I am working on a lot of devices lately that use MQTT. I have decided to host my own MQTT broker to make the testing.
If you are testing any MQTT project and you can benefit from this broker feel free to use it. It has basic features for now and I am trying to develop new features whenever I can dedicate time for it.
Host: mqtt.lazyengineers.com
Websocket Port: 10452
TCP Port: 1883
Username: lazyengineers
Password: lazyengineers
I also made a simple javacript client based on Paho. It is still in basic feature beta. At this moment I am working on adding a feature for managing the subscriptions (subscribe/unsubscribe) in an easier way.
I think it is self explanatory
http://www.lazyengineers.com/mqtt-websocket/Everything is open source and you check or participate in the development if you feel like it.
N.B: I am not a software developer, so the code is not in the best shape but it will do.
Peace