I've also used PostgREST successfully. It was first meant as a tool for rapid prototyping, but it worked so well that we kept it. We ended up separating the dat

I've also used PostgREST successfully. It was first meant as a tool for rapid prototyping, but it worked so well that we kept it. We ended up separating the database into a schema called api, consisting only of views of the core domain tables available in the data schema. PostgREST exposed the api-schema only. This way we could model a stable interface and vary the low-level details of the domain tables. Writes were handled by instead-of triggers on the views. So far this has been the quickest way of building an API that I know of.