BullMQ Has a Free Job Queue for Node.js — Here's How to Use It

#node #queue #redis #backend

Processing emails, resizing images, or scraping data synchronously blocks your API. BullMQ gives you reliable background jobs with retries, priorities, rate limiting, and a dashboard — all backed by Redis.

What Is BullMQ?

BullMQ is a Node.js message queue and job scheduling library built on Redis. It handles background processing, delayed jobs, rate limiting, and job dependencies.

Quick Start

npm install bullmq

import { Queue, Worker } from 'bullmq';

// Create a queue
const emailQueue = new Queue('emails', {
  connection: { host: 'localhost', port: 6379 }
});

// Add jobs
await emailQueue.add('welcome', {
  to: 'user@example.com',
  subject: 'Welcome!',
  template: 'welcome',
});

// Process jobs
const worker = new Worker('emails', async (job) => {
  console.log(`Sending ${job.data.subject} to ${job.data.to}`);
  await sendEmail(job.data);
}, {
  connection: { host: 'localhost', port: 6379 }
});

worker.on('completed', (job) => console.log(`Job ${job.id} completed`));
worker.on('failed', (job, err) => console.log(`Job ${job.id} failed: ${err}`));

Key Features

Retries with Backoff

await queue.add('process', data, {
  attempts: 5,
  backoff: {
    type: 'exponential',
    delay: 1000, // 1s, 2s, 4s, 8s, 16s
  },
});

Delayed Jobs

// Process in 30 minutes
await queue.add('reminder', data, {
  delay: 30 * 60 * 1000,
});

Cron/Repeatable Jobs

await queue.add('daily-report', data, {
  repeat: {
    pattern: '0 9 * * *', // Every day at 9 AM
  },
});

Rate Limiting

const worker = new Worker('api-calls', processor, {
  limiter: {
    max: 100,       // Max 100 jobs
    duration: 60000, // Per minute
  },
});

Job Priority

await queue.add('task', urgentData, { priority: 1 }); // High
await queue.add('task', normalData, { priority: 5 }); // Normal
await queue.add('task', lowData, { priority: 10 });    // Low

Job Progress

const worker = new Worker('upload', async (job) => {
  for (let i = 0; i < 100; i++) {
    await processChunk(i);
    await job.updateProgress(i + 1);
  }
});

// Listen for progress
const job = await queue.add('upload', data);
job.on('progress', (progress) => console.log(`${progress}%`));

Dashboard (Bull Board)

import { createBullBoard } from '@bull-board/api';
import { BullMQAdapter } from '@bull-board/api/bullMQAdapter';
import { ExpressAdapter } from '@bull-board/express';

const serverAdapter = new ExpressAdapter();
createBullBoard({
  queues: [new BullMQAdapter(emailQueue), new BullMQAdapter(uploadQueue)],
  serverAdapter,
});

app.use('/admin/queues', serverAdapter.getRouter());

Why BullMQ

Feature	BullMQ	Celery	SQS
Language	Node.js	Python	Any
Backend	Redis	Redis/RabbitMQ	AWS
Dashboard	Bull Board	Flower	Console
Rate limiting	Built-in	Plugin	Manual
Priorities	Yes	Yes	Limited
Cost	Free + Redis	Free	Per-message