Ruby on Rails is an integrated web application framework written in Ruby that is designed to make web development simple and enjoyable. It includes everything needed to build database-backed web applications according to the model-view-controller pattern, including an object-relational mapper (ORM), web server gateway interface (WSGI) compliant web server, and web page template system. Over 150,000 downloads and 400+ professionals from 55 countries use Rails for its convention over configuration design, instant feedback, and ability to change code on the fly without restarts.