Simple Object Access Protocol (SOAP)
SOAP/XMLP Simple Object Access Protocol (SOAP/XMLP) uses web protocols to exchange from one computer to another. SOAP/XMLP specifies how to encode an HTTP header and an XML file so that one computer program can call a program in another computer and pass it information. It also specifies how to return a response.
SOAP is a way for a program running in one kind of operating system (such as Windows 2000) to communicate with a program in the same or another kind of an operating system (such as Linux) by using the World Wide Web's Hypertext Transfer Protocol (HTTP) and its Extensible Markup Language (XML) as the mechanisms for information exchange. Since Web protocols are installed and available for use by all major operating system platforms, HTTP and XML provide an already at-hand solution to the problem of how programs running under different operating systems in a network can communicate with each other.