I wrote some Node.js code to allow access to Neuron devices over modbus overlay and made it opensource today.
For now there is only support for digital inputs and outputs/relays but I will be expanding the features in the near future.
I also made an example implementation to allow access over MQTT: https://github.com/wesleydv/node-unipi-neuron-mqtt
Please note I'm not a Node.js developer by trade so surely there will be a lot of things that can be improved in the code.
Any feedback is greatly appreciated.