how do they differentiate between internal and external application using Oauth2

Question

Suppose I have a Web Service API defined and would like to implement OAuth Server to provide access to third-party mobile application and my own mobile application.

As these two types of application(internal/external) will try to access my API, what are the possible mechanisms that my authentication server differentiate them?

As an Example, Consider a Facebook app and Lyft (External).While login to facebook through Lyft, fb recognizes it as third-party app and ask for permission level but in Facebook(Internal) app they don't ask permission level. How do they do it?

*Please correct me, if I am wrong here.

Answer 1

OAuth 2.0通过以标识符和共享密钥的形式（分别称为client_id和client_secret的形式授予客户端/应用程序自己的客户端凭据集来区分客户端/应用程序。