React, Flux, GraphQL, Hack, HHVM...? All of this and more!
XML has largely been ousted by JSON as the de-facto format for transferring data. XML remains a valid format for document annotations, but RESTful APIs serving lean JSON is where the action has been for a number of years.
Falcor is a new library open sourced by Netflix, another prominent new company giving back to Open Source. Falcor is described as a JavaScript library for efficient data fetching. It is a radically different approach from the traditional culture of building multiple endpoints.