Hiding private details from open source projects

Question

I have a .net github project that is basically a wrapper around a web API. In the test project, I am calling to the API using an API key. I need to keep this key private, how do

Answer 1

Perhaps you can store the key outside of the Config.cs file and load it at run time.

Bonus, other people using your code won't have to recompile the project to change to their API key.