GraphQL will probably overtake REST in a few years time:

https://trends.google.com/trends/explore?date=today%205-y&q=...

If you were building a large scale API now, having duplicate data at each resource (eg, avatar icon URLs in /feed) or requiring users to cross reference multiple resources for a single simple task (eg GETing /users and /feed to draw a simple timeline with user avatars) is a hassle and there's no real reason to force yourself or your API consumers through it.

The GraphQL specification is here: https://facebook.github.io/graphql/