APC, which means Alternative PHP Cache, is a framework used for caching the compiled source code of a script app, which could speed up a database-driven site several times. Every time a PHP page is accessed, the script pulls the website content that has to be loaded from a database, parses and compiles the program code, and the result is shown to the visitor. While this is necessary for Internet sites with frequently changing content, it is a complete waste of processing time and resources for an Internet site which does not change, for instance an informational portal which shows the very same content on a regular basis. When the webpages for such an Internet site are compiled, APC caches them and delivers them whenever a visitor opens them. Since this saves the time to request content from the database and to parse and compile the code, the Internet site will load much quicker. APC is very useful in particular for scripts with larger source code.