MQTTool is an MQTT client and test tool designed for iPhone users. MQTT, short for Message Queuing Telemetry Transport, is a machine-to-machine (M2M) messaging protocol commonly used for IoT applications. It enables devices to communicate with each other efficiently and reliably.

With MQTTool, users can connect to both authenticated and unauthenticated MQTT brokers. The tool allows users to subscribe to topics and publish messages to topics, making it a versatile tool for testing MQTT-based applications.

MQTTool was developed by Brent Petit, who built it during his own MQTT investigations. He decided to share it with others, hoping that they would find it useful as well. Brent continues to use the tool on his own projects and is actively seeking feedback to further improve it.

Overall, MQTTool is a valuable resource for anyone working with MQTT and looking for a reliable client and test tool. It offers a user-friendly interface and essential features for MQTT communication.