Cold Fusion is an example of a Common Gateway Interface application. The Common Gateway Interface is a mechanism to allow Web servers, which are designed to serve static documents, to receive dynamic output from programs and serve it as if it were static data.

1. When a browser sends a request for a Cold Fusion template to a Web server, several things must happen. First, the Web server recognizes the information from the browser as a request for CGI output.
2.If the request was initiated from a form, the server has to write the form field information to some area in storage that is accessible to other programs on the machine. Usually, this is done by using STDOUT data streams. The WinCGI interface, which can be used by WebSite and other servers, writes the form data to INI-style files on disk, which are then opened and read by the CGI application.
3.The CGI program requests data from the data source, which is returned in step
4. The CGI program formats the data as HTML output, returning this output to the server in step
5. The server receives this output, performs any further server-side processing necessary, and then sends it to the browser.

Cold Fusion defaults to using server API modules instead of CGI to communicate between the Web Server and ColdFusion Application Server.