As with any new tech it can be overwhelming and confusing how all the parts work together. Especially with the combo of Relay and GraphQL. Hopefully this post will help demystify some things in Relay.

What is Relay: Data driven JavaScript framework used to efficiently handle data communication between a React and a GraphQL server.

Why use it: One typical issue found in an SPA are the number of network calls made to render a page. Quickly this starts to affect your server performance because the requests made can be high. Relay is focused around efficient network calls helping to mitigate this issue. Another good feature is the queries are close to the components making it obvious the data requirements.