Web services are client and server applications that communicate over
the World Wide Web’s (WWW) HyperText Transfer Protocol (HTTP). As
described by the World Wide Web Consortium (W3C), web services provide a
standard means of interoperating between software applications running
on a variety of platforms and frameworks. Web services are characterized
by their great interoperability and extensibility as well as their
machine-processable descriptions, thanks to the use of XML. Web services
can be combined in a loosely coupled way to achieve complex operations.
Programs providing simple services can interact with each other to
deliver sophisticated added-value services.