A facility is described for enabling workflow applications. The facility receives a request to identify an optimized resource list that identifies resources capable of performing a workflow process task. The workflow process task can be associated with a document type relating to a document associated with a workflow envelope. The workflow envelope can store multiple documents of at different document types. The facility includes a workflow engine and a simulation engine. The workflow engine performs workflow process tasks based on the tasks identified in the workflow envelope. The simulation engine can employ modeling and historical data from a workflow metrics data source to generate the optimized resource list and identify identifying resources matching the workflow process tasks identified in the workflow envelope. The simulation engine can be used to model the workflow process to adapt, modify or otherwise control the workflow.