Currently, the GitHub v4 API only supports POSTing the GraphQL query via
GraphQL describes how to serve queries over both HTTP GET and HTTP POST. One difference between GET and POST requests is that GET requests may be cached by HTTP proxies, while POST requests may not, because they are not idempotent.
It would be handy for some projects that make heavy use of the v3 API via caching to be able to migrate queries to v4, particularly as v4 exposes some additional information (one example: distinguishing between the direct and indirect group members). Exposing the current query interface over GET as well as POST could enable those project to make fewer queries by fetching data more efficiently. Today for these projects, the cost of an (uncached) v4 query is much higher than a dozen v3 API requests with a cache in front.