APC, which is an acronym for Alternative PHP Cache, is a framework used for caching the compiled source code of a given script app, which can speed up a database-driven site several times. Every time a PHP web page is opened, the script pulls the website content which needs to be shown from a database, parses and compiles the code, and the result is displayed to the site visitor. While this is necessary for websites with constantly changing content, it is a complete waste of processing time and system resources for a website that does not change, for instance an informational portal that shows identical content on a regular basis. Once the webpages for such a website are compiled, APC caches them and delivers them each time a visitor loads them. Since this saves the time to request content from the database and to parse and compile the program code, the Internet site will load considerably faster. APC is very useful in particular for scripts with massive source code.