Hi there!
MQTT.fx aims to be an quick and easy to use desktop tool for MQTT debugging and testing.
I am working on MQTT.fx since more than 3 years(mostly at night) in my very, very rare sparetime.
By now MQTT.fx had more than thirty released versions (almost 1 per month) and ciritical bugs are fixed instantly.
Bundled Installers available for Windows, Mac and Linux at: www.mqttfx.org
Twitter: @mqtt_fx