A curated list of awesome flake8 extensions.

Inspired after reading a post.

• All-in-one
• Bugs
• Clean code
• Limitations
• Naming
• Complexity
• Comments
• Docstrings
• Tools
• Imports
• Testing
• Type annotations
• Library-specific checks
• Integrations
• Wrappers
• Formatters

Extensions with more than 20 rules inside.

• dlint - Tool for encouraging best coding practices and helping ensure Python code is secure.
• flake8-bugbear - Finding likely bugs and design problems in your program.
• flake8-pie - Extension that implements misc. lints.
• flake8-simplify - Plugin that helps you to simplify code.
• hacking - Set of flake8 plugins that test and enforce the OpenStack StyleGuide.
• wemake-python-styleguide - The strictest and most opinionated python linter ever.

Extensions for finding possible bugs.

• flake8-2020 - Plugin which checks for misuse of sys.version or sys.version_info.
• flake8-alfred - Alfred is a flake8 plugin to warn on unsafe/obsolete symbols.
• flake8-async - A flake8 plugin that checks for bad async / asyncio practices.
• flake8-dunder-all - Ensures that modules have defined __all__.
• flake8-encodings - Identify incorrect use of encodings.
• flake8-mutable - Detect usage of mutable objects as default values for arguments.
• flake8-qt-tr - Detect incorrectly wrapped Qt translation text.
• flake8-requirements - Package requirements checker.
• flake8-secure-coding-standard - Enforce some secure coding standards for Python.
• flake8-slots - Require __slots__ to be defined for subclasses of immutable types.
• flake8-strftime - Checks for use of platform-specific strftime codes.
• flake8-string-format - Check that indexed parameters are used in strings.
• flake8-unused-arguments - Warn against unused arguments in functions.
• flake8-useless-assert - Detect useless assert statements.
• flake8-warnings - Detect usage of deprecated modules, classes, and functions.

Extensions for finding stylistic issues and enforcing consistent codestyle.

• flake8-all-not-strings - Checks that if modules under __all__ are defined as strings.
• flake8-class-attributes-order - Checks classes attributes order.
• flake8-clean-block - Plugin to enforce a blank line after if/for/while/with/try blocks.
• flake8-commas - Enforcing trailing commas in python.
• flake8-comprehensions - Helps you write better list/set/dict comprehensions.
• flake8-datetime-utcnow-plugin - Plugin to warn the developer of the usage of datetime.utcnow().
• flake8-datetimez - A plugin for flake8 to ban the usage of unsafe naive datetime class.
• flake8-implicit-str-concat - Plugin to encourage correct string literal concatenation.
• flake8-indent-in-def - Plugin to enforce 8-space indentation in function and class definitions.
• flake8-literal - Enforces consistent styling of string literals.
• flake8-multiline-containers - Plugin to ensure a consistent format for multiline containers.
• flake8-newspaper-style - Ensures the function definition goes below its usage.
• flake8-obey-import-goat - Allows to forbid specific imports.
• flake8-picky-parentheses - Checks for redundant parentheses and alignment of parentheses and brackets.
• flake8-quotes - Extension for checking quotes in python.
• flake8-return - Plugin that checks return values.
• flake8-scream - Rules which do have known false-positives but might still be useful for a one-time run.
• flake8-sql - Plugin that checks SQL code against opinionated style rules.
• flake8-strict - Checks Python code against a set of opinionated style rules.
• flake8-too-many - Plugin that prevents you from writing "too many" bad codes.
• tryceratops - Prevent exception handling antipatterns.

Extensions banning specific Python features.

• flake8-broken-line - Report line break with backslash (\).
• flake8-debugger - Report debug statements (pdb, ipdb).
• flake8-forbidden-func - Forbid some functions in some modules.
• flake8-logging - Reports issues in using the standard library logging module.
• flake8-logging-format - Report string formatting inside logging.
• flake8-match - Report match statement.
• flake8-no-implicit-concat - Report implicit string concatenation.
• flake8-no-pep420 - Report implicit namespace packages.
• flake8-pep3101 - Report %-formatting.
• flake8-print - Report print statement.
• flake8-printf-formatting - Report %-formatting.
• flake8-use-fstring - Report %-formatting and str.format.
• flake8-use-pathlib - Report os.path.
• flake8-walrus - Report walrus operator (:=).

Extensions for checking names of variables, functions, etc.

• flake8-builtins - Check for python builtins being used as variables or parameters.
• flake8-functions-names - Validate functions names, decomposition and conformity with annotations.
• flake8-test-name - Checks that test functions names follow a given convention.
• flake8-variables-names - Extension that helps to make more readable variables names.
• pep8-naming - Check the PEP-8 naming conventions.

Extensions for ensuring low code complexity.

• cohesion - Extension for measuring Python class cohesion.
• flake8-annotations-complexity - Plugin to validate annotations complexity.
• flake8-cognitive-complexity - Extension for flake8 that validates cognitive functions complexity.
• flake8-expression-complexity - Plugin to validate expressions complexity.
• flake8-functions - Plugin for validation of function parameters (length, complexity, etc).
• flake8-length - Smart line length validation.

Extensions for checking comments.

• flake8-ado - Check that all Azure DevOps IDs mentioned in the comments are in the correct format and have the corresponding ADO item.
• flake8-author - Checks Python modules for __author__ attributes.
• flake8-coding - Adds coding magic comment checks (coding:) to flake8.
• flake8-comments - Reports redundant comments.
• flake8-copyright - Adds copyright checks to flake8.
• flake8-eradicate - Plugin to find commented out or dead code.
• flake8-executable - Plugin for checking executable permissions and shebangs.
• flake8-fixme - Check for FIXME, TODO and other temporary developer notes.
• flake8-jira-todo-checker - Check that every TODO comment has a valid JIRA issue ID next to it.
• flake8-noqa - Validate # noqa comments.
• flake8-ownership - Checker for assuring that author, copyright, and license are specified in source files.
• flake8-todo - Check for TODO notes.
• flake8-todos - Lint TODO comments to be consistent and have an issue linked.

Extensions for checking docstrings.

• flake8-docstring-checker - Checks if everything has a docstring.
• flake8-docstrings - Include checks provided by pep257.
• flake8-docstrings-complete - Linter that checks docstrings of functions, methods and classes.
• flake8-rst-docstrings - Validate Python docstrings as reStructuredText (RST).
• flake8-spellcheck - Spellcheck variables, classnames, comments, docstrings etc.
• flake8-sphinx-links - Check docstrings for double backticked strings which should be links to the Python documentation.
• pydoclint - A Python docstring linter that checks arguments, returns, yields, and raises sections.

Tools empowering flake8.

• flake8-codes - CLI tool to introspect flake8 plugins and their codes.
• flake8-pyproject - Flake8 plug-in loading the configuration from pyproject.toml.
• flake8-pyprojecttoml - Adds support for reading flake8 config from pyproject.toml.
• flake8-ruler - More powerful configs for flake8.
• flakehell - Wrapper to make it nice, legacy-friendly, and configurable.
• flakes - Web list of flake8 plugins and their codes, a wrapper around flake8-codes.
• nitpick - Enforce the same lint configuration (flake8, isort, mypy, pylint) across multiple Python projects.
• wps-playground - Online playground for wemake-python-styleguide.
• yesqa - A tool to automatically remove unnecessary # noqa comments.
• flake8-in-file-ignores - Allow in file ignore e.g. # flake8-in-file-ignores: noqa: E731.

Extensions for checking import statements.

• flake8-absolute-import - Plugin to require absolute imports.
• flake8-alphabetize - Checking the order of import statements and the __all__ list.
• flake8-datetime-import - Enforce importing datetime as dt and time as tm.
• flake8-future-import - Extension to check imports.
• flake8-import-conventions - How certain packages should be imported or aliased.
• flake8-import-order-spoqa - Spoqa's import order style for flake8-import-order.
• flake8-import-order - Include checks import order against various Python Style Guides.
• flake8-import-style - Plugin to ensure explicit module imports.
• flake8-internal-name-import - Plugin that reports imports of protected names.
• flake8-tidy-imports - Extension that helps you write tidier imports.
• flake8-type-checking - Plugin lets you know which imports to move in or out of type-checking blocks.

Extensions for testing.

• flake8-aaa - Lints tests against the Arrange Act Assert pattern.
• flake8-assertive - Unittest assert method checker.
• flake8-mock - Provides checking mock non-existent methods.
• flake8-mock-spec - Enforce the use of the spec argument on mocks ensuring that your use of mocks is compliant with the interface of the object being mocked.
• flake8-pytest-style - Checks for common style issues or inconsistencies with pytest-based tests.
• flake8-pytest - Enforces to use pytest-style assertions.
• flake8-pytestrail - Checks TestRail test case IDs.

Extensions for type annotations.

• flake8-annotations-coverage - Plugin to validate annotations coverage.
• flake8-annotations - Plugin for flake8 to check for presence of type annotations in function definitions.
• flake8-future-annotations - Verifies Python 3.7+ files use from __future__ import annotations.
• flake8-new-union-types - Plugin to enforce new Union/Optional syntax Foo | Bar | None defined in PEP 604.
• flake8-pep585 - Enforce new style annotations from PEP585 such as list[int] instead of typing.List[int].
• flake8-pep604 - Forbids use of typing.Union (in favour of |), per PEP 604.
• flake8-typing-imports - Plugin which checks that typing imports are properly guarded.

Extensions for linting usage of specific libraries.

• flake8-django-migrations - Plugin to lint for backwards incompatible database migrations in Django.
• flake8-django - Plugin for Django projects.
• flake8-fastapi - Checks FastAPI code against opinionated style rules.
• flake8-numba - Plugin that facilitates code development with numba package.
• flake8-scrapy - Plugin to catch common issues on Scrapy spiders.
• pandas-vet - Plugin that provides opinionated linting for pandas code.
• TorchFix - Plugin for code that uses PyTorch.

Extensions for running flake8 not only on Python files.

• flake8-markdown - Lints Python code blocks in Markdown files using flake8.
• flake8-nb - Runs flake8 on *.ipynb (jupyter notebook) files.
• flake8-pyi - Plugin for Flake8 that provides specializations for type hinting stub files.
• flake8-rst - Checks on code in *.rst files or in docstrings.
• jupyterlab-flake8 - Jupyterlab python linter for notebooks and text files using flake8.

Wrappers around other tools making it possible to use them with flake8.

• flake8-bandit - Wrapper around bandit.
• flake8-black - Wrapper around black.
• flake8-isort - Wrapper around isort.
• flake8-pylint - Wrapper around pylint.

Extensions for formatting flake8 output.

• flake8-dashboard - Generates an HTML dashboard.
• flake8-for-pycharm - Generates pylint-style JSON output.
• flake8-github - Generates GitHub annotation for PR's.
• flake8-gl-codeclimate - Generates GitLab Code Quality artifacts.
• flake8-html - Generates an HTML report.
• flake8-json - Generates JSON output.