fast common gateway interface (FCGI)

Fast Common Gateway Interface (FCGI) is a further development of the Common Gateway Interface(CGI). The protocol provides the interface between interactive programs with a web server. The goal of FastCGI is to reduce the overhead that accompanies the web server's interfacing with CGI programs. This allows the web server to handle more web page requests at the same time.

FastCGI is a programming interface that addresses certain weaknesses of the CGI protocol, such as limited efficiency and scalability under heavy load, and speeds up Web applications. User requests using a specific application program are processed about ten times faster with FastCGI than with the CGI protocol. As a plug-in for the web server, using FastCGI requires only minor changes to existing server applications.

FCGI was first introduced in the 1990s and was a response to Netscape's own NSAPI for Web application development. Some Web server vendors have implemented the open-market development FCGI in their products. Compared to other techniques that also focus on speeding up and simplifying server subroutines, FCGI follows CGI paradigms.