Hi there, subject already explains itself. Any ideas?
It depends on whether the user you want to fetch the follower list on behalf of is also a user of your site. If this is a feature you want to offer to your users, then you probably want to use OAuth 1.0A and ask that they approve your application to act on their behalf. That way when they ask “who follows user XYZ” the rate limits and context is that THEY are asking, through your application.
If your application wants to know this information, but not necessarily on behalf of a specific user, then app only auth might be the better choice for you.