About Yii

Yii is a high-performance PHP framework best for developing Web 2.0 applications.

Yii helps Web developers build complex applications and deliver them on-time.

Yii is pronounced as Yee or [ji:], and is an acronym for "Yes It Is!". This is often the accurate, and most concise response to inquires from those new to Yii:
Is it fast? ... Is it secure? ... Is it professional? ... Is it right for my next project? ... Yes, it is!

Yii is a free, 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.

To learn more about what Yii brings to the table, check out the features section.


Yii is the brainchild of its founder, Qiang Xue, who started the Yii project on January 1, 2008. Qiang previously developed and maintained the Prado framework. The years of experience gained and developer feedback gathered from that project solidified the need for an extremely fast, secure and professional framework that is tailor-made to meet the expectations of Web 2.0 application development. On December 3, 2008, after nearly one year's development, Yii 1.0 was formally released to the public.

Its extremely impressive performance metrics when compared to other PHP-based frameworks immediately drew very positive attention and its popularity and adoption continues to grow at an ever increasing rate.


Yii incorporates many ideas and work from other well-known Web programming frameworks and applications. Below is a short list of those from which Yii drew inspiration.

  • Prado: This is the major source of ideas for Yii. Yii adopts its component-based and event-driven programming paradigm, database abstraction layers, modular application architecture, internationalization and localization, and many of its other features and patterns.
  • Ruby on Rails: Yii inherits its spirit of convention over configuration. Yii also referenced its implementation of the active record design pattern for its ORM layer.
  • jQuery: This is integrated in Yii as the foundational JavaScript framework.
  • Symfony: Yii referenced its filter design and plug-in architecture.
  • Joomla: Yii referenced its modular design and message translation scheme.
Current Developer Team
Washington DC, USA
member since Jan 2008
founder and project lead
member since Mar 2010
core framework development
Rovinj, Croatia
member since Aug 2010
core framework development
Berlin, Germany
member since Aug 2012
core framework development
Donetsk, Ukraine
member since Mar 2013
core framework development
Majorca, Balearic Islands, Spain
member since May 2013
core framework development
Past Team Members
Mar 2013
Jan 2008 - Dec 2014
Sep 2009 - Dec 2014
Sep 2010 - Dec 2014
Aug 2010 - May 2012
Sep 2009 - Aug 2010
Sep 2009 - Mar 2010