Yii is a free high-performance component-based PHP framework best for developing large-scale Web applications. Yii is PHP 5 only. PHP 4 is not supported. Because of this, Yii is able to take use of many PHP 5 features.
Yii comes with a full stack of features:
- MVC design pattern
- DAO / ActiveRecord
- Internationalization and localization
- Caching
- jQuery-based AJAX support
- Authentication and role-based access control
- Input validation
- Widgets
- Events
- Theming
- Web services