Two factor authentication adds an extra layer of security to your Fitbit account.
Source: Fitbit rolling out two-factor authentication (2FA) for accounts - 9to5GoogleFitbit is finally rolling out support for two-factor authentication (2FA). It’s not yet widely available and leverages SMS text messages.
Fitbit users on Android and iOS are beginning to see a “Increase your security” prompt that explains how “two-factor authentication gives you an extra layer of protection.” Fitbit’s 2FA system sees codes sent to your phone via SMS. It’s not the most secure method, given carrier spoofing, but better than nothing at this point.