Below is a table that lists all extensions typically found in PHP, and how they are used in Zend Framework. This can help guide you to know which extensions are required for your application. Not all extensions used by Zend Framework are required for every application.

A usage type of "Dependency" means that the components or classes are not usable if the respective extension is not available. A usage type of "Optional" means that if the extension is not available, the components or classes automatically fall back to use alternative code.