WebSockets make it possible to have interactive, two-way communication sessions between the user's browser and a server. With this API, you can receive event-driven messages without having to poll the server for updates. This makes WebSockets a powerful and efficient tool for building interactive websites.
Libraries such as Socket.IO make it easy to integrate WebSockets into the front-end and back-end of a site. In this course, Tuts+ instructor Daniel Stern will show you how to build a real-time link-sharing application that uses Express and Socket.IO.