GraphQLController.cs

[Route("api/graphql")]
public class GraphQLController : Controller
{
    private readonly GraphQLQuery _graphQLQuery;
    private readonly IDocumentExecuter _documentExecuter;
    private readonly ISchema _schema;

    public GraphQLController(GraphQLQuery graphQLQuery, IDocumentExecuter documentExecuter, ISchema schema)
    {
        _graphQLQuery = graphQLQuery;
        _documentExecuter = documentExecuter;
        _schema = schema;
    }

    [HttpPost]
    public async Task<IActionResult> Post([FromBody] GraphQLParameter query)
    {
        var executionOptions = new ExecutionOptions { Schema = _schema, Query = query.Query, UserContext = User };
        var result = await _documentExecuter.ExecuteAsync(executionOptions).ConfigureAwait(false);

        if (result.Errors?.Count > 0)
        {
            return BadRequest(result.Errors);
        }

        return Ok(result);
    }
}