In computing, a we application or we app is a chem-server computer program which the chem (including une user interface and client-side logic) runs in a 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 are those which have similar functionality to a desktop software, 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 the application:
- Responsive web design
- Progressive Web Apps
- Native apps or "mobile apps"
- Hybrid apps