Redis Pub_Sub in Node.js — Real-Time Messaging Made Simple

Redis Pub/Sub (Publish/Subscribe) is a lightweight messaging system that lets applications communicate in real time. It’s widely used in chat apps, live dashboards, notifications, and microservices. In this post, you’ll learn how to implement Redis Pub/Sub in Node.js using a simple example.

Introduction

The Publish/Subscribe pattern in Redis is ideal for event-driven systems. It lets you create channels where messages are broadcasted and received by multiple subscribers in real time.

1. Install and Connect Redis

First, install the official Redis client:

npm install redis
    

Then, import and connect the client in your Node.js application:

import { createClient } from "redis";

const client = createClient({
  url: "redis://127.0.0.1:6379",
});

client.on("error", (err) => console.log("Redis Error", err));

// Connect to Redis
await client.connect();
console.log("Connected to Redis!");
    

2. Publisher — Send Messages

The publisher sends messages to a Redis channel using publish(). Here’s a simple example that sends the current time every 2 seconds.

// publisher.js
setInterval(async () => {
  const message = `Current Time: ${new Date().toISOString()}`;
  await client.publish("time_channel", message);
  console.log("📤 Published:", message);
}, 2000);
    

Every 2 seconds, a message is sent to the time_channel.

3. Subscriber — Receive Messages

In another file, create a subscriber that listens for messages on the same channel:

// receiver.js
await client.subscribe("time_channel", (message) => {
  console.log("📥 Received:", message);
});
    

Once the subscriber is connected, it will automatically receive every message published on that channel.