Flask-Session is a Flask extension that adds server-side session functionality to our application. In Flask Python, a session is a feature that allows you to remember information from one request to the next. A signed cookie is used in a flask program so that the user can inspect and edit the contents of the session. The user can additionally change the sessions if and only if it has the secret key named Flask.secret_key. Flask is a tiny Python framework that works similarly to the MVC framework. As a result, MVC is the ideal choice for Flask.