This is an example of GraphQL server supporting Relay written with Play framework and Sangria, it also uses webpack for client side asset generation.
This example is based on the Relay Star Wars example. You can find more info here.
It also serves as a playground - on the right hand side you see a textual representation of the GraphQL schema which is implemented on the server and that you can query here. On the left hand side you can execute a GraphQL query and see the results of its execution.
It's available here:
http://try-relay.sangria-graphql.org
This is just a small demonstration. It really gets interesting when you start to play with the schema on the server side. Fortunately it's pretty easy to do. Since it's a simple Play application using webpack, all it takes to start playground locally and start playing with the schema is this:
$ git clone https://github.com/sangria-graphql/sangria-relay-playground.git
$ cd sangria-relay-playground
$ npm install
$ sbt runNow you are ready to go to http://localhost:9000 for the playground or to http://localhost:9000/starwars for the minimal Star Wars example.