Graphql Query/Mutation

Sample JSON Body to Reference:
{ "query": "mutation { setHello(message: \"Hello from the mutation!\") }" } { "query": "{ hello }" } { "query": "query { getUser(username: \"john_doe\") { id username email created_at } }" } { "query": "query { userExists(username: \"john_doe\") }" } { "query": "query userExists { userExists(username: \"black\") }" } { "operation": "getUsername", "username": "black", "query": "query getUser($username: String!) { getUser(username: $username) { id username email created_at } }", "variables": { "username": "black" } }