marshmallow

marshmallow is an ORM/ODM/framework-agnostic library for converting complex datatypes, such as objects, to and from native Python datatypes.

from datetime import date
from pprint import pprint

from marshmallow import Schema, fields


class ArtistSchema(Schema):
    name = fields.Str()


class AlbumSchema(Schema):
    title = fields.Str()
    release_date = fields.Date()
    artist = fields.Nested(ArtistSchema())


bowie = dict(name="David Bowie")
album = dict(artist=bowie, title="Hunky Dory", release_date=date(1971, 12, 17))

schema = AlbumSchema()
result = schema.dump(album)
pprint(result, indent=2)
# { 'artist': {'name': 'David Bowie'},
#   'release_date': '1971-12-17',
#   'title': 'Hunky Dory'}

In short, marshmallow schemas can be used to:

Validate input data.
Deserialize input data to app-level objects.
Serialize app-level objects to primitive Python types. The serialized objects can then be rendered to standard formats such as JSON for use in an HTTP API.

Get it now

$ pip install -U marshmallow

Documentation

Full documentation is available at https://marshmallow.readthedocs.io/ .

Ecosystem

A list of marshmallow-related libraries can be found at the GitHub wiki here:

https://github.com/marshmallow-code/marshmallow/wiki/Ecosystem

Credits

Contributors

This project exists thanks to all the people who contribute.

You’re highly encouraged to participate in marshmallow’s development. Check out the Contributing Guidelines to see how you can help.

Thank you to all who have already contributed to marshmallow!

Backers

If you find marshmallow useful, please consider supporting the team with a donation. Your donation helps move marshmallow forward.

Thank you to all our backers! [Become a backer]

Professional Support

Professionally-supported marshmallow is now available through the Tidelift Subscription.

Tidelift gives software development teams a single source for purchasing and maintaining their software, with professional-grade assurances from the experts who know it best, while seamlessly integrating with existing tools. [Get professional support]

Project Links

Docs: https://marshmallow.readthedocs.io/
Changelog: https://marshmallow.readthedocs.io/en/latest/changelog.html
Contributing Guidelines: https://github.com/marshmallow-code/.github/blob/main/CONTRIBUTING.md
PyPI: https://pypi.org/project/marshmallow/
Issues: https://github.com/marshmallow-code/marshmallow/issues
Donate: https://opencollective.com/marshmallow

License

MIT licensed. See the bundled LICENSE file for more details.

Release files for marshmallow 4.3.1

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for marshmallow 4.3.1
File	Size	Uploaded
marshmallow-4.3.1.tar.gz	218.3 kB	Aug 8, 2026	Details

Built distribution (wheel)

Table of built distributions (wheels) for marshmallow 4.3.1
File	Interpreter	ABI	Platform	Reset
marshmallow-4.3.1-py3-none-any.whl 49.2 kB Aug 8, 2026	Python 3	none	any	Details

Total release size:267.5 kB

Release files / marshmallow-4.3.1.tar.gz

Download URL	marshmallow-4.3.1.tar.gz
Size	218.3 kB
Tags	Source
SHA-256 checksum How to use checksums	`fb6b8048af08d4ab061610d5b7d3696a7e4c95337dbda880edb9f95812cabc20`
BLAKE2b-256 checksum How to use checksums	`4ed7611e68d57e6a903c29cb33b5afec0f93b4baecacc6c6c62e33cde9eb9dcb`
Upload date	Aug 8, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/marshmallow-code/marshmallow
Publishing commit: github.com/marshmallow-code/marshmallow/tree/c7b559a1fa3aba57ca6dba0ab336841c5038a782

Workflow

Publishing configuration: github.com/marshmallow-code/marshmallow/blob/c7b559a1fa3aba57ca6dba0ab336841c5038a782/.github/workflows/build-release.yml
Publishing logs: github.com/marshmallow-code/marshmallow/actions/runs/31261948061/attempts/1

Artifact

Subject: marshmallow-4.3.1.tar.gz
SHA-256 checksum: fb6b8048af08d4ab061610d5b7d3696a7e4c95337dbda880edb9f95812cabc20 Verifying attestations

Release files / marshmallow-4.3.1-py3-none-any.whl

Download URL	marshmallow-4.3.1-py3-none-any.whl
Size	49.2 kB
Tags	Python 3
SHA-256 checksum How to use checksums	`e65accfbe277546df92ed7996a678c90e063e9a7c2a2f5e03f7d0b90e3768c42`
BLAKE2b-256 checksum How to use checksums	`43574526ca0e214a3d158690e3393f6d547a2f8070f88d6388ab21d5b0aac8a1`
Upload date	Aug 8, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/marshmallow-code/marshmallow
Publishing commit: github.com/marshmallow-code/marshmallow/tree/c7b559a1fa3aba57ca6dba0ab336841c5038a782

Workflow

Publishing configuration: github.com/marshmallow-code/marshmallow/blob/c7b559a1fa3aba57ca6dba0ab336841c5038a782/.github/workflows/build-release.yml
Publishing logs: github.com/marshmallow-code/marshmallow/actions/runs/31261948061/attempts/1

Artifact

Subject: marshmallow-4.3.1-py3-none-any.whl
SHA-256 checksum: e65accfbe277546df92ed7996a678c90e063e9a7c2a2f5e03f7d0b90e3768c42 Verifying attestations