Once the plug-in is loaded, the administrator can configure when the server should invoke the SAF and what parameters it should be passed.
NSAPI can be compared to an earlier protocol named Common Gateway Interface (CGI).
Unlike CGI programs, NSAPI plug-ins run inside the server process.
In contrast to CGI programs, NSAPI SAFs can be configured to run at different stages of request processing.
For example: NSAPI, ISAPI and Apache API allow applications to run inside the server process.