[RandomThoughts3]

MQTT is pub/sub protocol with a concept of brokers and clients. It's not in anyway comparable to TCP. You could rewrite an equivalent of MQTT on top of TCP in a fairly straightforward way - MQTT is simple by design - but I think you take the question from the wrong end. Why would you write a new protocol when MQTT already exists and does the job?

[rendaw]

The effort to vet MQTT providers, integrate them, and configure everything properly, understand and work around MQTT and implementation quirks, and the protocol overhead were greater than doing something directly on top of TCP, and I don't believe I lost any features that I needed.