A Progressive Web App (PWA) is a website built with extra browser features so it acts like an installed app. People can add it to their home screen, open it without typing a URL, use it offline, and receive push notifications, all from one codebase that still runs in a normal browser.
Imagine a regular shop that also hands you a loyalty card. Nothing about the shop changes, but now you have a quick way back in and a few perks. A PWA adds that same convenience layer on top of your site through a service worker, which is a small background script that caches files and handles offline behaviour. Because it is still the web, it relies on solid responsive design and fast loading to feel right on a phone. Many PWAs are built as a single-page application so navigation stays instant after the first load. Twitter Lite and the Starbucks order app are well-known examples, both built as PWAs to reach users on patchy connections.
The payoff is reach without an app store. You skip the review process, the separate download, and the cost of building twice for iOS and Android. One web build serves Android, iOS and desktop, which keeps the maintenance bill down and the feature set in sync. Performance still matters a lot, so techniques like lazy loading keep the first screen light while the rest loads in the background. The catch: iOS supports PWAs less fully than Android, so push notifications and install prompts behave differently on an iPhone, and that gap is worth checking before you commit.
At TopDevs we build PWAs when a client needs app-like reach without the cost of two native apps, focusing on offline behaviour and speed so it feels native from the first tap.
