Is Facebook's Graph API using GraphQL?

Daniel Schafer from Facebook mentioned at the GraphQL Europe conference that Facebook's GraphQL API is not available to the public. (Not to be confused with their graph API).

Their GraphQL API powers data to all facebook apps today (android, iOS, etc), and I don't think facebook have any plans of making that specific API public.

They might make their Graph API available in GraphQL at some point.

However if you want to play with a public GraphQL API, you can find some here: https://github.com/APIs-guru/graphql-apis/blob/master/README.md

Furthermore if you want to "fiddle" with setting up a GraphQL API you can try out Launchpad by Apollo: https://launchpad.graphql.com

About versioning: If you add features to your API you don't need to version it. However if you change some data output drastically, like eliminating fields, and you have clients depend on this, you would probably need to version your GraphQL API. Try to avoid this pattern.

Think of GraphQL as a client-driven development tool. If you have active clients using fields, don't remove them from API until all clients has been updated to use some other fields. Read more on versioning REST vs GraphQL here: https://www.symfony.fi/entry/versioning-an-api-in-graphql-vs-rest