In this chapter, we have created a real-time client/server communication channel using Socket.IO, used Redis as a backend to scale a real-time application horizontally, integrated Socket.IO with Express middleware, and organized our application using Socket.IO namespaces and rooms.
As the network connectivity of our application is becoming more complicated, it's more important to test the application on a web server outside of the development or CI environment. In the next chapter, we'll look at how to deploy our application to the web.