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Progressive Web App (PWA)

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Filed underFront EndSoftware EngineeringMobile Development
In brief · quick answer

A Progressive Web App (PWA) is a web application that uses modern browser capabilities to provide an app-like experience: it can be installed on the device, work offline, send push notifications, and access device features, all while being delivered through the web.

§ 1 Definition

A Progressive Web App (PWA) is a web application built with standard web technologies that behaves like a platform-specific (native) app. PWAs combine the reach of the web (instant updates, no app store, linkable) with the capabilities of native apps (offline support, push notifications, home screen installation, full-screen mode). The three core requirements for a PWA are: Capability (using modern web APIs like Service Workers, Cache API, and IndexedDB for offline and background functionality), Reliability (the app loads and works even with poor or no network connectivity), and Installability (the app can be added to the device home screen through a browser prompt, appearing in the app launcher like any installed app). PWAs use a Web App Manifest (a JSON file that defines the app name, icons, theme colors, and display mode) and a Service Worker (a JavaScript file that intercepts network requests and manages caching strategies).

§ 2 Core Technologies

PWAs require three technologies. A Web App Manifest (manifest.json) defines how the app appears when installed: name, icons, start URL, display mode (fullscreen, standalone, minimal-ui), theme color, and background color. A Service Worker is a JavaScript file that runs in the background, separate from the page, intercepting network requests and serving cached responses. It enables offline functionality, background sync, and push notifications. HTTPS is mandatory because Service Workers require a secure context and prevent man-in-the-middle attacks.

§ 3 Caching Strategies

Service Workers support multiple caching strategies. Cache First serves from cache, falling back to network. Network First tries the network first, falling back to cache. Stale While Revalidate serves the cached version instantly while fetching a fresh version in the background. Network Only bypasses the cache entirely. The right strategy depends on the resource type: static assets use Cache First, API responses use Network First or Stale While Revalidate, and sensitive data uses Network Only.

§ 4 Note

Common misunderstanding: A PWA is not a type of app you build with a framework. It is a set of capabilities you add to an existing web application. Any website can become a PWA by adding a manifest and a service worker. Another misconception: PWAs cannot compete with native apps. For many use cases (retail, news, travel, productivity tools), PWAs provide comparable experiences at a fraction of the development cost. PWAs also avoid the 15-30% app store commission.

§ 5 Common questions

Q. Do PWAs work on iOS?
A. Yes, but with limitations. Safari supports Service Workers and the Web App Manifest, but some APIs (push notifications, background sync) are not available on iOS. iOS 16+ improved PWA support with web push notifications.
Q. Can PWAs access device hardware (camera, GPS, Bluetooth)?
A. Yes. PWAs can access the camera (getUserMedia), GPS (Geolocation API), Bluetooth (Web Bluetooth), USB (WebUSB), and file system (File System Access API). Support varies by browser.
Key takeaways
  • PWAs are regular web applications enhanced with Service Workers and a Web App Manifest for offline and installable capabilities.
  • Three requirements: HTTPS, Service Worker, Web App Manifest.
  • PWAs are not a replacement for native apps but offer a cost-effective alternative for many use cases.
How Atomic Glue helps

Atomic Glue builds PWAs for clients who want the reach of the web with the capabilities of a native app. We implement Service Worker caching strategies tailored to your content, optimize for Lighthouse PWA audits, and ensure cross-browser compatibility. A well-built PWA can reduce bounce rates on slow networks, improve engagement through push notifications, and save clients the cost of a native app development project. We evaluate PWA viability during every website development engagement.

Get in touch
Written by Atomic Glue Development Team, Atomic Glue · Last updated June 2026
# Progressive Web App (PWA)

A Progressive Web App (PWA) is a web application that uses modern browser capabilities to provide an app-like experience: it can be installed on the device, work offline, send push notifications, and access device features, all while being delivered through the web.

Category: Front End (also: Software Engineering, Mobile Development)

Author: Atomic Glue Development Team

## Definition

A Progressive Web App (PWA) is a web application built with standard web technologies that behaves like a platform-specific (native) app. PWAs combine the reach of the web (instant updates, no app store, linkable) with the capabilities of native apps (offline support, push notifications, home screen installation, full-screen mode). The three core requirements for a PWA are: Capability (using modern web APIs like Service Workers, Cache API, and IndexedDB for offline and background functionality), Reliability (the app loads and works even with poor or no network connectivity), and Installability (the app can be added to the device home screen through a browser prompt, appearing in the app launcher like any installed app). PWAs use a Web App Manifest (a JSON file that defines the app name, icons, theme colors, and display mode) and a Service Worker (a JavaScript file that intercepts network requests and manages caching strategies).

## Core Technologies

PWAs require three technologies. A Web App Manifest (manifest.json) defines how the app appears when installed: name, icons, start URL, display mode (fullscreen, standalone, minimal-ui), theme color, and background color. A Service Worker is a JavaScript file that runs in the background, separate from the page, intercepting network requests and serving cached responses. It enables offline functionality, background sync, and push notifications. HTTPS is mandatory because Service Workers require a secure context and prevent man-in-the-middle attacks.

## Caching Strategies

Service Workers support multiple caching strategies. Cache First serves from cache, falling back to network. Network First tries the network first, falling back to cache. Stale While Revalidate serves the cached version instantly while fetching a fresh version in the background. Network Only bypasses the cache entirely. The right strategy depends on the resource type: static assets use Cache First, API responses use Network First or Stale While Revalidate, and sensitive data uses Network Only.

## Note

Common misunderstanding: A PWA is not a type of app you build with a framework. It is a set of capabilities you add to an existing web application. Any website can become a PWA by adding a manifest and a service worker. Another misconception: PWAs cannot compete with native apps. For many use cases (retail, news, travel, productivity tools), PWAs provide comparable experiences at a fraction of the development cost. PWAs also avoid the 15-30% app store commission.

## Common questions

Q: Do PWAs work on iOS?

A: Yes, but with limitations. Safari supports Service Workers and the Web App Manifest, but some APIs (push notifications, background sync) are not available on iOS. iOS 16+ improved PWA support with web push notifications.

Q: Can PWAs access device hardware (camera, GPS, Bluetooth)?

A: Yes. PWAs can access the camera (getUserMedia), GPS (Geolocation API), Bluetooth (Web Bluetooth), USB (WebUSB), and file system (File System Access API). Support varies by browser.

## Key takeaways

## Related entries

Last updated June 2026. Permalink: atomicglue.co/glossary/progressive-web-app-pwa-front-end

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