Netscape Server Application Programming Interface

The Netscape Server Application Programming Interface (NSAPI) is an application programming interface for extending server software, typically web server software.

NSAPI was initially developed by Rob McCool at Netscape for use in Netscape Enterprise Server. A variant of NSAPI can also be used with Netscape Directory Server.

Because there is no formal standard, applications that use NSAPI are not necessarily portable across server software. As of 2007, varying degrees of support for NSAPI are found in Sun Java System Web Server and Zeus Web Server.

Applications that use NSAPI are referred to as NSAPI plug-ins. Each plug-in implements one or more Server Application Functions (SAFs).

To use a SAF, an administrator must first configure the server to load the plug-in that implements that SAF. This is typically controlled by a configuration file named magnus.conf. Once the plug-in is loaded, the administrator can configure when the server should invoke the SAF and what parameters it should be passed. This is typically controlled by a configuration file named obj.conf.

NSAPI can be compared to an earlier protocol named Common Gateway Interface (CGI). Like CGI, NSAPI provides a means of interfacing application software with a web server. Unlike CGI programs, NSAPI plug-ins run inside the server process. Because CGI programs run outside of the server process, CGI programs are generally slower than NSAPI plug-ins. However, running outside of the server process can improve server reliability by isolating potentially buggy applications from the server software and from each other.

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