It is used by the Ruby on Rails and Padrino frameworks to test applications in a development environment as well as production mode for small loads.

WEBrick has originated from an idea in an article named "Internet Programming with Ruby" in Open Design, a Japanese Engineering magazine.

It uses multiple independent servlets, joined together by the programmer, for handling CGI scripts, ERB pages, Ruby Blocks and directory listings to provide a web application or to service a request URI on a per-host or per-path basis.

During the development stage, there is no necessity for the installation of a discrete web server since WEBrick is already built into the Rails framework.

Various other ports as ‘virtual hosts’ can also be created at the same time which do not listen as shown below:[1] :DocumentRoot should be provided or an instance of a servlet should be set up to service a request URI; otherwise a 404 error will be returned.