MQTT FX is a popular, open-source MQTT client tool used for testing and debugging MQTT-based applications. It provides a graphical user interface (GUI) to interact with MQTT brokers, subscribe to topics, publish messages, and monitor the communication.
As MQTT FX is open-source software, there is no license key required to use it. You can download the software, install it, and use it freely. mqtt fx license key
While there is no commercial support available, MQTT FX has an active community of users and developers who contribute to the project, provide support, and share knowledge. MQTT FX is a popular, open-source MQTT client