SOAP is an Object Access Protocol that Microsoft developed to replace older technologies such as DCOM (Distributed Component Object Model) and General CORBA (Object Request Broker Architecture). DCOM and CORBA are inferior because they rely on binary messages, while SOAP uses XML and works better over the Internet. SOAP relies exclusively on XML and, together with schemas, defines a strongly typed messaging structure. The main idea behind SOAP is that programs written in different programming languages and platforms can easily exchange data.
XML (eXtensible Markup Language) that provides structured information: data, documents, configuration, and more. XML was designed to be a language with a simple formal syntax to make it easy for both humans and programs to create and manage documents for use on the Internet. XML is called extensible because it does not capture the markup used in documents: you can generate markup according to the needs of a specific area, limited only by the rules of XML syntax.