You will find a table listing all extensions typically found in PHP and how they are used in Zend Framework below. You should verify that the extensions on which Zend Framework components you'll be using in your application are available in your PHP environments. Many applications will not require every extension listed below.
A dependency of type "hard" indicates that the components or classes cannot function properly if the respective extension is not available, while a dependency of type "soft" indicates that the component may use the extension if it is available but will function properly if it is not. Many components will automatically use certain extensions if they are available to optimize performance but will execute code with similar functionality in the component itself if the extensions are unavailable.
Table 172. PHP Extensions Used in Zend Framework by Component