opensource MQTT broker
Eclipse Mosquitto is an open source (EPL/EDL licensed) message broker that implements the MQTT protocol (at the time of writing, versions 3.1, 3.1.1, and 5.0). MQTT 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 like the Arduino. 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.
Homepage: https://mosquitto.org/