Zend Framework is a collection of professional PHP packages with more than 570 million installations. It can be used to develop web applications and services using PHP 5.6+, and provides 100% object-oriented code using a broad spectrum of language features.
Zend Framework uses Composer as a package dependency manager; PHPUnit to test all packages; and Travis CI as a Continuous Integration service. Zend Framework also follows PHP-FIG standards, and includes an implementation of PSR-7 for HTTP message interfaces (as shepherded by Matthew Weier O'Phinney, Zend Framework project lead).
Zend Framework 3 evolved from both Zend Framework 2 and 1; cumulatively, the previous versions were downloaded more than 15 million times.
The principal sponsor of Zend Framework is Zend, a Rogue Wave Company, but many others 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 ZF developers.
Zend Framework 3 could not deliver and support all of these features without the help of the vibrant community. Community members, including contributors, make themselves available on mailing lists, IRC channels and other forums. Whatever question you have about Zend Framework, the community is always available to address it.