---
id: blosc
version: "1.11.4"
license: https://opensource.org/licenses/BSD-3-Clause
license_treatment: permissive
maintenance: active
---

# blosc — Blosc data compressor

License: permissive · Maintenance: active · Downloads: 608.6K/mo

## 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 above — 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

pip install blosc
uv add blosc
poetry add blosc

## Installing 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_current
- Install friction: medium
- Maintenance: active
- Downloads: 608.6K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

blosc compression python, fast binary data compression, numerical array compression, blosc wrapper, high-performance data compression, sparse data compression, time series compression, compression, numerical-data, c-extension

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