive web apps should handle offline or intermittent connectivity via intelligent caching of key resources locally.

This enables users to continue interacting with your app offline once the initial application shell has been cached. The service worker handles implementing all offline caching logic using the Cache Storage browser API.

// Cache Shell Files
const CACHE = "pwabuilder-offline";

self.addEventListener("install", (event) => {
  event.waitUntil(
    caches.open(CACHE).then((cache) => {
      return cache.addAll([
        "/",
        "/index.html",
        "/styles/main.css",
        "/scripts/app.js"
      ]);
    })
  ); 
});

// Network Fallback
self.addEventListener(‘fetch‘, (event) => {
  event.respondWith(
    caches.match(event.request)
      .then((response) => { 
        return response || fetch(event.request)  
      })
  );
});

This caches the app shell like HTML/CSS/JavaScript to support offline functionality. The service worker fetches cached responses first, using the network as a fallback.

More advanced caching logics exist using versioning and cache expiration. But this demonstrates the main workings!

Step 6 – Enable Push Notifications

Push notifications entice users to return and interact with updates from your web app – even when it‘s not loaded in the browser yet.

Components needed on the client include:

  • Requesting permission – Get consent from users to send notifications first
  • Service worker – Manages receiving/displaying notifications
  • Subscribing – Register a push subscription and endpoint on the server to send notifications to later

Here is browser code to implement push notification permissions and subscriptions:

// After Service Worker Registration  

const publicVapidKey =  
  "BG3OxG0JSI5ZpvbdgIH6wOxORMcfVwg0YIofT6PUcSpmnnQmo7dXNFJbeqIDw6AtjQzThxwFBl6cg17bAMKUYEU";  

// Check for permission  
if (Notification.permission == ‘granted‘) {
  subscribeUser(); 
} else {   
  // Request permission
  Notification.requestPermission().then() => {  
    if (consent === ‘granted‘) {  
      subscribeUser();
    } 
  });    
}

// Subscribe method  
function subscribeUser() {
  navigator.serviceWorker.ready
    .then((reg) => {  
      // Check if existing subscription  
      if (subscription) {
        // Send subscription to server
      } else {
        // Subscribe and send to server 
      }
  }).catch((err) => {
      console.warn(‘Failed to subscribe for push‘, err);
  });  
} 

This handles client-side permissions, subscriptions and displays push notifications at the service worker layer.

The server-side code to trigger notifications differs by tech stack. Here is a Node.js example using web-push:

const webPush = require(‘web-push‘);
  webPush.setVapidDetails(
    process.env.WEB_PUSH_CONTACT,
    process.env.PUBLIC_VAPID_KEY,
    process.env.PRIVATE_VAPID_KEY
  );   
const payload = JSON.stringify({ 
  notification: { 
    // notification data
  }   
});  

webPush.sendNotification(pushSubscription, payload);

Bring client and server code together – users can now opt-in to timely updates from your PWA!

Step 7 – Optimize Performance

While PWAs can operate offline, providing performant experiences – especially on slower networks – remains important.

Some key ways to help improve performance:

🔂 Code splitting – Dynamically import JS bundles to decrease initial loads

Conditional loading – Only load non-critical resources as needed

💨 Compression – Shrink payload sizes of CSS/HTML/JS assets

💾 Caching – Store key assets like images, fonts, pages in the service worker

📸 Optimized images – Employ WebP, AVIF and responsive images

📱 PRPL pattern – Push critical resources for initial URL route first

Leveraging Lighthouse reports help track Core Web Vital metrics like:

Lighthouse progressive web app metrics

Optimizing web performance and leveraging service worker caching capacities allows building reliably fast and smooth progressive web apps – regardless of network quality.

Step 8 – Design Effective Push Notification Experiences

Push messages provide a channel for continually re-engaging users over weeks and months by sending timely, valuable updates – even when they aren‘t actively using your app.

Some UX best practices include:

⏱️ Timeliness – Send notifications as close to events as possible rather than batched. Immediacy signals value.

🫂 Personalization – Tailor messaging using names, interests or behaviors to better resonate. One generic message blasted to all users has lower relevance and engagement.

📊 Adaptability – Evolve targeting over time based on signals like user engagement with certain notification categories.

⚙️ User preferences – Provide settings for users to customize the types or frequency of notifications they desire. Put them in control.

👉 Actionability – Include call-to-action buttons directly within notifications to facilitate quick intended actions.

🚨 Avoid oversending – Focus on quality over quantity, as too many unwanted notifications lead users to mute or unsubscribe altogether.

The ultimate goal is crafting notifications users delight in rather than find disruptive – guiding them to valuable content or features at just the right times.

Conclusion

Transforming normal websites into progressive web apps helps provide more immersive, app-like experiences for your users leveraging common web technologies like JavaScript, CSS and HTML.

By following this guide you unlocked capabilities like:

📱 Installability on devices‘ home screens for quick access

💾 Intelligent offline support

🎉 Push notifications

⏱️ Background data syncing

📈 And opportunities for enhanced user engagement

On top of those baseline features, be sure to:

💻 Continually monitor and improve performance

🔔 Craft engaging notifications experiences

🚀 And innovate by leveraging emerging browser APIs

The result is a cost-effective web app that feels like a native application – with the added reach, links and discoverability of the web.

So try applying these techniques to save on development costs compared to native apps, reuse your web skills and bring convenience and versatility to more app-like experiences!

Let me know if you have any other questions on your journey to building an amazing progressive web app. I‘m happy to help or clarify any concepts as you embark on this.