No known security advisories.
The current version has no OSV.dev malware reports and no critical or high-severity vulnerabilities.
msgspec has 42.6M monthly downloads and 4K GitHub stars. Version 0.21.1 supports Python 3.10+, first published in 2021.
It is actively maintained under a permissive license, last released in Apr 2026.
It is used by 729 tracked packages, including sglang, flask-session and apache-airflow-core.
GitHub topics include msgpack, serialization and json.
Package Insights
Score breakdown - each component scores 0-100, weighted by percentage
Maintenance
100
Popularity
72
Adoption
70
Community
60
Provenance
100
How the maintenance status was determined
Last commit
3 days ago
Monthly downloads
42,637,867
•
Active
Activity within 30 days
Stable
Activity within 31-180 days
Minimal
Activity within 181-365 days, or no activity data
At Risk
No activity for > 365 days, but > 10,000 monthly downloads
Archived
Repository flagged as archived on GitHub
How the popularity category was determined
Monthly downloads
42,637,867
Stars
3,845
Stars per 1k downloads
0.09
•
Industry Standard
> 10,000,000 monthly downloads
Hidden Gem
< 0.5 stars per 1k downloads and > 100,000 monthly downloads
Community Favorite
> 5 stars per 1k downloads
Rising Star
Balanced ratio of stars to downloads
Unknown
Fewer than 1,000 monthly downloads, or no star data
How download momentum is calculated
Week daily avg
1,302,822
Month daily avg
1,421,262
Momentum
-8.3%
((week_daily_avg - month_daily_avg) / month_daily_avg) * 100Python version support tiers
requires_python
>=3.10
Cutting Edge
Minimum supported version is 3.12 or newer
•
Modern
Minimum supported version is 3.9, 3.10, or 3.11
Legacy
Supports 3.8 or older (or Python 2)
Unknown
No requires_python specified or unparseable
License categories
License
BSD-3-Clause
•
Permissive
MIT, Apache, BSD, ISC, Unlicense, CC0, etc.
Copyleft
GPL, LGPL, AGPL, MPL, EPL, etc.
Proprietary
Commercial, all rights reserved, custom EULAs
Unknown
No license specified, or none of the above match
How the release cadence was determined
Last release
84 days ago
Total releases
40
Releases/year
7.5
Rapid
Last release within 365 days and > 12 releases/year
•
Regular
Last release within 365 days
Slow
Last release 366-730 days ago
Stalled
Last release > 730 days ago, or no releases
Unknown
No usable release date available
How contributor risk was determined
Contributors
58
Monthly downloads
42,637,867
High Load
≤ 2 contributors and ≥ 50,000 monthly downloads
Moderate Load
< 10 contributors and ≥ 500,000 monthly downloads
Low Load
< 25 contributors and ≥ 5,000,000 monthly downloads, or sole maintainer with ≥ 10,000 monthly downloads
•
Balanced
Enough contributors for the package's popularity
Unknown
No contributor data available
Engagement
55
Issue Burden
48.1
per 1k stars
Discussions
0.0
per 1k stars
Fork Ratio
37.2%
contrib / forks
Stale Release
81d
PR Velocity
Quiet
Weekly Downloads
GitHub Stars
Not all downloads include detailed metadata. Breakdowns reflect the subset that does.
Downloads by OS
Linux
739.3K
macOS
9.9K
Windows
9.2K
Python Versions
3.12
28.8%
215.6K
3.10
25.9%
193.9K
3.11
24.5%
183.1K
3.13
13.5%
100.8K
3.14
7.3%
54.6K
Top Countries
1.
US
654.1K
US
2.
DE
14.6K
DE
3.
NL
11.1K
NL
4.
TH
10.6K
TH
5.
IE
9.3K
IE
6.
KR
9.2K
KR
7.
GB
8.4K
GB
8.
SG
7.2K
SG
9.
JP
5.4K
JP
10.
IN
5.2K
IN
Used By
729
- sglang
- flask-session
- apache-airflow-core
- pinecone
- apache-airflow-task-sdk
- vllm
- marimo
- litestar
- angr
- unsloth-zoo
- viser
- pytype
- taskcluster-taskgraph
- pyatlan
- vkbottle-types
- aiperf
- nautilus-trader
- msgspec-click
- dda
- vllm-cpu
- gem-llm
- prophecy-libs
- snowpipe-streaming
- aistore
- cocoindex
- lmcache
- ick
- flare-capa
- lmstudio
- vllm-tpu
- evm-trace
- mantis-agent-sdk
- realit-singer-python
- qubx
- ai-dynamo
- python-datamodel
- starlite
- sentry-scm
- betfair-parser
- vaxrank
- persist-cache
- transferqueue
- uncountablepythonsdk
- taksonomia
- dolma
- toolr-py
- satori-ci
- proxen
- anbor-types
- arvel
GitHub Topics
Tags from the package's GitHub repository describing what it does.
Package Information
License
BSD-3-Clause
First Release
February 23, 2021
Last Release
2 months ago
Last Commit
3 days ago
Latest Version
0.21.1
Total Releases
40
Contributors
58
Open PRs
21
Archived
No
Python Versions
3.10
3.11
3.12
3.13
3.14
Wheels
cp310
cp311
cp312
cp313
cp314
cp38
cp39
Keywords
Tracking Since
January 6, 2026
Data Updated
July 5, 2026
Data Freshness
Fresh