1. A computer-readable medium containing code executable by a processor to generate a workflow engine comprising: a Petri net domain model comprising a set of objects, wherein each object represents a particular type of element of a Petri net model; and one or more runtime components adapted for: reading source code representing a particular workflow, wherein the source code indicates elements of the particular workflow and connectors between elements of the particular workflow to sequence the elements of the particular workflow; loading the particular workflow into memory by mapping each element of the particular workflow to one or more objects of the set of objects and by mapping each connector of the particular workflow to one or more objects of the set of objects based on rules governing the Petri net model; and executing the particular workflow loaded into the memory.