Windows HTTP Services
WinHTTP supports desktop client applications, Windows services, and Windows server-based applications.
WinHTTP is not recommended for applications built on the Microsoft .NET Framework, because .NET Framework applications should use the networking facilities in the System.Net classes.
WinHTTP offers both a C/C++ application programming interface (API) and a Component Object Model (COM) automation component suitable for use in Active Server Pages (ASP) based applications.
A basic understanding of the HTTP protocol is important to use either interface.
WinHTTP 5.1 offers improvements over version 5.0. It is included in the operating system. For more information about new features, see What's New in WinHTTP 5.1 and What's New in Windows Server 2008 and Windows Vista.
Important The WinHTTP 5.0 download is no longer available. As of October 1, 2004, Microsoft removed the WinHTTP 5.0 SDK download from MSDN and terminated product support for version 5.0.