[akrymski]

The benefit of selecting specific fields is easily achieved in REST, see how PostgREST does it for an example of passing a select parameter listing the fields to include or exclude.

The negative side effects of selecting specific fields include limited caching - in most cases it makes sense to return full records from the server for further filtering in the client, with the added benefit of free caching for GET requests provided by the browser. I find that gzipping JSON works so well in practice that it's rarely worth selecting specific fields. Using a binary protocol as an alternative to JSON would be more advantageous imho.