Question, does this fire on every external login event or only one time only to locate the matching local user account? I'm asking because if I add logic here to set the user's roles, if the external login provider changes the user's claims later, I need that user's assigned roles to be updated.

Hi, yes the OnExternalLogin event fires every time the user logs in.

Ok, what about OnAutoLinking?

OnAutoLinking is called the first time when the user logs in / registers

Thanks