In this chapter, we saw how to set data for a session, how to work with namespaces and rooms, and how to integrate with the express sessions. Here we have completed a good and working chat system. It will be a nice exercise for you to build more functionality in this, based on the concepts we learned here. Some interesting features to build can be user exist alert, user list for the rooms, private chats, and so on. In the next chapter, we will take a look at the socket.io protocol and understand its workings.