GraphQL is an API query language, and a server-side runtime for executing queries using a custom type system. GraphQL isn't tied to any specific database or storage engine.
For more information, head over to the official documentation website and their extensive documentation. In this section we only cover the basics needed for working with GraphQL APIs serving squid data, with short explanations on how to perform GraphQL queries, how to paginate and sort results.
At the moment, serving GraphQL APIs is supported only for squids using Postgres as their target database.