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)
Donate
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.
Release files for Flask 3.1.3
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| flask-3.1.3.tar.gz | 759.0 kB | Details |
Built distribution (wheel)
| File | Interpreter | ABI | Platform | Reset |
|---|---|---|---|---|
| flask-3.1.3-py3-none-any.whl | Python 3 | none | any | Details |
Total release size: 862.4 kB
Release files / flask-3.1.3.tar.gz
| Download URL | flask-3.1.3.tar.gz |
|---|---|
| Size | 759.0 kB |
| Tags | Source |
|
SHA-256 checksum How to use checksums |
0ef0e52b8a9cd932855379197dd8f94047b359ca0a78695144304cb45f87c9eb
|
|
BLAKE2b-256 checksum How to use checksums |
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|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/6.1.0 CPython/3.13.7
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on Feb 19, 2026.
Transparency logRelease files / flask-3.1.3-py3-none-any.whl
| Download URL | flask-3.1.3-py3-none-any.whl |
|---|---|
| Size | 103.4 kB |
| Tags | Python 3 |
|
SHA-256 checksum How to use checksums |
f4bcbefc124291925f1a26446da31a5178f9483862233b23c0c96a20701f670c
|
|
BLAKE2b-256 checksum How to use checksums |
7f9c34f6962f9b9e9c71f6e5ed806e0d0ff03c9d1b0b2340088a0cf4bce09b18
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/6.1.0 CPython/3.13.7
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on Feb 19, 2026.
Transparency log
