XML Process Definition Language
The primary standards body for workflow management and business process interoperability.
The XML Process Definition Language (XPDL) is a format standardized by the Workflow Management Coalition to interchange business process definitions between different modeling tools, BPM suites, workflow engines and other software applications. XPDL defines a XML schema for specifying the declarative part of workflow.
XPDL is designed to exchange the process design, both the graphics and the semantics of a workflow business process. XPDL contains elements to hold the X and Y position of the activity nodes as well as the coordinates of points along the lines that link those nodes. XPDL provides the serialization for BPMN. This distinguishes XPDL from BPEL, which is also a process definition format, but does not contain elements to represent the graphical aspects of a process diagram and BPEL focuses exclusively on the executable aspects of the process.