Socket.IO

Real time applications like every messaging system out there and video games such as counter strike, World of Warcraft, League of Legends, you name it, rely on applications like Socket.IO. Socket.IO allows for an easier developer experience using Node.js. You're able to build a server and several listeners that connect to that server. The real-time experience is in applications emitting an event for the server to broadcast to all listeners, which is then able to care or not care about that event broadcasted.