Not as far as I know, but I guess the pieces of the puzzle are there. You will have to do a lot of work by yourself. The future Graphql-module for Mendix is very likely pretty similar to the OQL module. Take that as a start and you might be able to generate the module by yourself. The OQL-module is the closest thing to Graphql-support that Mendix has got at this moment.
application/json content type – So, you can utilize Mendix’s REST Service to consume or produce.