What do you mean by "many?" While I like Relay, I've almost never seen Relay used in the wild. It's sad as it's quite an elegant concept; just as you define your props for your React component, you define your "props" coming from the server as well, through the GraphQL notation. I've been looking at ways to combine both concepts so that there is no client- or server-side state at all, it's all just state, from a cache that determines whether to refetch from the server or to keep the state local.