Teslemetry provides access to the Tesla Fleet API and Tesla Fleet Telemetry for the products connected to the Tesla account you use to login. This means Teslemetry does not require a separate username, password, or two factor authentication, and we do not store any of this information either. You can read more about Teslemetry's secure design.
You login to both Teslemetry, and authorise your Tesla account by visiting teslemetry.com/login. This will redirect you to auth.tesla.com where you can enter your Tesla username, password, and two factor authentication (if enabled). If this is your first time logging in, you will be need to choose which scopes (permissions) you want to provide Teslemetry.
The first time you login to Teslemetry, Tesla will prompt you to pick what scopes (permissions) you would like to provide. It is recommended that you enable all scopes to get the most out of Teslemetry, however you can pick and choose any that you want, and change them any time at auth.tesla.com.
You can read more about the Tesla Fleet Telemetry scopes at developer.tesla.com.