In computing, a web application or web app is a client–server computer program which the client (including the user interface and client-side logic) runs in a web browser.

Common web applications include web mail, online retail sales, online auctions, wikis, instant messaging services and many other functions.The general distinction between a dynamic web page of any kind and a “web application” is unclear. Web sites most likely to be referred to as “web applications” are those which have similar functionality to a desktop software application, or to a mobile app. HTML 5 introduced explicit language support for making applications that are loaded as web pages, but can store data locally and continue to function while offline.

There are several ways of targeting mobile devices when making a web application:
– Responsive web design
– Progressive Web Apps
– Native apps or “mobile apps”
– Hybrid apps