Unlike other frameworks, AEM is resource-based, and the resource defines
the contract in the first place, but not the code. The most API-like
thing, which comes close to the idea of other frameworks are
Content-Fragments because there the structure and the content is clear.
Also the SlingModel Exporter gives you the chance to control the details
of the payload you get. So when you use AEM as a remote system (in a
kind of headless way), these are the APIs you should look for. Jörg