For me, GraphQL is great tool but it take a lot of effort to migrate in case you already has a full REST API set. So, I choose a different approach, that is introducing a Batch Request API. Client can execute several requests with single network call and only get back a part of response they care about. With a small lib I wrote & full REST API set, you have pretty much all GraphQL function.

Hi. I'm the author of JsonBatch library - an Engine to run batch request with JSON based REST APIs. I have setup a small site so you can test out JsonBatch's feature.