Welcome to Flask — Flask Documentation (3.1.x)
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, customized, and extended.
Installation — Flask Documentation (3.1.x)
Flask is now installed. Check out the Quickstart or go to the Documentation Overview.
Quickstart — Flask Documentation (3.1.x) - Read the Docs
Modern web applications use meaningful URLs to help users. Users are more likely to like a page and come back if the page uses a meaningful URL they can remember and use to directly visit a page. Use the route() decorator to bind a function to a URL.
Tutorial — Flask Documentation (3.1.x) - Read the Docs
Check out the Quickstart for an overview of what Flask can do, then dive into the docs to find out more. 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.
Project Layout — Flask Documentation (3.1.x)
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.
Single-Page Applications — Flask Documentation (3.1.x)
Flask can be used to serve Single-Page Applications (SPA) by placing static files produced by your frontend framework in a subfolder inside of your project. You will also need to create a catch-all endpoint that routes all requests to your SPA. The following example demonstrates how to serve an SPA along with an API:
SQLAlchemy in Flask — Flask Documentation (3.1.x)
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. This is recommended if you want to get started quickly.
Application Structure and Lifecycle — Flask Documentation (3.1.x)
Flask makes it pretty easy to write a web application. But there are quite a few different parts to an application and to each request it handles. Knowing what happens during application setup, serving, and handling requests will help you know what’s possible in Flask and how to structure your application.
Extensions — Flask Documentation (3.1.x)
Extensions are extra packages that add functionality to a Flask application. For example, an extension might add support for sending email or connecting to a database. Some extensions add entire new frameworks to help build certain types of applications, like a REST API.
Testing Flask Applications — Flask Documentation (3.1.x)
Testing Flask Applications¶ Flask provides utilities for testing an application. This documentation goes over techniques for working with different parts of the application in tests. We will use the pytest framework to set up and run our tests.