Introduction to WebSockets and Real-Time Communication

Polling a task board every 2 seconds costs 30 HTTP requests a minute for each open browser tab, and most of those requests return nothing new. HTTP works this way because the client always speaks first: the server can answer a request, but it cannot start a conversation. A chat, a live notification or a shared task board needs the opposite, where the server sends news the moment it happens.

This chapter adds a live project chat to the task app. This first lesson explains the protocol that makes it possible and runs a small server and client without Express.