openslide-python
Python interface to OpenSlide
Decision gist · record as of 2026-08-14
Yes, if you work with whole-slide images in digital pathology or medical research. The package is actively maintained, well-supported across platforms and Python versions, and solves a specialized but critical problem—standard image libraries cannot handle these formats or their scale. The main gotcha is the separate OpenSlide C library dependency. No known vulnerabilities.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- OpenSlide C library (≥3.4.0) must be installed separately; installation method varies by platform.
- Medium install friction due to a compiled C dependency (OpenSlide library) that must be installed separately.
- The project is actively maintained with recent releases, and wheels are provided for multiple Python versions and platforms (macOS, Linux, Windows, including aarch64).
License · maintenance · safety
LGPL-2.1-only AND BSD-3-Clause AND MIT AND LicenseRef-Public-Domain (copyleft) — Licensed under LGPL-2.1-only with additional BSD-3-Clause, MIT, and public domain components. The copyleft LGPL treatment means derivative works must be licensed compatibly, though linking from a proprietary application is generally permitted if OpenSlide is dynamically linked.
last release 2026-06-08 (67 days) · last repo commit 2026-08-09 · 432 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 270,441 downloads/mo, #8,236 on PyPI
Alternatives
Verify before relying
pip install openslide-python
from openslide import OpenSlide
slide = OpenSlide('path/to/slide.svs')
region = slide.read_region((x, y), level, (width, height))- Whether the OpenSlide C library (≥3.4.0) is pre-installed on target systems or must be managed separately in deployment
- Performance characteristics and memory efficiency when handling specific gigabyte-scale slide formats in production
- Recommended installation method for the separate OpenSlide C library dependency on different platforms
What it is and what it does
OpenSlide Python wraps the OpenSlide C library to read whole-slide images—the massive, multi-resolution medical images used in digital pathology. These images can occupy tens of gigabytes uncompressed and come in proprietary formats from vendors like Aperio, Hamamatsu, Leica, Philips, Zeiss, and others; standard image tools cannot handle them. The library lets you read image data at the resolution closest to a desired zoom level without loading the entire file into RAM.
The package depends on Pillow for image handling and requires Python ≥3.10 and a separate OpenSlide C library installation (≥3.4.0). It supports formats including Aperio, ARGOS, DICOM, Hamamatsu, Huron, Leica, MIRAX, Philips, Sakura, Trestle, Ventana, Zeiss, and generic tiled TIFF, and is actively maintained with wheels for modern Python versions and multiple architectures.
Use it for
- Load and tile whole-slide images for web-based pathology viewers or deep-learning training pipelines
- Extract regions of interest at specific zoom levels from gigabyte-scale slides in vendor formats
- Build automated image analysis workflows that process whole-slide images without memory exhaustion
- Integrate multi-resolution slide access into clinical decision-support or research annotation tools
- Work with DICOM or CZI slides in medical imaging applications
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you work with whole-slide images in digital pathology or medical research.
The package is actively maintained, well-supported across platforms and Python versions, and solves a specialized but critical problem—standard image libraries cannot handle these formats or their scale. The main gotcha is the separate OpenSlide C library dependency. No known vulnerabilities.
Install
openslide-python on PyPI
Before you install
Medium install friction due to a compiled C dependency (OpenSlide library) that must be installed separately. The project is actively maintained with recent releases, and wheels are provided for multiple Python versions and platforms (macOS, Linux, Windows, including aarch64).
OpenSlide C library (≥3.4.0) must be installed separately; installation method varies by platform.
License in practice
Licensed under LGPL-2.1-only with additional BSD-3-Clause, MIT, and public domain components. The copyleft LGPL treatment means derivative works must be licensed compatibly, though linking from a proprietary application is generally permitted if OpenSlide is dynamically linked.
Quickstart
pip install openslide-python
from openslide import OpenSlide
slide = OpenSlide('path/to/slide.svs')
region = slide.read_region((x, y), level, (width, height))Verify before relying
- Whether the OpenSlide C library (≥3.4.0) is pre-installed on target systems or must be managed separately in deployment
- Performance characteristics and memory efficiency when handling specific gigabyte-scale slide formats in production
- Recommended installation method for the separate OpenSlide C library dependency on different platforms
Package facts
| License | LGPL-2.1-only AND BSD-3-Clause AND MIT AND LicenseRef-Public-Domain copyleft |
| Python support | Supports the current Python release >=3.10 |
| Install friction | Medium. Platform-specific wheel |
| Runtime dependencies | 1 packagePillow |
| Maintenance | Actively maintained 67 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 270,441 / month, #8,236 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableIntended Audience :: DevelopersIntended Audience :: Healthcare IndustryIntended Audience :: Science/ResearchOperating System :: MacOS :: MacOS XOperating System :: Microsoft :: WindowsOperating System :: POSIX :: LinuxProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: Free Threading :: 2 - BetaTopic :: Scientific/Engineering :: Bio-InformaticsTyping :: Typed |
Evidence: openslide_python-1.4.6-cp310-cp310-macosx_10_9_universal2.whl; openslide_python-1.4.6-cp310-cp310-manylinux1_x86_64.manylinux_2_5_x86_64.whl; openslide_python-1.4.6-cp310-cp310-manylinux2014_aarch64.manylinux_2_17_aarch64.whl; openslide_python-1.4.6-cp310-cp310-win_amd64.whl; openslide_python-1.4.6-cp311-abi3-macosx_10_9_universal2.whl; openslide_python-1.4.6-cp311-abi3-manylinux1_x86_64.manylinux_2_5_x86_64.whl; openslide_python-1.4.6-cp311-abi3-manylinux2014_aarch64.manylinux_2_17_aarch64.whl; openslide_python-1.4.6-cp311-abi3-win_amd64.whl; openslide_python-1.4.6-cp313-cp313t-macosx_10_13_universal2.whl; openslide_python-1.4.6-cp313-cp313t-manylinux1_x86_64.manylinux_2_5_x86_64.whl; openslide_python-1.4.6-cp313-cp313t-manylinux2014_aarch64.manylinux_2_17_aarch64.whl; openslide_python-1.4.6-cp313-cp313t-win_amd64.whl; openslide_python-1.4.6-cp314-cp314t-macosx_10_15_universal2.whl; openslide_python-1.4.6-cp314-cp314t-manylinux1_x86_64.manylinux_2_5_x86_64.whl; openslide_python-1.4.6-cp314-cp314t-manylinux2014_aarch64.manylinux_2_17_aarch64.whl; openslide_python-1.4.6-cp314-cp314t-win_amd64.whl
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See also openslide-bin · large-image · dicomweb-client · tifffile · highdicom · OpenImageIO · python-gdcm · aspose-slides · ExifRead · PIMS