Flask is micro WEB framework written in Python. Although by default it's stripped down and doesn't offer much, it's extremly powerfull and extensible. With existing extensions it can be configured as a full blown WEB framework, or you can leave it as small as posible, serving as a micro service - it's up to you.
As Python itself is one of the easiest programming languages to learn, Flask is one of the easiest WEB frameworks to start with, but doesn't limit you with when complex applications are required. Come and learn it with us, give us comments or compare it with your favourite WEB framework.