PyPI
marshmallow
A lightweight library for converting complex datatypes to and from native Python datatypes.
deserializationmarshallingpythonschemaserdeserializationvalidation
github.com/marshmallow-code/marshmallowMITSteven Loria21.1M / week7.2k · 770 forks · 230 contributors
Release cadenceEvery 2 weeks
Last releaseAug 8, 2026
Open advisories0
Changelog quality100% curated
CHANGELOG
Release history SecurityYou're on
171 older or filtered releases not shown.
Upgrade guides
Breaking changes and a migration checklist for each major versionmarshmallow 3 → 43.26.2 → 4.3.1Aug 8, 2026 BreakingBreaking29Security1Platform1New5Changed7Fixed17Other1marshmallow 2 → 32.21.0 → 3.26.2Dec 22, 2025 BreakingBreaking53Security2Platform9Deprecated14New38Changed35Fixed86Other40marshmallow 1 → 21.2.6 → 2.21.0Mar 5, 2020 BreakingBreaking30Security1Platform3Deprecated13New45Changed22Fixed79Other14marshmallow 0.7 → 10.7.0 → 1.2.6May 3, 2015 BreakingBreaking9Deprecated3New15Changed12Fixed28Other11marshmallow 0.6 → 0.70.6.0 → 0.7.0Jun 22, 2014 Review neededDeprecated1New2Changed3Fixed1marshmallow 0.5 → 0.60.5.5 → 0.6.0Jun 4, 2014 Review neededNew1Changed1Fixed1marshmallow 0.4 → 0.50.4.1 → 0.5.5May 3, 2014 BreakingBreaking2New13Changed5Fixed2Other1marshmallow 0.3 → 0.40.3.1 → 0.4.1Dec 2, 2013 BreakingBreaking5New4Changed3Fixed4marshmallow 0.2 → 0.30.2.1 → 0.3.1Nov 16, 2013 BreakingBreaking2New4Changed1Fixed2Other1marshmallow 0.1 → 0.20.1.0 → 0.2.1Nov 12, 2013 BreakingPlatform1New6Fixed1
VersionChannelDateChangesSecurity
4.3.1 StableAug 8, 2026Changed1Fixed14.3.0 StableApr 3, 2026New1Changed14.2.4 youStableApr 2, 2026Fixed34.2.3 StableMar 25, 2026New1Fixed74.2.2 StableFeb 4, 2026Fixed14.2.1 StableJan 23, 2026Fixed14.2.0 StableJan 4, 2026Fixed14.1.2 StableDec 22, 2025Security1Fix4.1.1 StableDec 5, 2025Fixed14.1.0 StableNov 1, 2025Platform1New1Other14.0.1 StableAug 28, 2025Fixed14.0.0 StableApr 17, 2025Breaking29New2Changed5Fixed13.26.2 StableDec 22, 2025Security1Fix3.26.1 StableFeb 3, 2025Changed1Fixed13.26.0 StableJan 23, 2025Deprecated1Changed3Fixed3Other23.25.1 StableJan 11, 2025Fixed2Other13.25.0 StableJan 9, 2025Deprecated1Changed1Fixed13.24.2 StableJan 8, 2025Fixed1Other13.24.1 StableJan 7, 2025Fixed13.24.0 StableJan 6, 2025Deprecated3Changed1Fixed1Other1