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simplejson

Simple, fast, extensible JSON encoder/decoder for Python

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jsonjson-parserjson-serializerpythonpython2python3
github.com/simplejson/simplejsonMITBob Ippolito11.4M / week1.7k · 367 forks · 61 contributors
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Compares against 4.2.0 (latest stable)
Latest Stable4.2.0Oct 3, 2026
Release cadenceEvery 4 months
Last releaseOct 3, 2026
Open advisories0
Changelog quality28% curated
GitHub Releases, gaps for some releases
Release history SecurityYou're on
3.x4.x
STABLE · RCPRE-RELEASE2024AprJulOct2025AprJulOct2026AprJulOct

103 older or filtered releases not shown.

Upgrade guides

Breaking changes and a migration checklist for each major version
simplejson 3 → 43.20.2 → 4.2.0Oct 3, 2026 BreakingPlatform2New7Changed6Fixed11Other12simplejson 2 → 32.6.2 → 3.20.2Sep 26, 2025 BreakingBreaking2Security2Platform3New1Changed7Fixed13Other20simplejson 1 → 21.9.3 → 2.6.2Sep 21, 2012 UnknownSecurity1
VersionChannelDateChangesSecurity
4.2.0 StableOct 3, 2026New1Changed1Fixed2Other24.1.2 youStableAug 27, 2026Fixed44.1.1 StableApr 24, 2026Other14.1.0 StableApr 22, 2026Changed14.0.1 StableApr 18, 2026Other14.0.0 StableApr 18, 2026Platform2New6Changed4Fixed5Other83.20.2 StableSep 26, 2025Changed1Other23.20.1 StableFeb 15, 2025Fixed13.19.3 StableAug 14, 2024Platform13.19.2 StableOct 6, 2023Other13.19.1 StableApr 6, 2023Breaking2Security2Fixed3Other23.18.4 StableMar 14, 2023Other23.18.3 StableFeb 5, 2023Fixed13.18.2 StableFeb 5, 2023Other13.18.1 StableJan 3, 2023Platform1Other13.18.0 StableNov 14, 2022Changed1Fixed13.17.6 StableNov 16, 2021Platform13.17.5 StableAug 24, 2021Fixed13.17.4 StableAug 20, 2021Other13.17.3 StableJul 9, 2021Other1