Improving REST performance is all about negotiation

Web architects must understand that resources are just consistent mappings from an identifier to some set of views on server-side state. If one view doesn’t suit your needs, then feel free to create a different resource that provides a better view (for any definition of “better”). These views need not have anything to do with how the information is stored on the server, or even what kind of state it ultimately reflects. It just needs to be understandable (and actionable) by the recipient.

--- Roy Fielding on creating new resources for REST architectures.