3 Answers
There is a C++ GraphQL parser. It doesn’t provide all the features of the Apollo client but it eases C++ GQL handling a lot.
Apollo Client has a good set of caching features, but if you don’t need those features, you can just use your favorite http library (libcurl, or Boost.Beast, or Casanova maybe) to send a POST with the text of your graphql query or mutation. The response will be the same sort or response that you would see in the GraphiQL console.
Currently, there’s not an Apollo Client implementation for C++ or C#. However, I see the benefit of having such a library around. Is anybody interested in translating Apollo Client 2 for C++ and C#? If so, please start a bounty, and link it in a comment!
Microsoft has open sourced a GraphQL server & client C++ project: https://github.com/microsoft/cppgraphqlgen
It has a client which does parse and abstract the value types.