This section of the documentation explains the different parts of the Flask framework and how they can be used, customized, and extended. Beyond Flask itself, look for community-maintained extensions …

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 …

Flask is now installed. Check out the Quickstart or go to the Documentation Overview.

While it’s designed to give a good starting point, the tutorial doesn’t cover all of Flask’s features. Check out the Quickstart for an overview of what Flask can do, then dive into the docs to find out more.

Then follow the installation instructions to set up a Python virtual environment and install Flask for your project. The tutorial will assume you’re working from the flask-tutorial directory from now on.

Set this to True to enable the test mode of Flask extensions (and in the future probably also Flask itself). For example this might activate test helpers that have an additional runtime cost which should not be …

Flask, as a WSGI application, uses one worker to handle one request/response cycle. When a request comes in to an async view, Flask will start an event loop in a thread, run the view function there, then …

Initialize the Database File ¶ Now that init-db has been registered with the app, it can be called using the flask command, similar to the run command from the previous page.

Because SQLAlchemy is a common database abstraction layer and object relational mapper that requires a little bit of configuration effort, there is a Flask extension that handles that for you.

There’s a lot more to Flask than what you’ve seen so far. Even so, you’re now equipped to start developing your own web applications. Check out the Quickstart for an overview of what Flask can …