Flake8 is a popular lint wrapper for python. Under the hood, it runs three other tools and combines their results:

Run Locally

The mozlint integration of flake8 can be run using mach:

$ mach lint --linter flake8 <file paths>

Alternatively, omit the --linter flake8 and run all configured linters, which will include flake8.


Path configuration is defined in the root .flake8 file. Please update this file rather than tools/lint/flake8.yml if you need to exclude a new path. For an overview of the supported configuration, see flake8’s documentation.


The flake8 linter provides a --fix option. It is based on autopep8. Please note that autopep8 does NOT fix all issues reported by flake8.