I'm curious about your comment that Flask is 'great for small and large apps' and your advice 'at this point you might consider... Django'.
From my limited experience of trying to build things with both, my impression is that Django has a steeper learning curve because of the project/app distinction, and urls.py but that, after some time, the additional structure this imposes makes it less likely that my code becomes a mess.
With Flask, it was super-fast to get started, and to add functionality incrementally, but at some point I realised my code was all in one file, which didn't seem right.
If, as you say, Flask is suitable for large projects like GAuthify, how do you structure your code so as to avoid the problem I faced?
Under what circumstances would you use Django for a project instead of Flask?