APC, which is an acronym for Alternative PHP Cache, is a framework used for caching the compiled source code of a script app, that can speed up a database-driven Internet site several times. Each time a PHP web page is opened, the script pulls the site content that needs to be displayed from a database, parses and compiles the code, and the result is shown to the website visitor. While this is necessary for Internet sites with regularly changing content, it is a complete waste of processing time and system resources for a site that doesn't change, for example an informational portal that displays the exact same content all the time. Once the webpages for such a website are compiled, APC caches them and delivers them whenever a visitor opens them. As this saves the time to collect content from the database and to parse and compile the program code, the site will load considerably faster. APC is very effective in particular for scripts with large source code.