Do you know the unique user id in multi tenant Azure AD apps pattern?
I'm now developing app using Microsoft Graph with Azure AD multi-tenant application pattern. For identifying each user I want to know the unique id - I'll use it as a key in our own database to save user's data.
In this reference, id parameter in user object is "The unique identifier for the user", but I wonder is it unique id in each tenant or in all tenant? It is important thing because my app will use in multi tenant.
FYI: If user id is unique only in each tenant, I'll concatenate organization id and user id for making unique id in all tenant.