FastCGI

FastCGI stands for Fast Common Gateway Interface. It is a protocol, built on top of CGI. Unlike CGI, FastCGI has persistent processes that can handle more than one request before being destroyed. It also implements multiplexing.

PHP may be build as a fast CGI, in the php-fpm demon.

Documentation

Related : FastCGI Process Manager (FPM), Common Gateway Interface (CGI), Command Line Interface (CLI)