The Web Services Conversation Language (WSCL) aims to supplement interface definition languages, e.g. WSDL, by describing the sequences of legal interactions that can be carried out with a particular web service interface.

The specification defines the following basic concepts to allow conversations to be described:

• DocumentTypes -- references to XML Schemas
• Interactions -- one or two way message exchanges
• Transitions -- descriptions of how to move from one interaction to another

It is expected that WSCL will be extended to describe more complex scenarios, e.g. multi-part conversations. The specification also notes that formal descriptions of interactions will allow the creation of web service frameworks that will allow the separation of messaging from core application logic.

As a processing description language, WSCL has some overlaps with the recent XML Pipeline submission.