My 2c are that if I am building a fully featured REST API, I would build it on top of GraphQL. Depending on the audience, GraphQL can be overwhelming (especially if you adopt advanced conventions like relay). However, GQL has a lot of benefits as an intermediate layer between REST and your business logic.
In practice, your REST layer would call a GQL query/mutation. You can leverage GQL’s resolvers for serialization, backwards compat for changes in business logic, N+1 is handled through Absinthe helpers / dataloader, and “expanded” REST fields are just conditional fragments on a query. A simple utility can convert GQL errors nested in the response into HTTP error codes. So your users are calling REST urls, but it’s actually GQL under the hood. And then, of course you could expose your GQL endpoint as well…
