Zend Optimizer is a well-known software, which is required to run files encoded with Zend Guard. The aforementioned encodes files created in PHP 4, PHP 5, PHP 7 and PHP 8 in order to protect them from reverse engineering and unauthorized use, thus guarding copyright protected source code. In case you need to protect your custom-made script, for instance, you're able to employ Zend Guard and your program code will no longer be human readable, but you will also need Zend Optimizer on the server where you host your site. A lot of pre-made script-driven applications, particularly ones that are paid, also require Zend Optimizer in order to work correctly because their core code is often not free to modify. Websites which use the tool are usually quicker because their program code is already optimized and pre-compiled.