A multi-stage configuration service running in a cloud computing environment receives a transformation request from a client device. Based on a policy identified in the transformation request, the multi-stage configuration service constructs a configuration file containing key-value pairs representing settings of a requested transformation. The settings are set or constrained in accordance with zero or more facets contained in the policy that describe how an application feature is set or constrained in performing a transformation on a source file or files. The multi-stage configuration service determines, in accordance with the policy, whether the configuration file is structurally correct in view of a user-provided overriding property value and either enqueues the configuration file for a publishing agent in the cloud computing environment to perform the requested transformation or returns an error report to the client device.