I am writing a back-end in Django for a mobile app I am creating. I need to authenticate a user the first time they open the mobile app through SMS to verify it is a real person
You can use django-passcode as an app in your project. It exposes APIs to "register" a mobile number and "verify" through SMS based passcode. It uses mobile number and device id pair as unique. It also generates and returns a token for future authorization requests from mobile app. You can use Twilio or any other SMS api to send sms.
https://github.com/sgurminder/django-passcode
I appreciate your feedback for django-passcode