1. A method for simulation comprising: sending a stateless message to instantiate a stateful simulation object for a selected backend application of a service-oriented architecture system; receiving a confirmation of instantiation of the stateful simulation object, the confirmation including a simulation object identifier that identifies the stateful simulation object; sending a stateless activity request message that includes the simulation object identifier to cause an activity to be executed in the backend application; and storing a result of the execution of the activity in the stateful simulation object.