A Progressive Web App, commonly known as PWA, is a type of web application built using common web technologies such as HTML and JavaScript. W3C defines them as: "applications that have a broad reach across all modern devices"

Progressive web applications are a new category of apps that use familiar web technologies like HTML and JavaScript to provide a rich user experience. They have the same features as regular web apps, but are built with stand-alone code that runs offline in the browser, enabling them to work without an internet connection.

Progressive web apps are a collection of features that, starting today, will make it easier to build, run and scale your app faster. We’re going to allow developers to embed a web-based version of their app on any device with a browser and access it right in the app store. This will give users access to all the same functionality of their full desktop experience without having to download an entire app onto their phone or tablet. That means you can start using your app as soon as you’ve uploaded it with no additional hoops to jump through. ​