How can I identify already authorized user?

[Skais]

Hi, I want to identiffy already authorized user if the user re-authorize my app. I think user_id fits for purpose, but It lacks explanation. Does fitbit oauth2 guarantee to return same user_id in every authorization? Any other options available for my purpose if it does not?

[AndrewFitbit · Accepted solution]

@Skais user_id will be the same, even if they re-authorize.