@jesking Heroku is simpler and more expensive, it is built on top of AWS.
AWS is doable and will simply be more time consuming up front.
IMO, do AWS and simply use the console to set up your application and do a lot of googling.
@adrigo so you authenticate with OAUTH, store their refresh token locally in your database and encrypt it.
You decrypt the refresh token whenever you need to make external calls on their behalf and you request an access token with the Refresh token and these typically last anywhere from 15...