pallets/flask

The Python micro framework for building web applications.

74,268

stars

4,942

commits

Python

primary language

Sep 8, 2026

updated

flask.palletsprojects.com
flask
jinja
pallets
python
web-framework
werkzeug
wsgi
Browse cluster: Template engines and web frameworks

README

Flask

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. It began as a simple wrapper around Werkzeug and Jinja, and has become one of the most popular Python web application frameworks.

Flask offers suggestions, but doesn't enforce any dependencies or project layout. It is up to the developer to choose the tools and libraries they want to use. There are many extensions provided by the community that make adding new functionality easy.

A Simple Example

# save this as app.py
from flask import Flask

app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello, World!"
$ flask run
  * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

The Pallets organization develops and supports Flask and the libraries it uses. In order to grow the community of contributors and users, and allow the maintainers to devote more time to the projects, please donate today.

Contributing

See our detailed contributing documentation for many ways to contribute, including reporting issues, requesting features, asking or answering questions, and making PRs.

Contributors

(top 30 of 400)

davidism

1,855 commits

mitsuhiko

1,189 commits

untitaker

274 commits

rduplain

122 commits

pallets/flask

The Python micro framework for building web applications.

74,268

stars

4,942

commits

Python

primary language

Sep 8, 2026

updated

flask.palletsprojects.com
flask
jinja
pallets
python
web-framework
werkzeug
wsgi
Browse cluster: Template engines and web frameworks

README

Flask

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. It began as a simple wrapper around Werkzeug and Jinja, and has become one of the most popular Python web application frameworks.

Flask offers suggestions, but doesn't enforce any dependencies or project layout. It is up to the developer to choose the tools and libraries they want to use. There are many extensions provided by the community that make adding new functionality easy.

A Simple Example

# save this as app.py
from flask import Flask

app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello, World!"
$ flask run
  * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

The Pallets organization develops and supports Flask and the libraries it uses. In order to grow the community of contributors and users, and allow the maintainers to devote more time to the projects, please donate today.

Contributing

See our detailed contributing documentation for many ways to contribute, including reporting issues, requesting features, asking or answering questions, and making PRs.

Contributors

(top 30 of 400)

davidism

1,855 commits

mitsuhiko

1,189 commits

untitaker

274 commits

rduplain

122 commits

Languages

Python

99.9%