SOAP is the Simple Object Access Protocol used XML to define a protocol for the exchange of information in distributed computing environments. SOAP consists of three components:
1. An envelope
2. A set of encoding rules and
3. A convention for representing remote procedure calls.
Unless experience with SOAP is a direct requirement for the open position, knowing the specifics of the protocol, or how it can be used in conjunction with HTTP, is not as important as identifying it as a natural application of XML.