Howdy all!
After some interest from a few days ago, I’ve started working on a C# library for WaniKani’s Private API; also (perhaps) known as the “Detrimental API”:
https://github.com/ddoodm/WaniKani-Private-API-CSharp
The library provides a means for third party app developers to gather radical / kanji / vocab information, retrieve review / lesson queues, and update lesson / review progress, and hopefully other stuff soon. .NET is super widespread and portable, so you should be able to use this library in your own web apps, mobile apps, desktop software, and Unity games!
It isn’t done yet, by any means, and it’s pretty holy and disjoint right now (partially because the API sends only the data that is crucially needed by the web app, and also because I didn’t spend enough time thinking about design). There are also a good few holes here and there in the way of checking authentication and such, but that’s all easily fixed. Oh, and please excuse the ahem “Unit Test Project” cough cough.
Regardless, it’d be an honor if anyone wanted to help the project along - there’s quite a bit still yet to do!
The project’s repository is here:
https://github.com/ddoodm/WaniKani-Private-API-CSharp
Thanks for taking a look :)
Sounds great! Thank you.
Thanks! 
Hope it’s useful to someone.