Python recommendation tools

Conda Version

LensKit is a set of Python tools for experimenting with and studying recommender systems. It provides support for training, running, and evaluating recommender algorithms in a flexible fashion suitable for research and education.

LensKit for Python (LKPY) is the successor to the Java-based LensKit project.

[!IMPORTANT] If you use LensKit for Python in published research, please cite:

Michael D. Ekstrand. 2020. LensKit for Python: Next-Generation Software for Recommender Systems Experiments. In Proceedings of the 29th ACM International Conference on Information and Knowledge Management (CIKM '20). DOI:10.1145/3340531.3412778. arXiv:1809.03125 [cs.IR].

[!NOTE]

LensKit had significant changes in the 2025.1 release. See the Migration Guide for details.

Installing

To install the current release with uv (recommended):

$ uv pip install lenskit

Or, to add it to your project's dependencies and virtual environment:

$ uv add lenskit

Classic pip also works:

$ python -m pip install lenskit

Then see Getting Started

Conda Packages

You can also install LensKit from conda-forge with pixi:

$ pixi add lenskit

Or conda:

$ conda install -c conda-forge lenskit

Development Version

To use the latest development version, you have two options. You can install directly from GitHub:

$ uv pip install -U git+https://github.com/lenskit/lkpy

Or you can use our PyPI index, by adding to pyproject.toml:

[[tool.uv.index]]
name = "lenskit"
url = "https://pypi.lenskit.org/lenskit-dev/"

Binary wheels of LensKit development (and release) versions are automatically pushed to this index, although they are not guaranteed to be permanently available. Reproducible code should generally depend on released versions published to PyPI.

Simplifying PyTorch installation

We also provide mirrors of the PyTorch package repositories that are filtered to only include PyTorch and directly supporting dependencies, without other packages that conflict with or mask packages from PyPI, and with fallbacks for other platforms (i.e., our CUDA indices include CPU-only MacOS packages). This makes it easier to install specific versions of PyTorch in your project with the index priority and fallthrough logic implemented by uv. To make your project only use CPU-based PyTorch, you can add to pyproject.toml:

[[tool.uv.index]]
name = "torch-cpu"
url = "https://pypi.lenskit.org/torch/cpu/"

Or CUDA 12.8:

[[tool.uv.index]]
name = "torch-gpu"
url = "https://pypi.lenskit.org/torch/cu128/"

These indices provide the same package distributions as the official PyTorch repositories (in fact, they link directly to the PyTorch packages). They are just an alternate index view that reduces some package conflicts.

Developing

To contribute to LensKit, clone or fork the repository, get to work, and submit a pull request. We welcome contributions from anyone; if you are looking for a place to get started, see the issue tracker.

Our development workflow is documented in the wiki; the wiki also contains other information on developing LensKit. User-facing documentation is at https://lkpy.lenskit.org.

We use uv for developing LensKit and managing development environments. Our pyproject.toml file contains the Python development dependencies; you also need a working Rust compiler (typically via rustup). Before setting up to work on LensKit, you therefore need:

Git
uv
rustup and a working Rust compiler (rustup install stable)
A working C compiler compatible with Python
- On Windows, this is either Visual Studio (with C++ development) or the Visual C++ Build Tools. See the Rustup Windows install instructions for details.
- On Mac, install Xcode.
- On Linux, see your system package manager instructions.

Windows

On Windows, you can install dependencies (except for the Visual C++ tools) with winget:

> winget install Git.Git astral-sh.uv Rustlang.Rustup
> rustup install stable-msvc

Mac

On Mac, you can install the dependencies with Homebrew:

$ brew install git uv rustup

Once you have the dependencies installed, set up your LensKit development environment:

$ uv venv -p 3.12
$ uv sync

If you want all extras (may not work on Windows), do:

$ uv sync --all-extras

You can then activate the virtual environment to have the tools available and run tools like pytest:

$ . ./.venv/bin/activate

Testing Changes

You should always test your changes by running the LensKit test suite:

pytest tests

If you want to use your changes in a LensKit experiment, you can locally install your modified LensKit into your experiment's environment. We recommend using separate environments for LensKit development and for each experiment; you will need to install the modified LensKit into your experiment's repository:

uv pip install -e /path/to/lkpy

Resources

Acknowledgements

This material is based upon work supported by the National Science Foundation under Grant No. IIS 17-51278. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

lenskit-2025.8.1.tar.gz (3.0 MB view details)

Uploaded Jul 13, 2026 Source

Built Distributions

If you're not sure about the file name format, learn more about wheel file names.

The dropdown lists show the available interpreters, ABIs, and platforms. Enable javascript to be able to filter the list of wheel files.

lenskit-2025.8.1-cp311-abi3-win_amd64.whl (2.7 MB view details)

Uploaded Jul 13, 2026 CPython 3.11+Windows x86-64

lenskit-2025.8.1-cp311-abi3-win32.whl (2.5 MB view details)

Uploaded Jul 13, 2026 CPython 3.11+Windows x86

lenskit-2025.8.1-cp311-abi3-manylinux_2_28_x86_64.whl (7.9 MB view details)

Uploaded Jul 13, 2026 CPython 3.11+manylinux: glibc 2.28+ x86-64

lenskit-2025.8.1-cp311-abi3-manylinux_2_28_aarch64.whl (7.4 MB view details)

Uploaded Jul 13, 2026 CPython 3.11+manylinux: glibc 2.28+ ARM64

lenskit-2025.8.1-cp311-abi3-macosx_11_0_arm64.whl (2.5 MB view details)

Uploaded Jul 13, 2026 CPython 3.11+macOS 11.0+ ARM64

lenskit-2025.8.1-cp311-abi3-macosx_10_12_x86_64.whl (2.8 MB view details)

Uploaded Jul 13, 2026 CPython 3.11+macOS 10.12+ x86-64

File details

Details for the file lenskit-2025.8.1.tar.gz.

File metadata

Download URL: lenskit-2025.8.1.tar.gz
Upload date: Jul 13, 2026
Size: 3.0 MB
Tags: Source
Uploaded using Trusted Publishing? Yes
Uploaded via: twine/6.1.0 CPython/3.13.12

File hashes

Hashes for lenskit-2025.8.1.tar.gz
Algorithm	Hash digest
SHA256	`954b22a81e8a0d2012a173340079aa3d0c68dcc8cb9954e488fc228d77d4cb55`
MD5	`981bfab15b8fffc1c029134e77c3ed2c`
BLAKE2b-256	`85d4b0f120bd01fe614520281afd21b80b4222ef138e687f861a3f3ea4bbab7a`

See more details on using hashes here.

Provenance

The following attestation bundles were made for lenskit-2025.8.1.tar.gz:

Publisher: package.yml on lenskit/lkpy

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Statement:
- Statement type: https://in-toto.io/Statement/v1
- Predicate type: https://docs.pypi.org/attestations/publish/v1
- Subject name: lenskit-2025.8.1.tar.gz
- Subject digest: 954b22a81e8a0d2012a173340079aa3d0c68dcc8cb9954e488fc228d77d4cb55
- Sigstore transparency entry: 2163729394
- Sigstore integration time: Jul 13, 2026
Source repository:
- Permalink: lenskit/lkpy@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Branch / Tag: refs/tags/v2025.8.1
- Owner: https://github.com/lenskit
- Access: public
Publication detail:
- Token Issuer: https://token.actions.githubusercontent.com
- Runner Environment: github-hosted
- Publication workflow: package.yml@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Trigger Event: release

File details

Details for the file lenskit-2025.8.1-cp311-abi3-win_amd64.whl.

File metadata

Download URL: lenskit-2025.8.1-cp311-abi3-win_amd64.whl
Upload date: Jul 13, 2026
Size: 2.7 MB
Tags: CPython 3.11+, Windows x86-64
Uploaded using Trusted Publishing? Yes
Uploaded via: twine/6.1.0 CPython/3.13.12

File hashes

Hashes for lenskit-2025.8.1-cp311-abi3-win_amd64.whl
Algorithm	Hash digest
SHA256	`7e30cc3ba9492b257ef8ed67352ccfba812aa6cb09b5da28ace9eaec33f8e957`
MD5	`c02822cd56b81f9306dfb85edcbbbee7`
BLAKE2b-256	`9f9bde17cdc0ba140ab1242c2de168d05af8a97d3e139666e9e335ad4c6a2c4c`

See more details on using hashes here.

Provenance

The following attestation bundles were made for lenskit-2025.8.1-cp311-abi3-win_amd64.whl:

Publisher: package.yml on lenskit/lkpy

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Statement:
- Statement type: https://in-toto.io/Statement/v1
- Predicate type: https://docs.pypi.org/attestations/publish/v1
- Subject name: lenskit-2025.8.1-cp311-abi3-win_amd64.whl
- Subject digest: 7e30cc3ba9492b257ef8ed67352ccfba812aa6cb09b5da28ace9eaec33f8e957
- Sigstore transparency entry: 2163729403
- Sigstore integration time: Jul 13, 2026
Source repository:
- Permalink: lenskit/lkpy@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Branch / Tag: refs/tags/v2025.8.1
- Owner: https://github.com/lenskit
- Access: public
Publication detail:
- Token Issuer: https://token.actions.githubusercontent.com
- Runner Environment: github-hosted
- Publication workflow: package.yml@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Trigger Event: release

File details

Details for the file lenskit-2025.8.1-cp311-abi3-win32.whl.

File metadata

Download URL: lenskit-2025.8.1-cp311-abi3-win32.whl
Upload date: Jul 13, 2026
Size: 2.5 MB
Tags: CPython 3.11+, Windows x86
Uploaded using Trusted Publishing? Yes
Uploaded via: twine/6.1.0 CPython/3.13.12

File hashes

Hashes for lenskit-2025.8.1-cp311-abi3-win32.whl
Algorithm	Hash digest
SHA256	`b993502d493f22d85af68685dd913135a1cd3bbbfc2c1c712292f54ebd8fde57`
MD5	`b8f23bce393f294c49c8a55cf1511c64`
BLAKE2b-256	`8cf7cfbb5b73bcf56aa0b091ae9e300732e4a3880ce276de8e74d130b660d38f`

See more details on using hashes here.

Provenance

The following attestation bundles were made for lenskit-2025.8.1-cp311-abi3-win32.whl:

Publisher: package.yml on lenskit/lkpy

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Statement:
- Statement type: https://in-toto.io/Statement/v1
- Predicate type: https://docs.pypi.org/attestations/publish/v1
- Subject name: lenskit-2025.8.1-cp311-abi3-win32.whl
- Subject digest: b993502d493f22d85af68685dd913135a1cd3bbbfc2c1c712292f54ebd8fde57
- Sigstore transparency entry: 2163729417
- Sigstore integration time: Jul 13, 2026
Source repository:
- Permalink: lenskit/lkpy@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Branch / Tag: refs/tags/v2025.8.1
- Owner: https://github.com/lenskit
- Access: public
Publication detail:
- Token Issuer: https://token.actions.githubusercontent.com
- Runner Environment: github-hosted
- Publication workflow: package.yml@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Trigger Event: release

File details

Details for the file lenskit-2025.8.1-cp311-abi3-manylinux_2_28_x86_64.whl.

File metadata

Download URL: lenskit-2025.8.1-cp311-abi3-manylinux_2_28_x86_64.whl
Upload date: Jul 13, 2026
Size: 7.9 MB
Tags: CPython 3.11+, manylinux: glibc 2.28+ x86-64
Uploaded using Trusted Publishing? Yes
Uploaded via: twine/6.1.0 CPython/3.13.12

File hashes

Hashes for lenskit-2025.8.1-cp311-abi3-manylinux_2_28_x86_64.whl
Algorithm	Hash digest
SHA256	`6b52753e0615a662b8b9ca470a6ddac63b6f3961fc1d9bc2005a1ca6c0da805c`
MD5	`e0bcdce10519cdade64a01edb9a21508`
BLAKE2b-256	`1499b9805ce607da87a006529f4a173ebcc87108854738bbb3d64bea517487a9`

See more details on using hashes here.

Provenance

The following attestation bundles were made for lenskit-2025.8.1-cp311-abi3-manylinux_2_28_x86_64.whl:

Publisher: package.yml on lenskit/lkpy

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Statement:
- Statement type: https://in-toto.io/Statement/v1
- Predicate type: https://docs.pypi.org/attestations/publish/v1
- Subject name: lenskit-2025.8.1-cp311-abi3-manylinux_2_28_x86_64.whl
- Subject digest: 6b52753e0615a662b8b9ca470a6ddac63b6f3961fc1d9bc2005a1ca6c0da805c
- Sigstore transparency entry: 2163729433
- Sigstore integration time: Jul 13, 2026
Source repository:
- Permalink: lenskit/lkpy@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Branch / Tag: refs/tags/v2025.8.1
- Owner: https://github.com/lenskit
- Access: public
Publication detail:
- Token Issuer: https://token.actions.githubusercontent.com
- Runner Environment: github-hosted
- Publication workflow: package.yml@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Trigger Event: release

File details

Details for the file lenskit-2025.8.1-cp311-abi3-manylinux_2_28_aarch64.whl.

File metadata

Download URL: lenskit-2025.8.1-cp311-abi3-manylinux_2_28_aarch64.whl
Upload date: Jul 13, 2026
Size: 7.4 MB
Tags: CPython 3.11+, manylinux: glibc 2.28+ ARM64
Uploaded using Trusted Publishing? Yes
Uploaded via: twine/6.1.0 CPython/3.13.12

File hashes

Hashes for lenskit-2025.8.1-cp311-abi3-manylinux_2_28_aarch64.whl
Algorithm	Hash digest
SHA256	`36766b3e5b056b9a44f7dc2c0526ddb24abe3ba0d84c2cd712cb0616137e88e9`
MD5	`e36d19f1ba5ae0b76f9d14fd37945fb5`
BLAKE2b-256	`d897af3e55512aa39a80eed828cd72817cdf23090e110c8063f552b10cfdb281`

See more details on using hashes here.

Provenance

The following attestation bundles were made for lenskit-2025.8.1-cp311-abi3-manylinux_2_28_aarch64.whl:

Publisher: package.yml on lenskit/lkpy

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Statement:
- Statement type: https://in-toto.io/Statement/v1
- Predicate type: https://docs.pypi.org/attestations/publish/v1
- Subject name: lenskit-2025.8.1-cp311-abi3-manylinux_2_28_aarch64.whl
- Subject digest: 36766b3e5b056b9a44f7dc2c0526ddb24abe3ba0d84c2cd712cb0616137e88e9
- Sigstore transparency entry: 2163729410
- Sigstore integration time: Jul 13, 2026
Source repository:
- Permalink: lenskit/lkpy@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Branch / Tag: refs/tags/v2025.8.1
- Owner: https://github.com/lenskit
- Access: public
Publication detail:
- Token Issuer: https://token.actions.githubusercontent.com
- Runner Environment: github-hosted
- Publication workflow: package.yml@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Trigger Event: release

File details

Details for the file lenskit-2025.8.1-cp311-abi3-macosx_11_0_arm64.whl.

File metadata

Download URL: lenskit-2025.8.1-cp311-abi3-macosx_11_0_arm64.whl
Upload date: Jul 13, 2026
Size: 2.5 MB
Tags: CPython 3.11+, macOS 11.0+ ARM64
Uploaded using Trusted Publishing? Yes
Uploaded via: twine/6.1.0 CPython/3.13.12

File hashes

Hashes for lenskit-2025.8.1-cp311-abi3-macosx_11_0_arm64.whl
Algorithm	Hash digest
SHA256	`99751dec434c8feb385c571e3388b8947332678fd130043410a07e05382d6a1e`
MD5	`ff1615453450adfe685e970bb81d8362`
BLAKE2b-256	`7b6582156f8110a4f50b7d03dbf2de445ca930bed15d052b656c3e5778a25cb8`

See more details on using hashes here.

Provenance

The following attestation bundles were made for lenskit-2025.8.1-cp311-abi3-macosx_11_0_arm64.whl:

Publisher: package.yml on lenskit/lkpy

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Statement:
- Statement type: https://in-toto.io/Statement/v1
- Predicate type: https://docs.pypi.org/attestations/publish/v1
- Subject name: lenskit-2025.8.1-cp311-abi3-macosx_11_0_arm64.whl
- Subject digest: 99751dec434c8feb385c571e3388b8947332678fd130043410a07e05382d6a1e
- Sigstore transparency entry: 2163729429
- Sigstore integration time: Jul 13, 2026
Source repository:
- Permalink: lenskit/lkpy@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Branch / Tag: refs/tags/v2025.8.1
- Owner: https://github.com/lenskit
- Access: public
Publication detail:
- Token Issuer: https://token.actions.githubusercontent.com
- Runner Environment: github-hosted
- Publication workflow: package.yml@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Trigger Event: release

File details

Details for the file lenskit-2025.8.1-cp311-abi3-macosx_10_12_x86_64.whl.

File metadata

Download URL: lenskit-2025.8.1-cp311-abi3-macosx_10_12_x86_64.whl
Upload date: Jul 13, 2026
Size: 2.8 MB
Tags: CPython 3.11+, macOS 10.12+ x86-64
Uploaded using Trusted Publishing? Yes
Uploaded via: twine/6.1.0 CPython/3.13.12

File hashes

Hashes for lenskit-2025.8.1-cp311-abi3-macosx_10_12_x86_64.whl
Algorithm	Hash digest
SHA256	`83eaba800d9919ce11448a9bd959cc4b2714769f67924976248c1e65e8872cc1`
MD5	`48e576b3b2f741218228f16e8eed3820`
BLAKE2b-256	`b193767f9f64b04af487387055ab0ccdb5772f59fdcb87d983de3421c9ebe0f2`

See more details on using hashes here.

Provenance

The following attestation bundles were made for lenskit-2025.8.1-cp311-abi3-macosx_10_12_x86_64.whl:

Publisher: package.yml on lenskit/lkpy

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Statement:
- Statement type: https://in-toto.io/Statement/v1
- Predicate type: https://docs.pypi.org/attestations/publish/v1
- Subject name: lenskit-2025.8.1-cp311-abi3-macosx_10_12_x86_64.whl
- Subject digest: 83eaba800d9919ce11448a9bd959cc4b2714769f67924976248c1e65e8872cc1
- Sigstore transparency entry: 2163729423
- Sigstore integration time: Jul 13, 2026
Source repository:
- Permalink: lenskit/lkpy@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Branch / Tag: refs/tags/v2025.8.1
- Owner: https://github.com/lenskit
- Access: public
Publication detail:
- Token Issuer: https://token.actions.githubusercontent.com
- Runner Environment: github-hosted
- Publication workflow: package.yml@8227b0f175d1d685b3527a7d0cf8164dd32fe049
- Trigger Event: release

Release history Release notifications | RSS feed

2026.3.0

Aug 6, 2026

2026.3.0b1 pre-release

Jul 30, 2026

2026.2.1

Jun 1, 2026

2026.2.0

May 25, 2026

2026.1.0

Apr 18, 2026

2026.1.0b1 pre-release

Apr 16, 2026

This release

2025.8.1

Jul 13, 2026

2025.8.0

Apr 16, 2026

2025.7.0

Mar 20, 2026

2025.7.0b1 pre-release

Feb 26, 2026

2025.6.3

Jan 15, 2026

2025.6.2

Dec 8, 2025

2025.6.1

Nov 17, 2025

2025.6.0

Nov 16, 2025

2025.5.0

Nov 13, 2025

2025.4.0

Oct 22, 2025

2025.3.2

Oct 14, 2025

2025.3.1

Oct 8, 2025

2025.3.0a3.post1 pre-release

May 20, 2025

2025.3.0a2.post2 pre-release

Apr 16, 2025

2025.2.0

Mar 12, 2025

2025.1.1

Mar 8, 2025

2025.1.1rc5 pre-release

Mar 4, 2025

2025.1.1rc4 pre-release

Mar 3, 2025

2025.1.1rc3 pre-release

Mar 1, 2025

2025.1.1rc2 pre-release

Feb 28, 2025

2025.1.1rc1 pre-release

Feb 27, 2025

2025.1.1b12 pre-release

Feb 22, 2025

2025.1.1b11 pre-release

Feb 19, 2025

2025.1.1b10 pre-release

Feb 18, 2025

2025.1.1b9 pre-release

Feb 11, 2025

2025.1.1b8 pre-release

Feb 6, 2025

2025.1.1b7 pre-release

Feb 6, 2025

2025.1.1b6 pre-release

Feb 6, 2025

2025.1.1b5 pre-release

Feb 5, 2025

2025.1.1b4 pre-release

Feb 4, 2025

2025.1.1b3 pre-release

Feb 2, 2025

2025.1.1b2 pre-release

Feb 1, 2025

2025.1.0b1 pre-release

Jan 21, 2025

2025.0.0a6 pre-release

Jan 14, 2025

2025.0.0a5 pre-release

Jan 14, 2025

2025.0.0a4 pre-release

Jan 10, 2025

2025.0.0a3 pre-release

Jan 7, 2025

2025.0.0a2 pre-release

Dec 31, 2024

2025.0.0a1 pre-release

Dec 25, 2024

0.14.4

Feb 16, 2024

0.14.3

Jan 22, 2024

0.14.2

Aug 16, 2022

0.14.1

Mar 11, 2022

0.14.0

Feb 19, 2022

0.13.1

Jun 22, 2021

0.13.0

Jun 18, 2021

0.12.3

Mar 6, 2021

0.12.1

Mar 2, 2021

0.12.0

Feb 13, 2021

0.11.1

Nov 13, 2020

0.11.0

Nov 13, 2020

0.10.1

Jun 27, 2020

0.10.0

Jun 9, 2020

0.9.0

May 26, 2020

0.8.4

Jan 9, 2020

0.8.1

Dec 10, 2019

0.8.0

Dec 10, 2019

0.7.0

May 19, 2019

0.6.1

Apr 3, 2019

0.6.0

Mar 2, 2019

0.5.0

Jan 13, 2019

0.3.0

Nov 27, 2018

0.2.0

Sep 20, 2018

0.1.0

Jul 29, 2018

lenskit 2025.8.1

Python recommendation tools

Installing

Conda Packages

Development Version

Simplifying PyTorch installation

Developing

Testing Changes

Resources

Acknowledgements

Project links

Key dates

1 maintainer

Credits

GitHub Statistics

License expression

Requires

Provides Extra

Classifiers

Download files

Source Distribution

Built Distributions

File details

File metadata

File hashes

Provenance

File details

File metadata

File hashes

Provenance

File details

File metadata

File hashes

Provenance

File details

File metadata

File hashes

Provenance

File details

File metadata

File hashes

Provenance

File details

File metadata

File hashes

Provenance

File details

File metadata

File hashes

Provenance

Release history Release notifications | RSS feed