PostGraphile is built on Graphile Engine which is completely backend-independent (like GraphQL itself). This is what we use in PostGraphile for the "look-ahead" functionality, allowing you to build a database/API/backend query that represents a full GraphQL query as one action. You can read more about it here, though it's currently not as well documented as PostGraphile itself. https://www.graphile.org/graphile-build/
