Contributing Guidelines

Questions, Feature Requests, Bug Reports, and Feedback…

…should all be reported on the Github Issue Tracker .

Ways to Contribute

  • Comment on some of marshmallow’s open issues (especially those labeled “feedback welcome”). Share a solution or workaround. Make a suggestion for how a feature can be made better. Opinions are welcome!
  • Improve the docs. For simple edits, click the ReadTheDocs menu button in the bottom-right corner of the page and click “Edit”. See the Documentation section of this page if you want to build the docs locally.
  • If you think you’ve found a bug, open an issue.
  • Contribute an example usage of marshmallow.
  • Send a PR for an open issue (especially one labeled “please help”). The next section details how to contribute code.

Contributing Code

In General

  • PEP 8, when sensible.
  • Test ruthlessly. Write docs for new features.
  • Even more important than Test-Driven Development–Human-Driven Development.

In Particular

Setting Up for Local Development

  1. Fork marshmallow on Github.

    $ git clone
    $ cd marshmallow
  2. Install development requirements. It is highly recommended that you use a virtualenv.

    # After activating your virtualenv
    $ pip install -r dev-requirements.txt
  3. Install marshmallow in develop mode.

    $ pip install -e .

Git Branch Structure

Marshmallow abides by the following branching model:

Current development branch. New features should branch off here.
Current production release on PyPI.
Maintenance branch for release X.Y. Bug fixes should be sent to the most recent release branch. The maintainer will forward-port the fix to dev. Note: exceptions may be made for bug fixes that introduce large code changes.

Always make a new branch for your work, no matter how small. Also, do not put unrelated changes in the same branch or pull request. This makes it more difficult to merge your changes.

Pull Requests

1. Create a new local branch.

# For a new feature
$ git checkout -b name-of-feature dev

# For a bugfix
$ git checkout -b fix-something 2.x-line

2. Commit your changes. Write good commit messages.

$ git commit -m "Detailed commit message"
$ git push origin name-of-feature
  1. Before submitting a pull request, check the following:
  • If the pull request adds functionality, it is tested and the docs are updated.
  • You’ve added yourself to AUTHORS.rst.
  1. Submit a pull request to marshmallow-code:dev or the appropriate maintenance branch. The Travis CI build must be passing before your pull request is merged.

Running tests

To run all tests:

$ invoke test

To run tests on Python 2.7, 3.4, 3.5, and PyPy virtual environments (must have each interpreter installed):

$ tox


Contributions to the documentation are welcome. Documentation is written in reStructured Text (rST). A quick rST reference can be found here. Builds are powered by Sphinx.

To install the packages for building the docs, run the following in the root of the project:

$ pip install -r docs/requirements.txt

To build the docs:

$ invoke docs -b

The -b (for “browse”) automatically opens up the docs in your browser after building.

You can also build the docs in “watch” mode:

$ pip install sphinx-autobuild
$ invoke docs -wb

Changes in the docs/ directory will automatically trigger a rebuild.

Contributing Examples

Have a usage example you’d like to share? A custom Field that others might find useful? Feel free to add it to the examples directory and send a pull request.