> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/taskforcesh/bullmq/llms.txt
> Use this file to discover all available pages before exploring further.

# What is BullMQ

> Learn about BullMQ, a fast and robust Redis-based distributed queue system for Node.js

BullMQ is a [Node.js](https://nodejs.org) library that implements a fast and robust queue system built on top of [Redis](https://redis.io). It helps resolve many modern microservices architecture challenges by providing a reliable message queue system.

## Overview

The fastest, most reliable, Redis-based distributed queue for Node. Carefully written for rock solid stability and atomicity.

BullMQ is designed to fulfill the following goals:

* **Exactly once semantics** - Attempts to deliver every message exactly one time, but will deliver at least once in the worst case scenario
* **Horizontal scalability** - Easy to scale by adding more workers for processing jobs in parallel
* **Consistency** - Reliable and consistent job processing
* **High performance** - Achieves the highest possible throughput from Redis by combining efficient Lua scripts and pipelining

<Note>
  View the repository, see open issues, and contribute back on [GitHub](https://github.com/taskforcesh/bullmq)!
</Note>

## Core Concepts

BullMQ is based on 4 main classes that together can be used to resolve many different problems:

<CardGroup cols={2}>
  <Card title="Queue" icon="list">
    Used for adding jobs to the queue and basic queue manipulation such as pausing, cleaning, or getting data from the queue.
  </Card>

  <Card title="Worker" icon="gear">
    Instances capable of processing jobs. You can have many workers running in the same process, separate processes, or different machines.
  </Card>

  <Card title="QueueEvents" icon="bolt">
    Used to listen to global events like job completions, failures, and progress updates.
  </Card>

  <Card title="FlowProducer" icon="diagram-project">
    Used for creating jobs with parent-child dependencies and complex job workflows.
  </Card>
</CardGroup>

## Key Features

BullMQ provides a comprehensive set of features for queue management:

* **Minimal CPU usage** - Polling-free design for optimal performance
* **Distributed execution** - Job execution based on Redis for distributed systems
* **Job ordering** - Support for LIFO and FIFO job processing
* **Priorities** - Prioritize important jobs over others
* **Delayed jobs** - Schedule jobs to be processed at a future time
* **Repeatable jobs** - Schedule jobs according to cron specifications
* **Automatic retries** - Failed jobs can be automatically retried
* **Concurrency control** - Set concurrency per worker
* **Sandboxed processing** - Threaded (sandboxed) processing functions for isolation
* **Automatic recovery** - Recover from process crashes
* **Parent-Child dependencies** - Create complex job workflows with dependencies
* **Rate limiting** - Control the rate of job processing
* **Job events** - Listen to various job lifecycle events

## Why Use Message Queues?

If you're new to message queues, you may wonder why they are needed. Queues can solve many different problems elegantly:

* **Smoothing processing peaks** - Handle traffic spikes without overwhelming your system
* **Microservices communication** - Create robust communication channels between services
* **Offloading heavy work** - Distribute heavy workloads from one server to many workers
* **Background processing** - Handle time-consuming tasks asynchronously
* **Job scheduling** - Schedule tasks to run at specific times or intervals
* **Reliability** - Ensure jobs are processed even if services temporarily go down

## Used By

BullMQ is trusted by many organizations, including:

* Microsoft (Lage build system)
* Vendure (E-commerce framework)
* Datawrapper (Data visualization tool)
* NestJS (Progressive Node.js framework)
* Langfuse (LLM engineering platform)
* Novu (Notification infrastructure)
* NocoDB (Open source Airtable alternative)
* Infisical (Secret management platform)

## Next Steps

<CardGroup cols={2}>
  <Card title="Installation" icon="download" href="/installation">
    Get started by installing BullMQ in your project
  </Card>

  <Card title="Quick Start" icon="rocket" href="/quick-start">
    Create your first queue and worker in minutes
  </Card>

  <Card title="Architecture" icon="sitemap" href="/architecture">
    Understand how BullMQ works under the hood
  </Card>

  <Card title="API Reference" icon="code" href="https://api.docs.bullmq.io">
    Explore the complete API documentation
  </Card>
</CardGroup>