unofficial API Client written in .NET Core for GUS Regon API (https://api.stat.gov.pl/Home/RegonApi)
This project was createed to speed up process of consuption Regon API from GUS Package is listed on NuGet https://www.nuget.org/packages/Gus.Regon.BIR11.Proxy/ so you an easily reference package by installing it in nuget pacakage manager.
Example how to use it you can find under integration test. Remember to request valid user token by sending mail to GUS with proper request form and reference production api endpoint!