DZone recently released my refcard „Getting started with MQTT“. I’m very happy with the result and I hope you’ll find it useful.

You can download the refcard here: https://dzone.com/refcardz/getting-started-with-mqtt

The refcard covers the following topics:

• Why MQTT?
• What Is MQTT?
• Publish / Subscribe
• MQTT Message Types
• Topics
• QoS Levels
• Last Will and Testament
• Retained Messages
• Clean / Persistent Sessions
• MQTT Clients
• Trying MQTT on the Command Line: Linux and Mac OS X
• Pub / Sub With Paho
• MQTT Over Websockets
• Scaling MQTT
• MQTT and Security
• New Features in the MQTT 3.1.1 Standard