Provides benefits of REST but allows adaptation to WS clients. This would still require support for the authorization mechanism to get keys, but could deliver the data for those users in a single batch, periodically (say, once per day), in the same format as the REST version. (Or, possibly, a simplified format without Atom or AtomPub elements). This would not allow on-demand requests, or flows from 3rd Parties to Utilities, but may be sufficient for some clients.