Building a Chat Application using Upstash Kafka, Redis and Next.js

The blog post details the creation of a messaging application utilizing Upstash Redis for message storage and Upstash Kafka for message passing. It explains how users can register multiple clients, each with a unique username, and access past messages in a chat room. The application architecture involves a WebSocket connection linking clients to a message server, which routes messages to a Kafka broker and stores them in Redis for historical access. The server employs Node.js and the ws library to handle message flow, and the react-use-websocket library is used on the client side to manage WebSocket connections. The post also covers the deployment process using Fly.io and provides suggestions for improvements, such as retaining chat history upon page reloads and implementing multiple chat rooms and message servers for scalability.