APC, which is an acronym for Alternative PHP Cache, is a framework used for caching the compiled source code of a script application, which could speed up a database-driven Internet site several times. Each time a PHP page is opened, the script pulls the website content which needs to be shown from a database, parses and compiles the program code, and the result is displayed to the website visitor. While this is necessary for Internet sites with routinely changing content, it is a total waste of processing time and resources for a site that does not change, for example an informational portal which displays the very same content all the time. As soon as the webpages for such a site are compiled, APC caches them and delivers them any time a website visitor opens them. As this saves the time to request content from the database and to parse and compile the program code, the website will load a lot quicker. APC is very helpful in particular for scripts with larger source code.