Yii is another free, open-source framework for PHP5. It promotes clean, DRY design, and rapid development. The Yii framework allows us to quickly and easily write optimized web applications. It also offers excellent documentation and a supportive community and it is time-tested yet stable. Yii helps you create web applications quickly that perform pretty well. Features: Model-View-Controller architecture - MVC Support helps in improving the performance, allows better documentation, and has a range of built-in functionalities. Database Access Objects (DAO), Active Record, and programmatic Database migrations allow you to build migrating database-powered web applications. Form input, validation, and Ajax support are all built-in Yii. Built-in authentication and user management extensions make it easy to launch a new App. Yii has a built-in code generation tool, Gii that speeds the development of your application. Theme options make elegant responsive applications much simpler. It helps to minimize the risk factors of running services with PHP and MySQL. It also offers a variety of free, open-source plugins and widgets.