No known security advisories.
The current version has no OSV.dev malware reports and no critical or high-severity vulnerabilities.
zarr has 10.5M monthly downloads and 2K GitHub stars. Version 3.2.1 supports Python 3.12+, first published in 2015.
It is actively maintained under a permissive license, last released in May 2026.
It is built on top of donfig, google-crc32c and numcodecs. It is used by 880 tracked packages, including anndata, ome-zarr and icechunk.
GitHub topics include zarr, ndimensional-arrays and compressed.
Package Insights
Score breakdown - each component scores 0-100, weighted by percentage
Maintenance
100
Popularity
72
Adoption
60
Community
90
Provenance
100
How the maintenance status was determined
Last commit
0 days ago
Monthly downloads
10,531,892
•
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
10,531,892
Stars
2,008
Stars per 1k downloads
0.19
•
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
200,473
Month daily avg
351,063
Momentum
-42.9%
((week_daily_avg - month_daily_avg) / month_daily_avg) * 100Python version support tiers
requires_python
>=3.12
•
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
MIT
•
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
62 days ago
Total releases
117
Releases/year
11.1
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
168
Monthly downloads
10,531,892
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
96
Issue Burden
203.2
per 1k stars
Discussions
78.2
per 1k stars
Fork Ratio
39.7%
contrib / forks
Stale Release
61d
PR Velocity
Active
Weekly Downloads
GitHub Stars
Not all downloads include detailed metadata. Breakdowns reflect the subset that does.
Downloads by OS
Linux
126.4K
macOS
3.6K
Windows
3.0K
Python Versions
3.12
38.8%
50.9K
3.13
31.3%
41.1K
3.11
20.3%
26.7K
3.10
5.7%
7.4K
3.14
4.0%
5.2K
Top Countries
1.
US
97.0K
US
2.
IE
6.2K
IE
3.
GB
5.2K
GB
4.
BE
3.7K
BE
5.
SG
3.5K
SG
6.
NL
3.3K
NL
7.
CN
2.8K
CN
8.
CA
2.8K
CA
9.
DE
2.4K
DE
10.
ID
1.5K
ID
Dependencies
6
- donfig >=0.8
- google-crc32c >=1.5
- numcodecs >=0.14
- numpy >=2
- packaging >=22.0
- typing-extensions >=4.13
6 optional dependencies
- cast-value-rs[cast-value-rs]
- cupy-cuda12x[gpu]
- fsspec[remote]
- obstore[remote]
- typer[cli]
- universal-pathlib[optional]
Used By
880
- anndata
- ome-zarr
- icechunk
- nutpie
- copernicusmarine
- reproject
- spatialdata
- kerchunk
- multiscale-spatial-image
- xarray-tensorstore
- dandi
- satpy
- squidpy
- gandlf
- virtualizarr
- arraylake
- spikeinterface
- hdmf-zarr
- pycat-napari
- tiffslide
- ome-zarr-models
- large-image-source-tifffile
- ngff-zarr
- nvidia-ncore
- titiler-xarray
- large-image-source-zarr
- intake-esm
- anemoi-datasets
- virtual-tiff
- zarrs
- geff
- intake-xarray
- rechunker
- geff-spec
- nuthatch
- asgard-eopf
- nvalchemi-toolkit
- aef-loader
- bioio-ome-zarr
- xpublish-tiles
- scib
- patchworks
- nlr-revrt
- vitessce
- lazy-ops
- xarray-beam
- pyzfn
- scimap
- mmpp
- bfio
GitHub Topics
Tags from the package's GitHub repository describing what it does.
Package Information
License
MIT
First Release
December 18, 2015
Last Release
2 months ago
Last Commit
18 hr ago
Latest Version
3.2.1
Total Releases
117
Contributors
168
Open PRs
107
Archived
No
Python Versions
3
3.12
3.13
3.14
Wheels
py3
Keywords
Tracking Since
January 6, 2026
Data Updated
July 5, 2026
Data Freshness
Fresh