Contributions are welcome, and they are greatly appreciated! Every little bit helps, and credit will always be given.

Types of Contributions

You can contribute in many ways:

Report Bugs

Report bugs at

If you are reporting a bug, please include:

  • Your operating system name and version.

  • Any details about your local setup that might be helpful in troubleshooting.

  • If you can, provide detailed steps to reproduce the bug.

  • If you don’t have steps to reproduce the bug, just note your observations in as much detail as you can. Questions to start a discussion about the issue are welcome.

Fix Bugs

Look through the GitHub issues for bugs. Anything tagged with “bug” is open to whoever wants to implement it.

Implement Features

Look through the GitHub issues for features. Anything tagged with “enhancement” and “please-help” is open to whoever wants to implement it.

Please do not combine multiple feature enhancements into a single pull request.

Note: this project is very conservative, so new features that aren’t tagged with “please-help” might not get into core. We’re trying to keep the code base small, extensible, and streamlined. Whenever possible, it’s best to try and implement feature ideas as separate projects outside of the core codebase.

Write Documentation

Cookiecutter could always use more documentation, whether as part of the official Cookiecutter docs, in docstrings, or even on the web in blog posts, articles, and such.

If you want to review your changes on the documentation locally, you can do:

pip install -r docs/requirements.txt
make servedocs

This will compile the documentation, open it in your browser and start watching the files for changes, recompiling as you save.

Submit Feedback

The best way to send feedback is to file an issue at

If you are proposing a feature:

  • Explain in detail how it would work.

  • Keep the scope as narrow as possible, to make it easier to implement.

  • Remember that this is a volunteer-driven project, and that contributions are welcome :)

Setting Up the Code for Local Development

Here’s how to set up cookiecutter for local development.

  1. Fork the cookiecutter repo on GitHub.

  2. Clone your fork locally:

    git clone
  3. Install your local copy into a virtualenv. Assuming you have virtualenvwrapper installed, this is how you set up your fork for local development:

    cd cookiecutter/
    pip install -e .
  4. Create a branch for local development:

    git checkout -b name-of-your-bugfix-or-feature

Now you can make your changes locally.

  1. When you’re done making changes, check that your changes pass the tests and lint check:

    pip install tox
  2. Ensure that your feature or commit is fully covered by tests. Check report after regular tox run. You can also run coverage only report and get html report with statement by statement highlighting:

    make coverage

    You report will be placed to htmlcov directory. Please do not include this directory to your commits. By default this directory in our .gitignore file.

  3. Commit your changes and push your branch to GitHub:

    git add .
    git commit -m "Your detailed description of your changes."
    git push origin name-of-your-bugfix-or-feature
  4. Submit a pull request through the GitHub website.

Contributor Guidelines

Pull Request Guidelines

Before you submit a pull request, check that it meets these guidelines:

  1. The pull request should include tests.

  2. The pull request should be contained: if it’s too big consider splitting it into smaller pull requests.

  3. If the pull request adds functionality, the docs should be updated. Put your new functionality into a function with a docstring, and add the feature to the list in

  4. The pull request must pass all CI/CD jobs before being ready for review.

  5. If one CI/CD job is failing for unrelated reasons you may want to create another PR to fix that first.

Coding Standards

  • PEP8

  • Functions over classes except in tests

  • Quotes via

    • Use double quotes around strings that are used for interpolation or that are natural language messages

    • Use single quotes for small symbol-like strings (but break the rules if the strings contain quotes)

    • Use triple double quotes for docstrings and raw string literals for regular expressions even if they aren’t needed.

    • Example:

          'English': "There are %(number_of_lights)s lights.",
          'Pirate':  "Arr! Thar be %(number_of_lights)s lights."
      def lights_message(language, number_of_lights):
          """Return a language-appropriate string reporting the light count."""
          return LIGHT_MESSAGES[language] % locals()
      def is_pirate(message):
          """Return True if the given message sounds piratical."""
          return"(?i)(arr|avast|yohoho)!", message) is not None

Testing with tox

tox uses pytest under the hood, hence it supports the same syntax for selecting tests.

For further information please consult the pytest usage docs.

To run a particular test class with tox:

tox -e py310 -- '-k TestFindHooks'

To run some tests with names matching a string expression:

tox -e py310 -- '-k generate'

Will run all tests matching “generate”, test_generate_files for example.

To run just one method:

tox -e py310 -- '-k "TestFindHooks and test_find_hook"'

To run all tests using various versions of Python, just run tox:


This configuration file setup the pytest-cov plugin and it is an additional dependency. It generate a coverage report after the tests.

It is possible to test with specific versions of Python. To do this, the command is:

tox -e py37,py38

This will run py.test with the python3.7 and python3.8 interpreters.

Core Committer Guide

Vision and Scope

Core committers, use this section to:

  • Guide your instinct and decisions as a core committer

  • Limit the codebase from growing infinitely

Command-Line Accessible

  • Provides a command-line utility that creates projects from cookiecutters

  • Extremely easy to use without having to think too hard

  • Flexible for more complex use via optional arguments

API Accessible

  • Entirely function-based and stateless (Class-free by intentional design)

  • Usable in pieces for developers of template generation tools

Being Jinja2-specific

  • Sets a standard baseline for project template creators, facilitating reuse

  • Minimizes the learning curve for those who already use Flask or Django

  • Minimizes scope of Cookiecutter codebase


Being extendable by people with different ideas for Jinja2-based project template tools.

  • Entirely function-based

  • Aim for statelessness

  • Lets anyone write more opinionated tools

Freedom for Cookiecutter users to build and extend.

  • No officially-maintained cookiecutter templates, only ones by individuals

  • Commercial project-friendly licensing, allowing for private cookiecutters and private Cookiecutter-based tools

Fast and Focused

Cookiecutter is designed to do one thing, and do that one thing very well.

  • Cover the use cases that the core committers need, and as little as possible beyond that :)

  • Generates project templates from the command-line or API, nothing more

  • Minimize internal line of code (LOC) count

  • Ultra-fast project generation for high performance downstream tools


  • Cross-platform and cross-version support are more important than features/functionality

  • Fixing Windows bugs even if it’s a pain, to allow for use by more beginner coders


  • Aim for 100% test coverage and covering corner cases

  • No pull requests will be accepted that drop test coverage on any platform, including Windows

  • Conservative decisions patterned after CPython’s conservative decisions with stability in mind

  • Stable APIs that tool builders can rely on

  • New features require a +1 from 3 core committers

VCS-Hosted Templates

Cookiecutter project templates are intentionally hosted VCS repos as-is.

  • They are easily forkable

  • It’s easy for users to browse forks and files

  • They are searchable via standard Github/Bitbucket/other search interface

  • Minimizes the need for packaging-related cruft files

  • Easy to create a public project template and host it for free

  • Easy to collaborate

Process: Pull Requests

If a pull request is untriaged:

  • Look at the roadmap

  • Set it for the milestone where it makes the most sense

  • Add it to the roadmap

How to prioritize pull requests, from most to least important:

  • Fixes for broken tests. Broken means broken on any supported platform or Python version.

  • Extra tests to cover corner cases.

  • Minor edits to docs.

  • Bug fixes.

  • Major edits to docs.

  • Features.

Pull Requests Review Guidelines

  • Think carefully about the long-term implications of the change. How will it affect existing projects that are dependent on this? If this is complicated, do we really want to maintain it forever?

  • Take the time to get things right, PRs almost always require additional improvements to meet the bar for quality. Be very strict about quality.

  • When you merge a pull request take care of closing/updating every related issue explaining how they were affected by those changes. Also, remember to add the author to

Process: Issues

If an issue is a bug that needs an urgent fix, mark it for the next patch release. Then either fix it or mark as please-help.

For other issues: encourage friendly discussion, moderate debate, offer your thoughts.

New features require a +1 from 2 other core committers (besides yourself).

Process: Roadmap

The roadmap located here

Due dates are flexible. Core committers can change them as needed. Note that GitHub sort on them is buggy.

How to number milestones:

Milestone size:

  • If a milestone contains too much, move some to the next milestone.

  • Err on the side of more frequent patch releases.

Process: Your own code changes

All code changes, regardless of who does them, need to be reviewed and merged by someone else. This rule applies to all the core committers.


  • Minor corrections and fixes to pull requests submitted by others.

  • While making a formal release, the release manager can make necessary, appropriate changes.

  • Small documentation changes that reinforce existing subject matter. Most commonly being, but not limited to spelling and grammar corrections.


  • Ensure cross-platform compatibility for every change that’s accepted. Windows, macOS and Linux.

  • Create issues for any major changes and enhancements that you wish to make. Discuss things transparently and get community feedback.

  • Don’t add any classes to the codebase unless absolutely needed. Err on the side of using functions.

  • Keep feature versions as small as possible, preferably one new feature per version.

  • Be welcoming to newcomers and encourage diverse new contributors from all backgrounds. Look at Code of Conduct.

Becoming a Core Committer

Contributors may be given core commit privileges. Preference will be given to those with:

  1. Past contributions to Cookiecutter and other open-source projects. Contributions to Cookiecutter include both code (both accepted and pending) and friendly participation in the issue tracker. Quantity and quality are considered.

  2. A coding style that the other core committers find simple, minimal, and clean.

  3. Access to resources for cross-platform development and testing.

  4. Time to devote to the project regularly.