Yii is a high-performance PHP framework best for developing Web 2.0 applications. Yii comes with a rich feature set including MVC, DAO/ActiveRecord, I18N/L10N, caching, authentication and role-based access control, scaffolding and testing units. It can reduce your development time significantly.
Yii is pronounced as Yee or [ji:], and is an acroynym for “Yes It Is!“.
Yii is an open-source Web application development framework written in PHP5 that promotes clean, DRY design and encourages rapid development. It works to streamline your application development and helps to ensure an extremely efficient, extensible, and maintainable end product.
Being extremely performance optimized, Yii is a perfect choice for any sized project. However, it has been built with sophisticated, enterprise applications in mind. You have full control over the configuration from head-to-toe (presentation-to-persistence) to conform to your enterprise development guidelines. It comes packaged with tools to help test and debug your application, and has clear and comprehensive documentation.