I appreciate your inquiry about iSAPI. iSAPI stands for Internet Server Application Programming Interface. It is a technology that allows developers to create web server extensions in Windows environments typically used with Microsoft's Internet Information Services (IIS). iSAPI extensions are similar to CGI scripts but offer better performance due to their ability to maintain persistent connections to the web server. This makes them more efficient for processing multiple requests compared to CGI scripts which create a new process for each request. Developers can use iSAPI to create custom server-side applications or services that extend the functionality of a web server. These extensions can handle dynamic content generation authentication logging caching and more. Examples of iSAPI extensions include custom authentication modules URL rewriting modules or even support for custom protocols. Here's a simple example of how an iSAPI extension might look in C++: #include #include class MyHttpModule : public CHttpModule { public: REQUEST_NOTIFICATION_STATUS OnBeginRequest(IN IHttpContext* pHttpContext IN IHttpEventProvider* pProvider) { // Your custom logic here return RQ_NOTIFICATION_CONTINUE; } }; // Register the module HRESULT WINAPI RegisterModule(DWORD dwServerVersion IHttpModuleRegistrationInfo* pModuleInfo IHttpServer* pHttpServer) { MyHttpModule* pModule = new MyHttpModule(); return pModuleInfo->SetRequestNotifications(pModule RQ_BEGIN_REQUEST); } Overall iSAPI provides a powerful way to extend web server functionality and create custom applications or services tailored to specific needs. If you have any more specific questions or need further examples feel free to ask!