In this chapter, you learned how to build a fully-feature Hackernews clone with React and Relay. You implemented several features, such as displaying a list of links, login functionality, creating new links, voting on links as well as realtime updates with GraphQL subscriptions.
Relay is an extremely powerful GraphQL client that’s developed by Facebook. It incorporates all major learnings that Facebook gathered since they started using GraphQL in 2012. Above all, Relay is heavily optimized for performance to minimize the amount of data that’s transferred over the network and to work well on low-powered mobile devices.
There’s a notable learning curve for developers when getting started with Relay. The release of the 1.0 version, called Relay Modern, generally made Relay more approachable and eliminated many issues that developer used to have with Relay Classic. However, the scarce documentation and lack of general examples still make it a challenge to adopt Relay in a project.