RainMaker uses User Name and Password for Authentication mechanism. Internally the User credentials are stored in AWS Cognito. The users here are end users who will be controlling the devices through PhoneAPP or Admin user who is configuring the RainMaker for his/her end users.

User onboarding can be done by Sign Up API

The Login API can be used to get authenticated.

Take a look at RainMaker has User Management APIs.