hivemq-community-edition VS MQTTnet

It is developed and supported by HiveMQ, so if you observe any issue you can contact the developers directly.

Kudzai Manditereza is a Developer Advocate at HiveMQ and the Founder of Industry40.tv. He is the host of an IIoT Podcast and is involved in Industry4.0 research and educational efforts.

If you are looking to use a locally-hosted broker deployed on the device, I wanted to recommend the following : HiveMQ supports a community edition broker that is free to use, open-source, and can be configured and deployed locally or on cloud providers, such as AWS, GCP, or Azure.

Were any of them HiveMQ Community Edition by any chance?

MQTT https://github.com/dotnet/MQTTnet

MQTTNet - High perf IOT comms for .NET - https://github.com/dotnet/MQTTnet

I'm trying to use MQTT.Net and so far everything works.. except for event handling.

Like the other guy said it depends on the requirements, but you could implement your own mqtt server with MQTTnet with a few lines of code

For the server we used mosquitto because we already used it in the past (and it's relatively simple), for the client MQTTnet because it's .net and it seemed good enough (mosquitto has a client library too but it's C so I'd have to write some interop). It's a simple protocol so it shouldn't really matter which implementation you use.

We are going to use MQTTNet as the foundation for this article, although the same concepts can be applied with any other MQTT client.

[2] https://github.com/dotnet/MQTTnet

For example, I used MQTTnet which is a very nice (high performance & extensible) library. And it's free/open source. If you're not writing your server code in .NET, then look for whatever broker libraries are available on your server platform.