PWA (Progressive Web App)

A Progressive Web App (PWA) is a website built with modern web features so that it behaves like an installed app. Users can add it to the home screen, and it opens in its own window, works offline or on slow networks, and can send push notifications.

A PWA needs HTTPS, a web app manifest (a JSON file with the name, icons and colours) and a service worker, a script that caches files and handles requests when there is no connection. PWAs come from a single codebase and do not need an app store, though they can also be listed in one.