I believe you cannot add restrictions on top of the GPL, which is one of the reasons OpenSSL is not compatible with the GPL for instance. As such, if you licen

I believe you cannot add restrictions on top of the GPL, which is one of the reasons OpenSSL is not compatible with the GPL for instance. As such, if you license your code under the GPL anybody at paypal can use and modify it under the terms of the GPL, as per the terms of the license. What you can do is have a dual license "as long as the combination of restrictions on the work as a whole does not put any additional restrictions beyond what GPL allows"[1]. That being said, I'm not a lawyer, so I might have misinterpreted the wording of the license. [1] https://en.wikipedia.org/wiki/GNU_General_Public_License#Compatibility_and_multi-licensing https://en.wikipedia.org/wiki/GNU_General_Public_License#Com...