It happens: you start using a module in your project and it works and you don't realise that it's only being included in your virtualenv because it's a dependency of a package you're using. pip-missing-reqs finds those modules so you can include them in the requirements.txt for the project.

Alternatively, you have a long-running project that has some packages in requirements.txt that are no longer actively used in the codebase. The pip-extra-reqs tool will find those modules so you can remove them.

Assuming your project follows a layout like the suggested sample project:

setup.py
setup.cfg
requirements.txt
sample/__init__.py
sample/sample.py
sample/tests/test_sample.py

Basic usage, running in your project directory:

<activate virtualenv for your project>
pip-missing-reqs --ignore-file=sample/tests/* sample

This will find all imports in the code in "sample" and check that the packages those modules belong to are in the requirements.txt file.

Additionally it is possible to check that there are no dependencies in requirements.txt that are then unused in the project:

<activate virtualenv for your project>
pip-extra-reqs --ignore-file=sample/tests/* sample

This would find anything that is listed in requirements.txt but that is not imported by sample.

To make your life easier, copy something like this into your tox.ini:

[testenv:pip-check-reqs]
deps=-rrequirements.txt
commands=
    pip-missing-reqs --ignore-file=sample/tests/* sample
    pip-extra-reqs --ignore-file=sample/tests/* sample

Your test files will sometimes be present in the same directory as your application source ("sample" in the above examples). The requirements for those tests generally should not be in the requirements.txt file, and you don't want this tool to generate false hits for those.

You may exclude those test files from your check using the --ignore-file option (shorthand is -f). Multiple instances of the option are allowed.

If your project has modules which are conditionally imported, or requirements which are conditionally included, you may exclude certain modules from the check by name (or glob pattern) using --ignore-module (shorthand is -m):

# ignore the module spam
pip-missing-reqs --ignore-module=spam sample
# ignore the whole package spam as well
pip-missing-reqs --ignore-module=spam --ignore-module=spam.* sample

If your project uses pyproject.toml, there are multiple ways to use pip-check-reqs with it.

One way is to use an external tool to convert pyproject.toml to requirements.txt:

# requires `pip install pdm`
pdm export --pyproject > requirements.txt

# or, if you prefer uv, `pip install uv`
uv pip compile --no-deps pyproject.toml > requirements.txt

Then you can use pip-missing-reqs and pip-extra-reqs as usual.

Another way is to use a requirements.txt file within your pyproject.toml file, for example with the setuptools build backend:

[build-system]
build-backend = "setuptools.build_meta"
requires = [
  "setuptools",
]

[project]
...
dynamic = ["dependencies"]

[tool.setuptools.dynamic]
dependencies = { file = "requirements.txt" }

Josh Hesketh -- who refactored code and contributed the pip-extra-reqs tool.

Wil Cooley -- who handled the removal of normalize_name and fixed some bugs.