Eclipse Mosquitto is an open source (EPL/EDL licensed) message broker that implements the MQTT protocol versions 5.0, 3.1.1 and 3.1. Mosquitto is lightweight and is suitable for use on all devices from low power single board computers to full servers.

The MQTT protocol provides a lightweight method of carrying out messaging using a publish/subscribe model. This makes it suitable for Internet of Things messaging such as with low power sensors or mobile devices such as phones, embedded computers, or microcontrollers.

The Mosquitto project also provides a C library for implementing MQTT clients, and the very popular mosquitto_pub and mosquitto_sub command line MQTT clients.

Mosquitto is part of the Eclipse Foundation, and is an iot.eclipse.org project, with its development driven by Cedalo.

Download and Security

Mosquitto is highly versatile and available with a wide range of platforms. Go to the dedicated download page to find the source or binaries for your platform.

For details on recent releases, check the Change Log

Use the security page to find out how to report vulnerabilities or responses to past security issues.

Test

Settin up your own Mosquitto instance is quick and straightforward. But, for added convenience the Mosquitto project runs a test MQTT server at test.mosquitto.org, which supports various testing options, such as:

  • Plain MQTT
  • MQTT over TLS
  • MQTT over TLS (with client certificate)
  • MQTT over WebSockets
  • MQTT over WebSockets with TLS

Alternatively, sign up for the Cedalo MQTT Platform trial, which combines the Pro Edition for Mosquitto MQTT broker and the Management Center for Mosquitto web UI, to test advanced MQTT broker features in various scenarios.

Community

You can engage with the Mosquitto community through various channels:

Support

Support is always available from the community channels on a best effort basis.

Cedalo provides comprehensive open-source Mosquitto support:

  • Hosted or on-premises instances
  • Consulting on Mosquitto usage
  • Custom development tailored to your needs

Training

Learn more about MQTT with Cedalo’s MQTT Academy - a completely free resource designed for beginners and experienced professionals.

The courses cover everything from the basics of MQTT to more advanced topics. Sign up and remember to share your feedback!

Related Projects

Several tools and platforms complement Mosquitto, and can enhance its capabilities to accommodate a variety of use cases:

Paho provides MQTT client library implementations in a wide variety of languages.

What is an MQTT broker?

An MQTT message broker is a central component that enables communication between clients and IoT devices using the MQTT protocol. It follows the publish-subscribe (pub/sub) messaging model, which plays a crucial role in managing MQTT connections and performing data transmission. The broker receives messages from publishers, verifies their publishing rights, and queues messages according to their Quality of Service (QoS) levels. It further identifies authorised subscribers and routes them to appropriate subscribers.

As the backbone of the MQTT ecosystem, the broker ensures secure and reliable message delivery across devices, making it essential for efficient IoT communication and data exchange.

Types of MQTT broker

MQTT message broker type comparison:

Type Description
Open-source MQTT broker
  • Often available at minimal or no cost, these brokers offer the flexibility to modify the code to suit your specific requirements.
  • They are typically maintained by open-source communities, and are ideal for testing, prototyping, personal projects and small to medium-scale applications.
  • Examples: Mosquitto
Cloud MQTT broker
  • An online MQTT broker hosted and run by a cloud service provider that manages infrastructure, providing scalability and reducing maintenance efforts.
  • These brokers are ideal for large-scale IoT deployments.
  • Examples: AWS IoT Core and Azure IoT Hub.
On-premises (local, self-hosted) MQTT broker
  • Installed and hosted directly on an individual’s or organisation’s servers/infrastructure for complete control over broker environment, data security, and configuration.
  • Local MQTT broker setups are ideal for organizations that must meet stringent regulatory requirements and maintain full control over their data.
  • Examples: Pro Edition for Mosquitto
Enterprise MQTT broker
  • Commercial-grade MQTT broker that offers rich features and robust support for mission-critical IoT applications.
  • Examples: Pro Edition for Mosquitto

What is an IoT MQTT broker used for?

An MQTT broker is applicable in various use cases across industries such as manufacturing, healthcare, automotive, smart home systems, and more.

  • Using an MQTT broker as a data transmission solution can help manufacturers generate real-time insights into machinery performance to drive smarter operations. By collecting sensor data such as temperature, pressure, and vibration, manufacturers can implement predictive maintenance measures and improve overall efficiency by reducing downtime.
  • It can also be applied to energy management systems to aggregate electricity usage data from smart meters across distributed locations. This allows energy providers to track consumption patterns, identify disruptions, and maintain grid stability. Moreover, performing such monitoring can also help optimize energy distribution and enable rapid response to outages.

How to choose the right MQTT message broker for your needs

Consider the following factors when selecting an MQTT broker for your deployment:

Capability Description
Features To meet the demands of enterprise or mission-critical applications, the broker must offer advanced capabilities like High Availability, enhanced logging and security, integrations with various services and databases, MQTT broker management and monitoring, REST APIs, and more.
Clustering To ensure the continuous operation of your deployment in the event of downtime, the broker must support High Availability clustering.
Scalability With growing system demands, the broker must possess robust scalability features to efficiently manage increasing MQTT message volumes and client connections.
Security To guarantee data security and protection, the broker must offer security mechanisms such as authentication and authorization, client access via credentials, TLS encryption, access control lists (ACLs), and more.
Administration and Monitoring Efficient broker management requires a web UI that enables instance and cluster configuration, user and client management, performance metric monitoring, and provides an overview of the entire setup.

Difference between Open-Source and Enterprise Pro Edition for Mosquitto MQTT Broker

Feature Open-source Mosquitto Pro Mosquitto
License Open source (Free) Commercial license
Deployment options On-premises Cloud or on-premises
Feature set Core MQTT features High Availability, various integrations, REST APIs, persistent queuing, etc.
Support Community-based via forums Dedicated professional support from Cedalo experts

For a complete open-source vs Pro Edition for Mosquitto MQTT broker features list, refer to this PDF comparison.