pyflakes

passive checker of Python programs

pyflakes Permissive license MIT AGING ★ 1,456 v3.4.0 released 2025-06-20

Install

pyflakes on PyPI

pip

pip install pyflakes

uv

uv add pyflakes

poetry

poetry add pyflakes

Package facts

License	MIT (permissive)
Python support	supports the current Python release (>=3.9)
Install friction	low — pure-Python wheel
Runtime dependencies	none
Maintenance	aging — 419 days since the last release
Last repo commit	2025-06-20
First released	2009-01-30
Popularity	one of the top 1,000 most-downloaded packages on PyPI (30-day window, as of 2026-08-13)
Known vulnerabilities	none known (OSV.dev, checked 2026-08-13)

Evidence: pyflakes-3.4.0-py2.py3-none-any.whl

Development Status :: 6 - MatureEnvironment :: ConsoleIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: Implementation :: CPythonProgramming Language :: Python :: Implementation :: PyPyTopic :: Software DevelopmentTopic :: Utilities

About pyflakes

from the package's own PyPI description — quoted content, verbatim

======== Pyflakes ========

A simple program which checks Python source files for errors.

Pyflakes analyzes programs and detects various errors. It works by parsing the source file, not importing it, so it is safe to use on modules with side effects. It's also much faster.

It is available on PyPI <https://pypi.org/project/pyflakes/>_ and it supports all active versions of Python: 3.9+.

Installation

It can be installed with::

$ pip install --upgrade pyflakes

Useful tips:

Be sure to install it for a version of Python which is compatible with your codebase: python#.# -m pip install pyflakes (for example, python3.10 -m pip install pyflakes)
You can also invoke Pyflakes with python#.# -m pyflakes . if you want to run it for a specific python version.
If you require more options and more flexibility, you could give a look to Flake8_ too.

Design Principles

Pyflakes makes a simple promise: it will never complain about style, and it will try very, very hard to never emit false positives.

Pyflakes is also faster than Pylint_. This is largely because Pyflakes only examines the syntax tree of each...

Read as markdown · JSON record · Source repository · Homepage

AI interpretation — verify before relying

AI-generated interpretation of the package facts above; every digit, version, license, or vulnerability id it cites is grounded in the facts already shown on this page

Pyflakes is a fast, lightweight static checker that detects errors in Python source files by parsing syntax without importing, making it safe for code with side effects.

Installation is straightforward with no runtime dependencies and a pure-Python wheel distribution. The project shows aging maintenance (419 days since last release) but remains actively developed with recent commits and a mature codebase.

MIT license permits unrestricted use, modification, and distribution with minimal restrictions, making it suitable for both open-source and proprietary projects.

Usage

pip install pyflakes
python -m pyflakes your_file.py

Requires Python 3.9 or later; install for the specific Python version you intend to check.

Verdict: Pyflakes is a mature, well-maintained static checker with zero known vulnerabilities, no dependencies, and permissive licensing. Its low install friction and focus on error detection without false positives make it a reliable choice for Python code quality workflows, though its last release was over a year ago.

Needs verification

Whether the 419-day gap since last release reflects intentional stability or reduced maintenance capacity.
Performance characteristics compared to alternatives for large codebases.
Scope of errors detected relative to modern Python language features (3.9+).

python static analysiscode error detectionlinting without importssyntax checker pythonfast python code analysispyflakes alternativepassive python checker