In this chapter, we're going to see how we can use the tools we've covered so far to build real-time applications for the Web. However, before diving into it, one of the first questions you may want answered is, "what exactly is a real-time web application?"
A real-time web application can be defined as any kind of web-facing software that allows clients (usually users) to receive information as soon as it gets published. In other words, it's a software application that functions within a timeframe that the user senses as immediate or current. In these types of software, latency must be extremely low, usually in the range of milliseconds.