EMQX

intermediate

Scalable MQTT broker for IoT.

Overview

EMQX is a high-performance, open-source MQTT broker designed specifically for IoT and real-time messaging applications. Originally developed by EMQ Technologies, EMQX has evolved into one of the most scalable MQTT brokers available, capable of handling millions of concurrent connections while maintaining low latency and high throughput. Built on Erlang/OTP, it leverages the actor model for exceptional fault tolerance and distributed computing capabilities. This Docker deployment provides a complete EMQX broker instance with multiple protocol endpoints and a comprehensive web dashboard for monitoring and management. The configuration exposes standard MQTT ports (1883), secure MQTT over SSL (8883), WebSocket connections (8083/8084), and the administrative dashboard (18083), making it suitable for both development and production IoT environments. EMQX excels in scenarios requiring massive device connectivity, real-time data streaming, and complex message routing rules. The broker's built-in rule engine allows for real-time data processing and transformation without requiring external components. This makes EMQX particularly valuable for IoT platform developers, industrial automation companies, and organizations building large-scale device management systems where message reliability and horizontal scalability are critical requirements.

Key Features

Massive concurrent connection support with millions of MQTT clients per node
Built-in rule engine for real-time message processing, filtering, and transformation
Multiple protocol support including MQTT 3.1.1, MQTT 5.0, WebSocket, and CoAP
Hot configuration updates without service interruption or connection drops
Advanced authentication and authorization with JWT, OAuth 2.0, and custom plugins
Message persistence and replay capabilities for reliable delivery guarantees
Comprehensive monitoring and alerting through built-in metrics and webhook notifications
Plugin architecture supporting custom extensions for databases, message queues, and cloud services

Common Use Cases

1IoT device management platforms requiring high-volume sensor data collection
2Industrial automation systems with real-time machine-to-machine communication
3Smart city infrastructure connecting traffic lights, environmental sensors, and public displays
4Vehicle telematics platforms tracking fleet location, diagnostics, and driver behavior
5Home automation hubs managing smart thermostats, security cameras, and lighting systems
6Real-time chat applications and mobile push notification services
7Financial trading platforms requiring low-latency market data distribution

Prerequisites

Minimum 2GB RAM for basic deployment, 4GB+ recommended for production workloads
Available ports 1883, 8083, 8084, 8883, and 18083 on the host system
Basic understanding of MQTT protocol concepts and publish/subscribe messaging patterns
Familiarity with SSL certificate management for secure MQTT connections
Network configuration knowledge for firewall rules and load balancer setup
Understanding of IoT device authentication methods and connection security

For development & testing. Review security settings, change default credentials, and test thoroughly before production use. See Terms

docker-compose.yml

1services: 
2  emqx: 
3    image: emqx/emqx:latest
4    container_name: emqx
5    restart: unless-stopped
6    environment: 
7      EMQX_NAME: emqx
8      EMQX_HOST: 127.0.0.1
9    volumes: 
10      - emqx_data:/opt/emqx/data
11      - emqx_log:/opt/emqx/log
12    ports: 
13      - "1883:1883"
14      - "8083:8083"
15      - "8084:8084"
16      - "8883:8883"
17      - "18083:18083"
18
19volumes: 
20  emqx_data: 
21  emqx_log:

.env Template

.env

1# Default dashboard: admin / public

Usage Notes

1Docs: https://www.emqx.io/docs/
2Dashboard at http://localhost:18083, default: admin/public
3MQTT on 1883, MQTT/SSL on 8883, WebSocket on 8083/8084
4Supports millions of concurrent connections
5Built-in rule engine for data processing
6Enterprise features: clustering, bridges, integrations

Quick Start

terminal

1# 1. Create the compose file
2cat > docker-compose.yml << 'EOF'
3services:
4  emqx:
5    image: emqx/emqx:latest
6    container_name: emqx
7    restart: unless-stopped
8    environment:
9      EMQX_NAME: emqx
10      EMQX_HOST: 127.0.0.1
11    volumes:
12      - emqx_data:/opt/emqx/data
13      - emqx_log:/opt/emqx/log
14    ports:
15      - "1883:1883"
16      - "8083:8083"
17      - "8084:8084"
18      - "8883:8883"
19      - "18083:18083"
20
21volumes:
22  emqx_data:
23  emqx_log:
24EOF
25
26# 2. Create the .env file
27cat > .env << 'EOF'
28# Default dashboard: admin / public
29EOF
30
31# 3. Start the services
32docker compose up -d
33
34# 4. View logs
35docker compose logs -f

One-Liner

Run this command to download and set up the recipe in one step:

terminal

1curl -fsSL https://docker.recipes/api/recipes/emqx/run | bash

Troubleshooting

Connection refused on port 1883: Verify the container is running and port mapping is correct with 'docker ps'
Dashboard shows 'admin/public' login failure: Reset credentials using 'docker exec emqx emqx_ctl admins passwd admin newpassword'
High memory usage with many connections: Increase Docker memory limits and tune EMQX connection pool settings
SSL/TLS handshake failures on port 8883: Check certificate validity and ensure proper SSL configuration in EMQX settings
Message delivery delays under load: Adjust EMQX message queue limits and enable message persistence for better throughput
WebSocket connection timeouts: Configure proxy timeout settings and check for network connectivity issues between clients and port 8083/8084

Community Notes

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