Is Flask loaded just once on the server or every time someone visits site?
Flask and all of your dependencies are loaded once when you start your web server, so no need to worry about startup time.
I am just about ready to deploy my Flask based website but before I do, I would like to know if the Flask framework is loaded for each session or if it is loaded just once on the server.  The reason I ask is because I have a lot of python libraries to load and I want to know if I should load them all at once (if Flask is only loaded once) or load them on a page by page basis (if Flask is loaded for each session).  It is really a question about getting the best performance for the end user.