You must be aware of web services where you provide a url and when some hit those url they get some data. Now say there is a change in that data and you want to be aware of that change then what will you do. We can use polling that is keep calling the url
![Web Sockets and how they solve the problem caused by pooling.](https://i1.wp.com/www.learnsteps.com/wp-content/uploads/2017/09/latency-comparison.gif?resize=504%2C360&ssl=1)