Understanding the SOAP XML protocol

To understand SOAP you should have knowledge of XML. This would help you a lot to interpret the different elements in SOAP. SOAP is a Simple Object Access Protocol used for communication between applications. XML is used in SOAP message for communication. The communication happens through internet.

When we say internet the communication protocol that is used is naturally HTTP. The current way of communication between applications is RPC where there is no compatibility for HTTP. SOAP can be used in HTTP and through firewalls.

HTTP is supported by all the browsers. These are the advantages of using SOAP. It is language and platform independent since the message is passed in the XML format.

A SOAP message is an XML document that has certain elements in it. Elements like Envelope and Body are compulsory and optional elements in the SOAP document are Header and Fault.

The namespace http://www.w3.org/2001/12/soap-envelope is where all these elements are declared.