SOAP is an object-oriented, Internet-based protocol for exchanging information between applications in a distributed environment. Box  provides a good basic introduction to SOAP with some examples. SOAP is independent of the programming language, platform or transport mechanism used for the exchange. SOAP's interoperability arises from a simple syntax based on XML (Extensible Markup Language ). Although HTTP (Hypertext Transfer Protocol) is the most widely used transport layer for SOAP packets, which are XML documents, other protocols like SMTP or FTP can also be used. The SOAP message exchange model consists of one-way transmissions from sender to receiver which can be combined to be used as a request/response pattern. SOAP messages rely on XML Namespaces  and the XML Schema definition language . The XML encoding makes SOAP messages simple to read and parseable by humans and machines alike, as testified by the plethora of XML parsers in various languages running on multiple platforms.