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. To evaluate an enterprise-ready MQTT broker, check out HiveMQ MQTT broker.
For a quick introduction to MQTT, check out our MQTT Essentials blog series, our MQTT Glossary Page and MQTT FAQ.
Public MQTT Broker
Our Public HiveMQ MQTT broker is open for anyone to use. Feel free to write an MQTT client that connects with this broker. We have a dashboard so you can see the amount of traffic on this broker. We also keep a list of MQTT client libraries that can be used to connect to HiveMQ.
You can access the broker at:
Broker:
broker.hivemq.com TCP Port:
1883 Websocket Port:
8000 
For an in-depth evaluation of HiveMQ, visit our Get HiveMQ page or get all information about our MQTT broker.