Flask provides configuration and conventions, with sensible defaults, to get started. This section of the documentation explains the different parts of the Flask framework and how they can be used, …

Installation Python Version ¶ We recommend using the latest version of Python. Flask supports Python 3.9 and newer. Dependencies ¶ These distributions will be installed automatically when installing …

Flask provides a really simple way to give feedback to a user with the flashing system. The flashing system basically makes it possible to record a message at the end of a request and access it on the …

The tutorial only uses what’s provided by Flask and Python. In another project, you might decide to use Extensions or other libraries to make some tasks simpler. Flask is flexible. It doesn’t require you to …

API ¶ This part of the documentation covers all the interfaces of Flask. For parts where Flask depends on external libraries, we document the most important right here and provide links to the canonical …

from flask import Flask app = Flask(__name__) @app.route('/') def hello(): return 'Hello, World!' However, as a project gets bigger, it becomes overwhelming to keep all the code in one file. Python …

Welcome to Flask's documentation. Flask is a lightweight WSGI web application framework. It is designed to make getting started quick and easy, with the ability to scale up to complex applications. …

Development Server ¶ Flask provides a run command to run the application with a development server. In debug mode, this server provides an interactive debugger and will reload when code is changed.

Traditional Flask views will still be appropriate for most use cases, but Flask’s async support enables writing and using code that wasn’t possible natively before. Background tasks ¶ Async functions will …

Aug 19, 2025 · Flask and Blueprint now provide a get_send_file_max_age hook for subclasses to override behavior of serving static files from Flask when using Flask.send_static_file (used for the …