I've used both Flask and Django more or less extensively: generally I like to start out in Flask and move to Django if necessary, as opposed to the other way around.
The three big things I think Django has over Flask:
- ORM
- Django-admin
- A stronger ecosystem
(But of course, none of these are entirely absent from Flask -- its not as if its particularly difficult to plug in SQLAlchemy, and I believe there's a Flask-admin package nowadays.)
My general advice is that if you feel like the thing you're developing is going to turn into a CRUD app, use Django.
The three big things I think Django has over Flask:
- ORM
- Django-admin
- A stronger ecosystem
(But of course, none of these are entirely absent from Flask -- its not as if its particularly difficult to plug in SQLAlchemy, and I believe there's a Flask-admin package nowadays.)
My general advice is that if you feel like the thing you're developing is going to turn into a CRUD app, use Django.