The beauty of MQTT is—apart from the things that you already know about—its landscape of servers, libraries, and apps with MQTT support, which you can mix and match in any way that you like.
It has never been this easy to control your Arduino project from your smartphone, without the need to write additional iOS or Android code. For this, you can utilize one of the many iOS and Android apps that connect to your MQTT server of choice, in the same way that Arduino does. It's just another MQTT client.
Apps with MQTT support serve two main purposes:
- Logging/visualization/inspection of your MQTT devices and their data (passive).
- Controlling your MQTT devices and sending commands (active).
While some apps exist that work purely using text (MQTT topic and message), and that are especially useful for debugging, there are a few that...