This is a basic blog application called Flaskr built in the official Flask Tutorial. In this sample Blog Application the users can register, log in and do all the basic tasks related to creating and publishing their own blog posts.
Flask is a web framework, it’s a Python module that lets you develop web applications easily. It’s has a small and easy-to-extend core: it’s a microframework that doesn’t include an ORM (Object Relational Manager) or such features.It does have many cool features like url routing, template engine. It is a WSGI web app framework.