Common Gateway Interface

In <a href="/facts/Computing/Kghtm9fX">computing</a>, Common Gateway Interface (CGI) is an interface specification that enables <a href="/facts/Web_server/A4GS6thA">web servers</a> to execute an external program to process <a href="/facts/HTTP/TWtvf7JD">HTTP</a> or <a href="/facts/HTTPS/MSWYz4zo">HTTPS</a> user requests.
Such programs are often written in a <a href="/facts/Scripting_language/8pF4ajBL">scripting language</a> and are commonly referred to as CGI scripts, but they may include <a href="/facts/Compiler/WNfCDFJe">compiled</a> programs.
A typical use case occurs when a web user submits a <a href="/facts/Web_form/9Ivp2peo">web form</a> on a web page that uses CGI. The form's data is sent to the web server within a <a href="/facts/HTTP_request/TWtvf7JD">HTTP request</a> with a <a href="/facts/URL/pPD5g7Wq">URL</a> denoting a CGI script. The web server then launches the CGI script in a new <a href="/facts/Computer_process/Vcq7EnUV">computer process</a>, passing the form data to it. The CGI script passes its output, usually in the form of <a href="/facts/HTML/sSc3fT78">HTML</a>, to the Web server, and the server relays it back to the browser as its <a href="/facts/HTTP_response/TWtvf7JD">response</a> to the browser's request.
Developed in the early 1990s, CGI was the earliest common method available that allowed a web page to be interactive. Due to a necessity to run CGI scripts in a separate process every time the request comes in from a client, various alternatives were developed.

Common Gateway Interface open-in-new

Common Gateway Interface