How to get all customers in Magento 2 Using .Net and C#
You need to construct an instance of Magento class with your Magento URL, user name and password.
Example:
var magento = new Magento("http://ypur-magento.com", "username", "password");
var customers = magento .GetAllCustomers();
Simply use an admin account which has required permissions to access web api resource.