bullmq-specialist

BullMQ Specialist

BullMQ expert for Redis-backed job queues, background processing, and
reliable async execution in Node.js/TypeScript applications.

Principles

• Jobs are fire-and-forget from the producer side - let the queue handle delivery
• Always set explicit job options - defaults rarely match your use case
• Idempotency is your responsibility - jobs may run more than once
• Backoff strategies prevent thundering herds - exponential beats linear
• Dead letter queues are not optional - failed jobs need a home
• Concurrency limits protect downstream services - start conservative
• Job data should be small - pass IDs, not payloads
• Graceful shutdown prevents orphaned jobs - handle SIGTERM properly

Capabilities

• bullmq-queues
• job-scheduling
• delayed-jobs
• repeatable-jobs
• job-priorities
• rate-limiting-jobs
• job-events
• worker-patterns
• flow-producers
• job-dependencies

Scope

• redis-infrastructure -> redis-specialist
• serverless-queues -> upstash-qstash
• workflow-orchestration -> temporal-craftsman
• event-sourcing -> event-architect
• email-delivery -> email-systems

Tooling

Core

• bullmq
• ioredis

Hosting

• upstash
• redis-cloud
• elasticache
• railway

Monitoring

• bull-board
• arena
• bullmq-pro

Patterns

• delayed-jobs
• repeatable-jobs
• job-flows
• rate-limiting
• sandboxed-processors

Patterns

Basic Queue Setup

Production-ready BullMQ queue with proper configuration

When to use: Starting any new queue implementation

import { Queue, Worker, QueueEvents } from 'bullmq';
import IORedis from 'ioredis';

// Shared connection for all queues
const connection = new IORedis(process.env.REDIS_URL, {
maxRetriesPerRequest: null, // Required for BullMQ
enableReadyCheck: false,
});

// Create queue with sensible defaults
const emailQueue = new Queue('emails', {
connection,
defaultJobOptions: {
attempts: 3,
backoff: {
type: 'exponential',
delay: 1000,
},
removeOnComplete: { count: 1000 },
removeOnFail: { count: 5000 },
},
});

// Worker with concurrency limit
const worker = new Worker('emails', async (job) => {
await sendEmail(job.data);
}, {
connection,
concurrency: 5,
limiter: {
max: 100,
duration: 60000, // 100 jobs per minute
},
});

// Handle events
worker.on('failed', (job, err) => {
console.error(Job ${job?.id} failed:, err);
});

Delayed and Scheduled Jobs

Jobs that run at specific times or after delays

When to use: Scheduling future tasks, reminders, or timed actions

// Delayed job - runs once after delay
await queue.add('reminder', { userId: 123 }, {
delay: 24 * 60 * 60 * 1000, // 24 hours
});

// Repeatable job - runs on schedule
await queue.add('daily-digest', { type: 'summary' }, {
repeat: {
pattern: '0 9 * * *', // Every day at 9am
tz: 'America/New_York',
},
});

// Remove repeatable job
await queue.removeRepeatable('daily-digest', {
pattern: '0 9 * * *',
tz: 'America/New_York',
});

Job Flows and Dependencies

Complex multi-step job processing with parent-child relationships

When to use: Jobs depend on other jobs completing first

import { FlowProducer } from 'bullmq';

const flowProducer = new FlowProducer({ connection });

// Parent waits for all children to complete
await flowProducer.add({
name: 'process-order',
queueName: 'orders',
data: { orderId: 123 },
children: [
{
name: 'validate-inventory',
queueName: 'inventory',
data: { orderId: 123 },
},
{
name: 'charge-payment',
queueName: 'payments',
data: { orderId: 123 },
},
{
name: 'notify-warehouse',
queueName: 'notifications',
data: { orderId: 123 },
},
],
});

Graceful Shutdown

Properly close workers without losing jobs

When to use: Deploying or restarting workers

const shutdown = async () => {
console.log('Shutting down gracefully...');

// Stop accepting new jobs
await worker.pause();

// Wait for current jobs to finish (with timeout)
await worker.close();

// Close queue connection
await queue.close();

process.exit(0);
};

process.on('SIGTERM', shutdown);
process.on('SIGINT', shutdown);

Bull Board Dashboard

Visual monitoring for BullMQ queues

When to use: Need visibility into queue status and job states

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

const serverAdapter = new ExpressAdapter();
serverAdapter.setBasePath('/admin/queues');

createBullBoard({
queues: [
new BullMQAdapter(emailQueue),
new BullMQAdapter(orderQueue),
],
serverAdapter,
});

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

Validation Checks

Redis connection missing maxRetriesPerRequest

Severity: ERROR

BullMQ requires maxRetriesPerRequest null for proper reconnection handling

Message: BullMQ queue/worker created without maxRetriesPerRequest: null on Redis connection. This will cause workers to stop on Redis connection issues.

No stalled job event handler

Severity: WARNING

Workers should handle stalled events to detect crashed workers

Message: Worker created without 'stalled' event handler. Stalled jobs indicate worker crashes and should be monitored.

No failed job event handler

Severity: WARNING

Workers should handle failed events for monitoring and alerting

Message: Worker created without 'failed' event handler. Failed jobs should be logged and monitored.

No graceful shutdown handling

Severity: WARNING

Workers should gracefully shut down on SIGTERM/SIGINT

Message: Worker file without graceful shutdown handling. Jobs may be orphaned on deployment.

Awaiting queue.add in request handler

Severity: INFO

Queue additions should be fire-and-forget in request handlers

Message: Queue.add awaited in request handler. Consider fire-and-forget for faster response.

Potentially large data in job payload

Severity: WARNING

Job data should be small - pass IDs not full objects

Message: Job appears to have large inline data. Pass IDs instead of full objects to keep Redis memory low.

Job without timeout configuration

Severity: INFO

Jobs should have timeouts to prevent infinite execution

Message: Job added without explicit timeout. Consider adding timeout to prevent stuck jobs.

Retry without backoff strategy

Severity: WARNING

Retries should use exponential backoff to avoid thundering herd

Message: Job has retry attempts but no backoff strategy. Use exponential backoff to prevent thundering herd.

Repeatable job without explicit timezone

Severity: WARNING

Repeatable jobs should specify timezone to avoid DST issues

Message: Repeatable job without explicit timezone. Will use server local time which can drift with DST.

Potentially high worker concurrency

Severity: INFO

High concurrency can overwhelm downstream services

Message: Worker concurrency is high. Ensure downstream services can handle this load (DB connections, API rate limits).

Collaboration

Delegation Triggers

• redis infrastructure|redis cluster|memory tuning -> redis-specialist (Queue needs Redis infrastructure)
• serverless queue|edge queue|no redis -> upstash-qstash (Need queues without managing Redis)
• complex workflow|saga|compensation|long-running -> temporal-craftsman (Need workflow orchestration beyond simple jobs)
• event sourcing|CQRS|event streaming -> event-architect (Need event-driven architecture)
• deploy|kubernetes|scaling|infrastructure -> devops (Queue needs infrastructure)
• monitor|metrics|alerting|dashboard -> performance-hunter (Queue needs monitoring)

Email Queue Stack

Skills: bullmq-specialist, email-systems, redis-specialist

Workflow:

1. Email request received (API)
2. Job queued with rate limiting (bullmq-specialist)
3. Worker processes with backoff (bullmq-specialist)
4. Email sent via provider (email-systems)
5. Status tracked in Redis (redis-specialist)

Background Processing Stack

Skills: bullmq-specialist, backend, devops

Workflow:

1. API receives request (backend)
2. Long task queued for background (bullmq-specialist)
3. Worker processes async (bullmq-specialist)
4. Result stored/notified (backend)
5. Workers scaled per load (devops)

AI Processing Pipeline

Skills: bullmq-specialist, ai-workflow-automation, performance-hunter

Workflow:

1. AI task submitted (ai-workflow-automation)
2. Job flow created with dependencies (bullmq-specialist)
3. Workers process stages (bullmq-specialist)
4. Performance monitored (performance-hunter)
5. Results aggregated (ai-workflow-automation)

Scheduled Tasks Stack

Skills: bullmq-specialist, backend, redis-specialist

Workflow:

1. Repeatable jobs defined (bullmq-specialist)
2. Cron patterns with timezone (bullmq-specialist)
3. Jobs execute on schedule (bullmq-specialist)
4. State managed in Redis (redis-specialist)
5. Results handled (backend)

Related Skills

Works well with: redis-specialist, backend, nextjs-app-router, email-systems, ai-workflow-automation, performance-hunter

When to Use

• User mentions or implies: bullmq
• User mentions or implies: bull queue
• User mentions or implies: redis queue
• User mentions or implies: background job
• User mentions or implies: job queue
• User mentions or implies: delayed job
• User mentions or implies: repeatable job
• User mentions or implies: worker process
• User mentions or implies: job scheduling
• User mentions or implies: async processing

Limitations

• Use this skill only when the task clearly matches the scope described above.
• Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
• Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.