it’s a database, where the way you talk to it is via HTTP and GraphQL, so it’s:
client --> backend server --> dgraph --> disk
This feature is built into dgraph the database itself. So unlike Postgres where you might require something like Postgraphile as a service in front of the database, it just is built in.
The GraphQL API server is a hosted service called slash graphql, which is a combination of dgraph (the database), and a bunch of operational stuff like load balancers which form the “server”.