Socket.IO

Socket.IO is a JavaScript library that enables real-time, bidirectional, and event-based communication between the browser and the server. It consists of:

• Server-side library for Node.js
• Client-side library for the browser (which can be also run from Node.js)

In simpler terms, Socket.IO enables live communication between computers. It simplifies the process to write messaging applications like video chat, audio chat, and text chat.

Some of the companies that use Socket.IO include Alibaba Travels, PLAID, Trello, and Patreon.