Progressive Web App (PWA): What It Is and How It Works

Ever used a website on your phone that felt surprisingly slick, loaded instantly even on a shaky connection, and even asked if you wanted to add it to your home screen? You’ve likely encountered a progressive web app (PWA).

A progressive web app is a type of web application that uses modern web technologies to deliver an experience so fast, reliable, and engaging that it feels just like a native app you’d download from an app store. It’s the best of both worlds: the broad accessibility of the web combined with the rich features of a dedicated application.

The Core Idea: Bridging the Gap Between Web and Native Apps

For years, developers and businesses faced a tough choice. Do you build for the web platform, reaching anyone with a browser and a link? Or do you build a platform specific app (one for iOS, another for Android) to get better performance and deeper device integration?

This created a classic trade off between capability and reach.

• Websites offered incredible reach. A single site works everywhere, is easily shareable, and can be found on search engines. But historically, they lacked capability. They couldn’t work offline, send push notifications, or access many device features.
• Native Apps offered amazing capability. They could access your camera, GPS, and contacts, work offline, and sit on your home screen. But their reach was limited. You had to convince a user to find you in a crowded app store, download a large file, and give you precious screen space.

A progressive web app aims to eliminate this trade off. It starts as a regular website but progressively enhances itself, gaining app like features in modern browsers. The goal is to bridge web and native, delivering native app capabilities with the massive reach and ease of access of the web.

The State of PWA Adoption

The global PWA market is projected to grow substantially, expected to exceed $15 billion by 2025. This growth isn’t just a forecast; it’s a market correction driven by a focus on cost, speed, and user experience. Many leading companies have built successful PWAs, including Twitter, Starbucks, Pinterest, and Forbes. These companies report significant increases in engagement, conversions, and user satisfaction.

Factors driving this adoption include:

• Maturing Technology: Browser support for PWA features is now nearly universal, making development more straightforward.
• User Expectations: With over 60% of web traffic coming from mobile, users demand fast, app like experiences on the web.
• Business Needs: Companies need to deliver on multiple platforms without massive development budgets, and PWAs offer a cost effective solution.

The Key Benefits of Building a Progressive Web App

The real reason PWAs are gaining momentum is because they deliver tangible results for businesses and a better experience for users.

1. Blazing Fast Performance and Higher Engagement

PWAs are designed for speed. By intelligently caching resources, they can load in a fraction of the time of a traditional website, which is critical when users expect pages to load in under three seconds.

• Fact: After launching their PWA, AliExpress saw conversion rates for new users increase by 104%.
• Fact: The travel site MakeMyTrip achieved a 3x increase in conversion rates with its PWA.
• Fact: The cosmetics brand Lancôme saw a 17% higher conversion rate on its PWA.
• Fact: Flipkart’s PWA led to a 70% increase in conversions and a tripling of time spent on the site.

2. Unbeatable Reliability with Offline Functionality

One of the most powerful features of a PWA is its ability to work without an internet connection. Using a technology called a Service Worker, a PWA can cache its core user interface and previously viewed content.

• Fact: Starbucks launched a PWA that allowed users to browse the menu and customize orders offline, which resulted in a doubling of their daily active users.

3. No App Store Friction

PWAs can be “installed” directly from the browser to a user’s home screen, bypassing app stores entirely. This low friction process means more users are likely to add your app to their device.

• Fact: Pinterest saw a 40% increase in time spent on their site after launching their PWA, which offered a faster, app like experience without a formal download.

4. Massive Cost Savings and Cross Platform Reach

Instead of building and maintaining separate apps for iOS, Android, and the web, you build one progressive web app that works everywhere.

• Fact: Developing a PWA can be 3 to 4 times cheaper than building separate native apps.
• Fact: Businesses can see a significant reduction in ongoing maintenance costs compared to managing dual platform native apps.

This “build once, run everywhere” model is a huge advantage, especially for startups and agile teams. Platforms like WeWeb’s visual web app builder take this even further, allowing you to build a powerful, production grade progressive web app visually, dramatically accelerating your time to market.

How Does a Progressive Web App Actually Work? The Tech Explained

The magic behind a PWA isn’t really magic at all. It’s a combination of three key web technologies.

Web App Manifest

The web app manifest is a simple JSON file that tells the browser about your PWA. It defines things like the app’s name, the icons to use on the home screen, the app’s primary colors, and how it should launch (for example, in a full screen window without a browser address bar). This file is what makes a website installable.

Service Worker API

The service worker API is the real workhorse of a progressive web app. A service worker is a script that your browser runs in the background, separate from the web page. This allows it to intercept network requests, manage a cache of responses, and enable features that don’t need a visible web page, like push notifications.

This background script is what enables:

• Offline Operation: When you’re offline, the service worker can intercept requests and serve files from a local cache instead of the network, allowing the app to load and function.
• Background Sync: It can perform tasks like syncing data even when the app’s tab is closed.
• Advanced Caching: Developers can implement sophisticated rules to balance speed and freshness, such as showing cached content immediately while fetching an update in the background.

IndexedDB

For storing more complex data offline, PWAs use IndexedDB. Think of it as a complete NoSQL database built right into the browser. It’s perfect for storing user data, articles, or product catalogs so the app can be fully functional without a connection.

Beyond Mobile: PWAs on Other Devices

While often discussed in a mobile context, a key strength of the progressive web app is its universal nature. The same PWA that a user installs on their phone can be installed and run on desktops (macOS, Windows, ChromeOS) and tablets.

On desktop, PWAs deliver an integrated, app like experience. They can be pinned to the taskbar or dock, launch in their own standalone window, and operate without the browser’s user interface. Advanced APIs like the Window Controls Overlay API even allow a desktop PWA to take over the entire application window, creating a completely custom and immersive interface. This true cross platform capability means a single codebase can serve your entire audience, regardless of what device they use.

Essential PWA Features and APIs for an App Like Experience

Beyond the core components, a rich ecosystem of web APIs allows a progressive web app to achieve true parity with native apps.

• Notifications API: This works with the Push API to let you send push notifications to users, reengaging them with timely updates. Support for this landed on iOS in 2023, making it a truly cross platform feature.
• Badging API: Allows a PWA to display a small badge on its home screen icon, just like a native app showing the number of unread messages.
• Web Share API: Lets your app hook into the device’s native sharing capabilities, so users can share content directly to their contacts or other installed apps.
• Other Web APIs: The web platform is constantly evolving. A huge collection of other web API options exist for accessing device hardware like Bluetooth, geolocation, and even the file system, further closing the capability gap with native apps.

Getting Your PWA Discovered: App Store Distribution

While a primary advantage of PWAs is bypassing app stores, distribution through them is still possible and can increase visibility.

• Google Play Store: PWAs can be packaged and listed on the Google Play Store. This typically involves using a tool to wrap the PWA into a format that the store accepts, allowing it to be discovered and downloaded just like a native Android app.
• Microsoft Store: The Microsoft Store on Windows has embraced PWAs. High quality PWAs can be listed alongside native applications, giving them a trusted distribution channel. Microsoft’s own tools and crawlers can even help identify and package PWAs for the store.
• Apple App Store: Listing a PWA on the Apple App Store is more challenging. Apple’s guidelines are stricter, and you generally cannot submit a PWA directly. Developers often need to wrap the PWA in a native shell and add significant native functionality to meet Apple’s requirements for what constitutes an “app”.

This hybrid approach gives developers the reach of the web plus the discoverability of a traditional app store.

Common Challenges and Best Practices for PWAs

While powerful, building a great progressive web app comes with some considerations.

PWA Challenges

The primary challenge has been inconsistent browser support, though this gap is closing rapidly.

• Cross Browser Compatibility: While major features are widely supported, some advanced APIs or the way installation prompts are handled can differ between browsers, particularly on iOS.
• Device Integration Limits: PWAs still can’t access everything a native app can, such as telephony or certain low level hardware features like NFC on iOS.
• User Awareness: A significant hurdle is that many users simply don’t know a website can be “installed”. The “Add to Home Screen” option can be less obvious than a large install button in an app store.

PWA Best Practices

To overcome these challenges and deliver a fantastic experience, follow these PWA best practice guidelines.

• Be Responsive: Ensure your app looks and works great on any screen size, from a small phone to a large desktop monitor.
• Design for Offline First: Always provide a custom offline experience, even if it’s just a simple message. Never let the user see the browser’s default “no internet” page.
• Use HTTPS: Security is mandatory. Service workers and many modern APIs only work on secure connections. Pair HTTPS with Auth0 authentication for secure login and role management.
• Optimize for Performance: Keep your app fast and lightweight. An app shell model, where the UI skeleton is cached, makes return visits feel instant.
• Make it Discoverable: Because a PWA is a website, it’s indexable by search engines. Use standard SEO practices to ensure users can find you, and track key events with Google Tag Manager integration.

How to Get Started with Your Own PWA

If you’re ready to build a progressive web app, there are countless resources available. You can also jumpstart your build with customizable app templates. You can find a guide or tutorial that provides step by step instructions, a how to article for a specific task, or deep technical reference documents on sites like MDN or web.dev.

However, building a PWA from scratch requires technical knowledge. This is where a visual development platform can change the game. Instead of hand coding every component, you can use a tool like WeWeb to build your custom application visually. It also offers integrations with Airtable, Google Sheets, GraphQL, and more so your PWA connects to the tools you already use.

For teams that value speed, WeWeb AI can scaffold pages, data bindings, and components from plain English prompts. You get all the benefits of a progressive web app (performance, offline capabilities, and installability) without the steep learning curve. It’s the fastest way to turn your idea into a production ready app that works for everyone, everywhere. Book a live demo to see it in action.

Frequently Asked Questions about Progressive Web Apps

What is the main difference between a progressive web app and a native app?

A native app is written in a platform specific language and must be downloaded from an app store. A PWA is built with web technologies (HTML, CSS, JavaScript) and runs in the browser, but can be “installed” on a device’s home screen for an app like experience.

Do PWAs work on iOS and iPhones?

Yes. Modern versions of iOS and Safari fully support the core technologies behind PWAs, including service workers for offline functionality and web push notifications (as of iOS 16.4). The installation process is slightly different, requiring the user to tap “Share” and then “Add to Home Screen”.

Can any website become a progressive web app?

Yes, technically any website can be enhanced to become a PWA. The core requirements are a secure HTTPS connection, a Web App Manifest file, and a registered service worker.

What are some famous progressive web app examples?

Many leading companies have built successful PWAs, including Twitter, Starbucks, Pinterest, Uber, The Washington Post, and Forbes. These companies have reported significant increases in engagement, conversions, and user satisfaction. Explore real world examples built with WeWeb.