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 project. The development is driven by Cedalo.

Download and Security

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

Read the Change Log to find out about recent releases.

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


You can have your own instance of Mosquitto running in minutes, but to make testing even easier, the Mosquitto Project runs a test server at where you can test your clients in a variety of ways: plain MQTT, MQTT over TLS, MQTT over TLS (with client certificate), MQTT over WebSockets and MQTT over WebSockets with TLS.

Alternatively, Cedalo offers a free 14-day cloud trial or a 30-day on-premises trial with basic HA configuration. Sign up for a trial instance here.



Support is always available from the community channels on a best effort basis. If you require commercial support, Cedalo can offer support for hosted or on-premise instances, consulting on the use of Mosquitto, and custom development to your needs.

Cedalo provides Mosquitto users with tailored professional support. It includes early access to the latest patches & bug fixes. Learn more about the support service here.


Learn more about MQTT with Cedalo’s MQTT Academy. It is completely free, and it is designed for beginners and experienced professionals.

The courses cover everything from the basics of MQTT to more advanced topics like Quality of Service (QoS) levels. Sign up here! Remember to give some feedback.

Related Projects

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

Streamsheets is an easy to use web based real time spreadsheet interface that can be used to process incoming data from a variety of sources, such as MQTT, OPC-UA, and REST. Developers and non-developers can use Streamsheets to control processes and build dashboards, for example. Mosquitto is a core component of Streamsheets.