Get first day of user's fitbit activity

[sunsri]

Once a user authorizes my app, I would like to get their previous data along with the data generated after approval. I would like to get this all at once (rate limit permitting) so how can I obtain the date that they started using a Fitbit device?

[JeremiahFitbit · Accepted solution]

You can find a person's Fitbit account creation date in the Get Profile endpoint with the memberSince property.

Keep in mind that some people manually import data that predates their account creation.