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.

The Eclipse Foundation
Mosquitto is part of the Eclipse Foundation, and is an project.
Cedalo Gmbh
Mosquitto development is driven by Cedalo, who also offer support, premium services and features, such as hosting and high-availability.

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 offer a two week free hosted trial instance.



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

Cedalo provides Mosquitto users with tailored professional support. This includes early access to the latest patches & bug fixes. You can learn more about the support service here.

Cedalo also offer hosted or on-premise instances, consulting on the use of Mosquitto, or custom development to your needs.


MQTT is the most popular communication protocol in the Internet of Things (IoT). It is used for moving data among applications as well as industrial IoT devices, such as sensors, machines, PLCs, and more.

MQTT efficiently connects clients on the edge, in the cloud and in hybrid infrastructures using a publish /subscribe (Pub/Sub) communication pattern and always has a broker (cluster) at its core. If you want to find out more, take this free MQTT introduction course provided by Cedalo. Dig in, have fun and do not forget 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.