erl.mqtt.server MQTT server is designed for communication in Machine to Machine (M2M) and Internet of Things (IoT) contexts and implements MQTT protocol versions 3.1 and 3.1.1. The server is written in Erlang as OTP application. Eurotech Everywhere Cloud Eurotech Everywhere Device Cloud is a cloud-based service provided by Eurotech . FlashMQ. Web. Web. The Free Public MQTT Broker. An MQTT broker, which is the heart of the MQTT Publish/Subscribe protocol, is a server that receives all messages from the MQTT clients and then routes the messages to the appropriate subscribing clients. We host a free online public MQTT broker and HiveMQ MQTT WebSocket client to make it easy for you to experiment with MQTT messages.. It is easy to open the file in any text editor and make a deeper analysis of the messages, which is often necessary when dealing with many MQTT messages. Tools to simulate an MQTT client Now that you have the tools needed it to simulate an MQTT client, you can test with the Ubidots' MQTT broker.