Zend Framework is an open source application framework. Zend Framework was initially released in 2006.
Zend Framework 2 is an open source framework for developing web applications and services using PHP 5.3+. Zend Framework 2 uses 100% object-oriented code and utilises most of the new features of PHP 5.3, namely namespaces, late static binding, lambda functions and closures.
Zend Framework 2 evolved from Zend Framework 1, a successful PHP framework with over 15 million downloads.
The component structure of Zend Framework 2 is unique; each component is designed with few dependencies on other components. ZF2 follows the SOLID object oriented design principle. This loosely coupled architecture allows developers to use whichever components they want. We call this a "use-at-will" design. We support Pyrus and Composer as installation and dependency tracking mechanisms for the framework as a whole and for each component, further enhancing this design.
We use PHPUnit to test our code and Travis CI as a Continuous Integration service.
While they can be used separately, Zend Framework 2 components in the standard library form a powerful and extensible web application framework when combined. Also, it offers a robust, high performance MVC implementation, a database abstraction that is simple to use, and a forms component that implements HTML5 form rendering, validation, and filtering so that developers can consolidate all of these operations using one easy-to-use, object oriented interface. Other components, such as Zend\Authentication and Zend\Permissions\Acl, provide user authentication and authorization against all common credential stores.
Still others, with the ZendService namespace, implement client libraries to simply access the most popular web services available. Whatever your application needs are, you're likely to find a Zend Framework 2 component that can be used to dramatically reduce development time with a thoroughly tested foundation.
The principal sponsor of the project 'Zend Framework 2' is Zend Technologies, but many companies have contributed components or significant features to the framework. Companies such as Google, Microsoft, and StrikeIron have partnered with Zend to provide interfaces to web services and other technologies they wish to make available to Zend Framework 2 developers.
Zend Framework 2 could not deliver and support all of these features without the help of the vibrant Zend Framework 2 community. Community members, including contributors, make themselves available on mailing lists, IRC channels and other forums. Whatever question you have about Zend Framework 2, the community is always available to address it.
-Zend Framework developer