Yii is an open source, object-oriented, component-based MVC PHP web application framework. Yii is pronounced as "Yee" or [ji:] and in Chinese it means "simple and evolutionary" and it can be an acronym for "Yes It Is!".
History Yii started as an attempt to fix perceived drawbacks of the PRADO framework: Slow handling of complex pages, steep learning curve and difficulty to customize many controls. In October 2006, after ten months of development, the first alpha version of Yii was released, followed by the formal 1.00 release in December 2008.
Yii 1.1 was released in January 2010 adding a form builder, relational Active record queries, a unit testing framework and more. The Yii community continues to follow the 1.1 branch with PHP7+ support and security fixes. The latest version 1.1.23 was released in December 2020.
In May 2011 the developers decided to use new PHP versions and fix architectural shortcomings, resulting in version 2.0. In May 2013 the Yii 2.0 code went public, followed by the first stable release in October 2014. PHP8 is supported since version 2.0.38. The latest version 2.0.51 was released in July 2024.
Yii 3.0 was released in December 2025. Yii3 works with the PHP ecosystem in depth. It integrates with any PHP library. Yii3 uses modern PHP standards enabling the leverage of the ecosystem's innovation. The central part of the framework is its dependency injection container. It brings all the individual packages together, automatically resolving dependencies and helping to obtain classes requested.
Version history Color Meaning Red Old version; no longer supported Yellow Old version; still supported Green Current version Blue Future version
VersionRelease dateEnd of active supportEnd of security/compatibility supportRequirement 1.0 December 3, 2008 December 31, 2010 PHP 5.1.0 or above 1.1 January 10, 2010 November 22, 2015December 31, 2026 PHP 5.1.0 or above 2.0 October 12, 2014 30 May, 202423 November, 2027 PHP 7.4.0 or above 3.0 December 31, 2025 31 December, 203031 December, 2035 PHP 8.2.0 or above
Extensions The Yii project includes a repository of user-contributed extensions in addition to an official extension library, zii, which was merged with the core framework; it has been bundled in every release since Yii version 1.1.0 and includes additional widgets such as grids and jQuery UI.
See also Active record pattern Comparison of web frameworks Model–view–controller Scaffold (programming)
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