I am having trouble understanding how a user vs. app-only authentication works. If I have have 16 users, each one gets to make 15 requests per rate window. But if I have an application, and these 16 users are on this app, do they each get another 15 requests per 15 minute window using app only auth.? Or if I try to make request with my app do I only get 15 requests per 15 minutes no matter how many users are on it?
No the app only auth rate limits do not expand or contract based on the number of users you have, it will remain the same.