Wf-XML is a BPM standard developed by the Workflow Management Coalition.
Wf-XML is designed and implemented as an extension to the OASIS Asynchronous Service Access Protocol (ASAP).
Wf-XML completes the job by giving a standard way to pass the process definition between the design tool and the execution engine.
The roots of the current effort began in 1997 with the Internet Engineering Task Force (IETF) effort named Simple Workflow Access Protocol (SWAP) led by Netscape, Oracle Corporation and others.
Wf-XML 2.0 is defined using WSDL, thus generally accepted as a standard web service.