anonymous wrote : it's up to the process languages or products to use that block and create public API's with it. OK, so we are talking about a JPDL web service facade. anonymous wrote : another approach is not to leverage the current domain model objects (ProcessInstance, Token, ProcessDefinition,...) but instead just to define a completely separate set of limited DTO's just for the web service publication. then the web service would be fixed (not very extensible). and it would be easy to implement with JAXB since the DTO's are under control of the web service. I think this is the way to go. I cannot pull the domain model because of it's dependencies and marshalling depth and furthermore I would like to keep control of the API that's getting exposed. Otherwise any change to the domain model could easily break the web service. Another aspect that hasn't been mentioned is is versioning [1] and evolution of the web service facade. Obviously we won't have a one shot solution. [1] http://www.ibm.com/developerworks/webservices/library/ws-version/ View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4125042#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...