How to build real-time applications using WebSockets with AWS API Gateway and Lambda

Recently AWS has announced the launch of a widely-requested feature: WebSockets for Amazon API Gateway. With WebSockets, we are able to create a two-way communication line which can be used in many scenarios like real-time applications. This brings up the question: what are real-time applications? So let’s first answer that question.

Most of the applications that are currently operational use client-server architecture. In client-server architecture, the client sends the requests over the Internet using network communication and then the server processes that request and sends the response back to the client.

Here you can see that it is the client that starts off the communication with the server. So first the client initiates the communication and the server responds to the request sent by the server. So what if the server wants to start off the communication and push responses without the client requesting them first? That is where real-time applications come into the play.

Real-time applications are applications where the server gets the ability to push to the clients without the client requesting data first. Assume we have a chat application where two chat clients can communicate via a server. In this situation, it is a waste if all the chat…