Nope. You can use whatever packages you like. Those you've rolled yourself, standard python packages like psycopg2, redis-py etc., Flask community provided pack

Nope. You can use whatever packages you like. Those you've rolled yourself, standard python packages like psycopg2, redis-py etc., Flask community provided packages and anything in between. I'm building a fairly large webapp in Flask and rarely, if at all, use any Flask packages other than the core itself.