How to Install `flake8` in Python

v7.3.0 CLI & Utilities Python >=3.9 MIT

the modular source code checker: pep8 pyflakes and co

Install pip install flake8

What is flake8?

the modular source code checker: pep8 pyflakes and co

- PyFlakes - pycodestyle - Ned Batchelder's McCabe script

Flake8 runs all the tools by launching the single `` command. It displays the warnings in a per-file, merged output.

- files that contain this line are skipped::

Documentation → PyPI page → Author: Tarek Ziade

Quick Start

Minimal example to get started with flake8:

import flake8

print(flake8.__version__)

Installation

pip (standard)

pip install flake8

Virtual environment (recommended)

python -m venv venv
source venv/bin/activate   # Windows: venv\Scripts\activate
pip install flake8

pip3

pip3 install flake8

conda

conda install -c conda-forge flake8

Poetry

poetry add flake8

Dependencies

Installing flake8 will also install these packages:

mccabe pycodestyle pyflakes

Verify the Installation

After installing, confirm the package is available:

python -c "import flake8; print(flake8.__version__)"

If this prints a version number, installation succeeded. If you see a ModuleNotFoundError, see the errors section below.

Installation Errors

Common errors when installing flake8 with pip.

ModuleNotFoundError: No module named 'flake8'

Cause: The package is not installed in the current Python environment.

Fix: Run pip install flake8. If using a virtual environment, ensure it is activated first.

ModuleNotFoundError: No module named 'flake8' (installed but still failing)

Cause: pip installed the package into a different Python than the one running your script.

Fix: Use python -m pip install flake8 to install into the interpreter you are running.

ImportError: cannot import name 'X' from 'flake8'

Cause: The function or class does not exist in the installed version.

Fix: Check the version with pip show flake8 and upgrade with pip install --upgrade flake8.

pip: command not found

Cause: pip is not in PATH or Python was not added to PATH during installation.

Fix: Try python -m pip install flake8. On macOS/Linux try pip3.

PermissionError: [Errno 13] Permission denied

Cause: No write access to the system Python package directory.

Fix: Use a virtual environment, or add --user: pip install --user flake8

SSL: CERTIFICATE_VERIFY_FAILED

Cause: pip cannot verify PyPI's SSL certificate — common behind corporate proxies.

Fix: Try: pip install --trusted-host pypi.org --trusted-host files.pythonhosted.org flake8

Recent Releases

Version	Released
`7.3.0` latest	2025-06-20
`7.2.0`	2025-03-29
`7.1.2`	2025-02-16
`7.1.1`	2024-08-04
`7.1.0`	2024-06-15

Full release history on PyPI →

Manage flake8

Upgrade to latest version

pip install --upgrade flake8

Install a specific version

pip install flake8==7.3.0

Uninstall

pip uninstall flake8

Check what is installed

pip show flake8

Last updated: 2026-04-11 • Data from PyPI

How to Install flake8 in Python