SOAP

SOAP is a simple XML based protocol to let applications exchange information over HTTP.
What is SOAP?
SOAP stands for Simple Object Access Protocol SOAP is a communication protocol SOAP is for communication between applications SOAP is a format for sending messages SOAP is designed to communicate via Internet SOAP is platform independent SOAP is language independent SOAP is based on XML SOAP is simple and extensible SOAP allows you to get around firewalls SOAP will be developed as a W3C standard
Why SOAP?
It is important for application development to allow Internet communication between programs.
Today's applications communicate using Remote Procedure Calls (RPC) between objects like DCOM and CORBA, but HTTP was not designed for this. RPC represents a compatibility and security problem; firewalls and proxy servers will normally block this kind of traffic. A better way to communicate between applications is over HTTP, because HTTP is supported by all Internet browsers and servers. SOAP was created to accomplish this.
SOAP provides a way to communicate between applications running on different operating systems, with different technologies and programming languages.
Building SOAP
A SOAP message is an ordinary XML document containing the following elements:
A required Envelope element that identifies the XML document as a SOAP message An optional Header element that contains header information A required Body element that contains call and response information An optional Fault element that provides information about errors that occurred while processing the message