|Initial release||March 3, 2006|
|Stable release||2.1.5 / April 17, 2013|
|Preview release||2.2.0rc1 / May 1, 2013|
|Written in||PHP 5|
|License||New BSD license|
Zend Framework is licensed under the Open Source Initiative (OSI)-approved New BSD License, and all code contributors must sign a Contributor License Agreement (CLA) based on the Apache Software Foundation’s CLA. The licensing and contribution policies were established to prevent intellectual property issues for commercial ZF users, according to Zend's Andi Gutmans.
Sponsor and partners 
Zend Technologies, co-founded by PHP core contributors Andi Gutmans and Zeev Suraski, is the corporate sponsor of Zend Framework. Technology partners include IBM, Google, Microsoft, Adobe Systems, and StrikeIron.
Zend Framework version 1.7 requires PHP 5.2.4 or later. Previous versions required PHP 5.1.4 or later, although the ZF Programmer's Reference Guide strongly recommended PHP 5.2.3 or later for security and performance improvements included in these versions of PHP. Zend Framework 2.0 requires PHP 5.3.3 or later. PHPUnit 3.0 or later is required to run the unit tests shipped with Zend Framework. Many components also require PHP extensions.
Zend Framework features include:
- All components are fully object-oriented PHP 5 and are E_STRICT compliant
- Use-at-will architecture with loosely coupled components and minimal interdependencies
- Extensible MVC implementation supporting layouts and PHP-based templates by default
- Support for multiple database systems and vendors, including MariaDB, MySQL, Oracle, IBM DB2, Microsoft SQL Server, PostgreSQL, SQLite, and Informix Dynamic Server
- Email composition and delivery, retrieval via mbox, Maildir, POP3 and IMAP4
- Flexible caching sub-system with support for many types of backends, such as memory or a file system.
Building and running Zend Framework applications 
Zend Framework applications can run on any PHP stack that fulfills the technical requirements.
Zend Technologies provides a PHP stack, Zend Server (or Zend Server Community Edition), which is advertised to be optimized for running Zend Framework applications. Zend Server includes Zend Framework in its installers, along with PHP and all required extensions. According to Zend Technologies, Zend Server provides improved performance for PHP and especially Zend Framework applications through opcode acceleration and several caching capabilities, and includes application monitoring and diagnostics facilities.
Zend Studio is an IDE that includes features specifically to integrate with Zend Framework. It provides an MVC view, MVC code generation based on Zend_Tool (a component of the Zend Framework), a code formatter, code completion, parameter assist, and more.
Zend Studio is not free software, whereas the Zend Framework and Zend Server Community Edition are free.
Zend Server is compatible with common debugging tools such as Xdebug.
Other developers may want to use a different PHP stack and another IDE such as Eclipse PDT which works well together with Zend Server. A preconfigured, free version of Eclipse PDT with Zend Debug is available on the Zend web site.
Code, documentation, and test standards 
Code contributions to Zend Framework are subject to rigorous code, documentation, and test standards. All code must meet ZF’s coding standards and unit tests must reach 80% code coverage before the corresponding code may be moved to the release branch.
Simple Cloud API 
On September 22, 2009, Zend Technologies announced that it would be working with technology partners including Microsoft, IBM, Rackspace, Nirvanix, and GoGrid along with the Zend Framework community to develop a common API to cloud application services called the Simple Cloud API. This project is part of Zend Framework and will be hosted on the Zend Framework website, but a separate site called simplecloud.org has been launched to discuss and download the most current versions of the API.
The Simple Cloud API and several Cloud Services are included in Zend Framework. The adapters to popular cloud services have reached production quality.
Current Development 
The first development release of Zend Framework 2.0 was released on August 6, 2010. Changes made in this release were the removal of require_once statements, migration to PHP 5.3 namespaces, a refactored test suite, a rewritten Zend\Session, and the addition of the new Zend\Stdlib. The second development release was on November 3, 2010
The first stable release of Zend Framework 2.0 was released 5 September, 2012.
Additional changes to be completed before final release include the reduced reliance of __call() magic methods, reduction of singleton classes (e.g. Zend\Controller\Front), and request based conditional module configuration in Zend\Application. The requirements of the MVC infrastructure of the next version of the framework are currently being discussed on its wiki.
Although the contributors of Zend Framework are actively encouraging the use of Zend Framework version 2.x, they will maintain version 1.x for the time being.
See also 
- "Archives". Zend Framework. Retrieved May 1, 2013.
- Weier O'Phinney, Matthew (April 17, 2013). "Zend Framework 2.1.5 Released!". ZF Blog. Retrieved May 1, 2013.
- Weier O'Phinney, Matthew (May 1, 2013). "Zend Framework 2.2.0rc1 Released!". ZF Blog. Retrieved May 1, 2013.
- "Introduction to Zend Framework". ZF Programmer's Reference Guide. Retrieved 2009-02-12.
- Gutmans, Andi (2005-10-27). "Zend Framework (post is too long so make sure to grab coffee)". Andi on Web & IT. Retrieved 2009-02-11.
- "History of PHP and related projects". The PHP Group. Retrieved 2009-02-11.
- LaMonica, Martin (2005-02-25). "IBM backs open-source Web software". cnet.com. Retrieved 2009-02-11.
- Kernel, Sean Michael (2006-12-20). "Google Data Joins PHP Zend Framework". internetnews.com. Retrieved 2009-02-11.
- Krill, Paul (2006-10-31). "Microsoft, Zend boost PHP for Windows". infoworld.com. Retrieved 2009-02-11.
- Potter, Mike (2008-07-31). "Adobe Contributing AMF Support to Zend Framework". The Official Flex Team Blog. Retrieved 2009-02-11.[dead link]
- "StrikeIron Featured Partners". Retrieved 2009-02-11.
- "Zend Framework Requirements". ZF Programmer's Reference Guide. Retrieved 2009-02-12.
- "About Zend Framework". Retrieved 2009-02-11.
- Zend site
- "Zend Framework Contributor Guide". 07-01-2006. Retrieved 2008-07-14.
- "Simple Cloud API Press Release". Retrieved 2009-11-05.
- "Zend Framework website". Retrieved 2009-11-05.
- "Zend Framework 2.0.0dev1". 2010-08-06. Retrieved 2010-09-04.
- "Zend Framework 2.0.0dev2". 2011-11-03. Retrieved 2011-03-18.
- "Zend Framework 2.0 Milestones". 2010-09-02. Retrieved 2010-09-04.
- Official Website
- Zend Framework by Examples (ZfEx)
- Zend Framework IRC Channels
- Zend Framework news, links and tutorials
- Russian Zend Framework Conference
- Zend framework VS Cake, Yii and Codeigniter comparison sheet