blosc
Blosc data compressor
What it is and what it does
Blosc is a Python wrapper around the Blosc C library, a high-performance compressor designed to move data to the processor cache faster than uncompressed memory access. It excels at compressing binary data with low entropy—sparse arrays, time series, regularly-spaced grids—and supports multiple compression codecs (blosclz, lz4, lz4hc, zlib, zstd, and optionally snappy). The package provides straightforward Python functions for compression and decompression, with control over compression level, codec selection, and shuffle modes (shuffle and bitshuffle).
The package is production-stable and widely used in scientific and data-processing workflows. It has no runtime Python dependencies and ships with prebuilt wheels for most platforms, though it does require a C compiler if building from source. The maintainers note that Python-Blosc2 is a more modern alternative with additional features, but this package remains actively maintained and suitable for straightforward compression tasks.
Use it for:
- Compress large numerical arrays in memory before storage or transmission to reduce I/O overhead.
- Speed up serialization of sparse matrices and time-series data in scientific computing pipelines.
- Reduce memory footprint of low-entropy datasets in data analysis and machine learning workflows.
- Accelerate data movement in HPC and distributed computing by compressing between cache and main memory.
- Archive and transmit gridded or regularly-spaced geospatial or climate data efficiently.
Worth the install?
AI-flagged interpretation of the facts on this page — verify before relying
Python wrapper for the Blosc compression library, providing fast compression and decompression of binary data optimized for numerical arrays and low-entropy data.
Yes, if you need fast compression of numerical or binary data. The package is stable, actively maintained, has no Python dependencies, and offers prebuilt wheels for common platforms. However, check whether Python-Blosc2 better suits your needs if you require more advanced features or plan a new project, as the maintainers recommend it as the more modern alternative.
Install
blosc on PyPI
pip
pip install bloscuv
uv add bloscpoetry
poetry add bloscInstalling blosc
Before you install
Medium install friction due to compiled C extension, but prebuilt wheels are available for common platforms (Windows, macOS, Linux on x86_64 and ARM64). Package is actively maintained with recent releases.
License in practice
BSD-3-Clause permissive license allows commercial and private use with minimal restrictions; attribution required.
Quickstart
pip install blosc
import blosc
compressed = blosc.compress(b'data_to_compress')
decompressed = blosc.decompress(compressed)
Requires Python 3.9 or higher; C extension compilation needed if wheels unavailable for your platform.
Verify before relying
- Whether the package is still recommended for new projects given the note about Python-Blosc2 being more modern and actively maintained.
- Performance characteristics and codec availability in the current 1.11.4 release compared to the benchmarked 1.5.1 version shown in documentation.
Package facts
| License | https://opensource.org/licenses/BSD-3-Clause (permissive) |
| Python support | supports the current Python release (>=3.9) |
| Install friction | medium — platform-specific wheel |
| Runtime dependencies | none |
| Maintenance | actively maintained — 209 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 608,604/month — #5,779 on PyPI (30-day window, as of 2026-08-14) |
| Known vulnerabilities | none known (OSV.dev, checked 2026-08-14) |
Evidence: blosc-1.11.4-cp310-cp310-macosx_10_9_x86_64.whl; blosc-1.11.4-cp310-cp310-macosx_11_0_arm64.whl; blosc-1.11.4-cp310-cp310-manylinux2014_aarch64.manylinux_2_17_aarch64.manylinux_2_28_aarch64.whl; blosc-1.11.4-cp310-cp310-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl; blosc-1.11.4-cp310-cp310-musllinux_1_2_aarch64.whl; blosc-1.11.4-cp310-cp310-musllinux_1_2_x86_64.whl; blosc-1.11.4-cp310-cp310-win32.whl; blosc-1.11.4-cp310-cp310-win_amd64.whl; blosc-1.11.4-cp311-cp311-macosx_10_9_x86_64.whl; blosc-1.11.4-cp311-cp311-macosx_11_0_arm64.whl; blosc-1.11.4-cp311-cp311-manylinux2014_aarch64.manylinux_2_17_aarch64.manylinux_2_28_aarch64.whl; blosc-1.11.4-cp311-cp311-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl; blosc-1.11.4-cp311-cp311-musllinux_1_2_aarch64.whl; blosc-1.11.4-cp311-cp311-musllinux_1_2_x86_64.whl; blosc-1.11.4-cp311-cp311-win32.whl; blosc-1.11.4-cp311-cp311-win_amd64.whl; blosc-1.11.4-cp312-cp312-macosx_10_13_x86_64.whl; blosc-1.11.4-cp312-cp312-macosx_11_0_arm64.whl; blosc-1.11.4-cp312-cp312-manylinux2014_aarch64.manylinux_2_17_aarch64.manylinux_2_28_aarch64.whl; blosc-1.11.4-cp312-cp312-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl
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