Web Services Business Process Execution Language (WS-BPEL) defines a model and a grammar for describing the behavior of a business process based on interactions between the process and its partners.
The interaction with each partner occurs through Web Service interfaces, and the structure of the relationship at the interface level is encapsulated in what is called a partnerLink. The WS-BPEL process defines how multiple service interactions with these partners are coordinated to achieve a business goal, as well as the state and the logic necessary for this coordination.
WS-BPEL utilizes several XML specifications: WSDL, XSD, XPath, and XSLT.
