1. A system comprising: base metadata configured to characterize data processing logic within a software application; custom metadata configured to define a variant of the software application including custom data processing logic, the custom metadata data being configured to be overlaid on the base metadata and to inherit attributes of the base metadata; a context evaluator configured to overlay the custom metadata on the base metadata in response to a request to execute the software application received from an end user, responsive to an execution context; and a runtime metadata interpreter configured to generate executable instructions using the base metadata and overlaid custom metadata at runtime.