Ruby on Rails (Rails) is a full-stack web application framework written in the Ruby programming language. A framework is a body of ready-made code and conventions on which an application is built. Rails follows the Model-View-Controller (MVC) pattern, which splits an app into models (data and business rules), views (the pages) and controllers (code that handles each request). More than six thousand people have contributed code to it.
Active Record maps database tables to Ruby objects, with associations between tables, callbacks on save and encrypted fields. Action Controller processes incoming requests and responds with HTML or JSON; Action View mixes Ruby into HTML templates; Action Dispatch connects URLs to controllers. The framework also sends and receives email, keeps pages live through WebSockets, queues background jobs, stores uploads in the cloud and protects against common attacks. Hotwire is its default front-end framework. Rails favours convention over configuration: standard names and folder layouts replace most setup files.
Rails is free and open source under the MIT license, with its source code on GitHub.