Here is a C# Dotnet Port of the ETN client API’s (based on the PHP vendor). With a nuget package for simple install. It contains a client library with unit tests, and a web application to test qrcode generation and webhook processing.
You can use visual studio code, visual studio 2017, or just run directly from the command line using dotnet core
It would be great if people can review it, and provide any feedback.
Source is here: