zlib-ng

library1.0.0pypypi✓ verified 85d ago

zlib-ng is a Python library that provides high-performance bindings for the zlib-ng compression library. It serves as a drop-in replacement for Python's standard `zlib` and `gzip` modules, offering significantly faster compression and decompression by utilizing optimized algorithms and CPU intrinsics. The library offers `zlib_ng`, `gzip_ng`, and `gzip_ng_threaded` modules. The current version, 1.0.0, emphasizes stability and performance. It generally aligns its development with the upstream zlib-ng C library, with updates primarily focusing on Python compatibility and performance enhancements.

serialization data

pip install zlib-ng

github ↗package ↗docs ↗

INSTALL

IMPORT

SIG · ZLIB-NG

zlib-ng

serializationpythonv1.0.0

Install

1.6s avg

Import

8ms

Disk

16MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v1.0.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.920 runs

installs and imports cleanly · install 0.0s · import 0.003s · 18.1MB

glibc

py 3.10–3.920 runs

installs and imports cleanly · install 1.6s · import 0.000s · 19MB

16MB installed

● package 16MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

zlib_ng

✓ from zlib_ng import zlib_ng

gzip_ng

✓ from zlib_ng import gzip_ng

gzip_ng_threaded

✓ from zlib_ng import gzip_ng_threaded

For multi-threaded streaming compression/decompression.

zlib

✓ import zlib_ng as zlib

✗ import zlib_ng

For drop-in replacement of the standard library's 'zlib' module, it's common to import 'zlib_ng' and alias it as 'zlib'.

gzip

✓ import gzip_ng as gzip

✗ import gzip_ng

For drop-in replacement of the standard library's 'gzip' module, it's common to import 'gzip_ng' and alias it as 'gzip'.

This quickstart demonstrates basic compression and decompression using the `zlib_ng` module, which mimics the standard `zlib` module's API. It compresses a byte string and then decompresses it, verifying that the original data is recovered.

from zlib_ng import zlib_ng original_data = b'This is some data that will be compressed using zlib-ng.' # Compress data compressed_data = zlib_ng.compress(original_data) print(f"Original size: {len(original_data)}") print(f"Compressed size: {len(compressed_data)}") # Decompress data decompressed_data = zlib_ng.decompress(compressed_data) print(f"Decompressed size: {len(decompressed_data)}") assert original_data == decompressed_data print("Data compressed and decompressed successfully!")

Debug

Known issues

gotchaCompression level 1 in `zlib_ng` offers worse compression rates compared to the standard `zlib` module. For most other compression levels (0 or 2-9), `zlib_ng` provides better compression.

fix

Avoid using compression level 1 if optimal compression ratio is critical. Use other levels (e.g., default -1, or 2-9) for improved performance and usually better compression.

affects: All versions

gotchaThe `gzip_ng.open()` function returns a `gzip_ng.GzipNGFile` object, not `gzip.GzipFile` as in the standard library. While `gzip_ng.GzipFile` exists as an alias for compatibility, be aware of the underlying type difference if performing type checks.

fix

If performing type checks, check for `gzip_ng.GzipNGFile` or rely on duck-typing due to API compatibility. Using `import gzip_ng as gzip` helps maintain consistent code behavior.

affects: All versions

gotchaPre-built wheels for `zlib-ng` are available for common platforms (Linux, Windows, MacOS). For less common or specific system architectures, installation might require building the C `zlib-ng` library from source, which necessitates appropriate build tools (like a C compiler) on the target system.

fix

Ensure that your deployment environment has the necessary build tools if pre-built wheels are not available for your specific platform/architecture.

affects: All versions

gotchaThe `gzip_ng_threaded.open()` function is designed exclusively for streaming operations. Seeking within files opened with `gzip_ng_threaded.open()` is not supported.

fix

For files requiring random access or seeking, use `gzip_ng.open()` instead of `gzip_ng_threaded.open()`.

affects: All versions

breakingVersion 1.0.0 of `zlib-ng` has dropped official support for Python 3.8 and 3.9.

fix

Ensure your project uses Python 3.10 or newer to be compatible with `zlib-ng` version 1.0.0. The `requires_python` metadata is `>=3.9` on PyPI, but documentation clarifies 3.8/3.9 are no longer supported as of 1.0.0.

affects: 1.0.0 and later

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'zlib_ng'

The 'zlib-ng' package, which provides the 'zlib_ng' module, is not installed in the current Python environment.

fix

Install the package using pip: `pip install zlib-ng`

Failed building wheel for zlib-ng

The compilation of the underlying C extension fails due to missing C compilers or necessary build tools (e.g., build-essential on Linux, Visual C++ build tools on Windows, or Xcode Command Line Tools on macOS).

fix

Install the required C/C++ compiler and development tools for your operating system. For example, on Debian/Ubuntu: `sudo apt-get install build-essential`

ImportError: cannot import name 'zlib_ng' from 'zlib'

The user is attempting to import the 'zlib_ng' module from Python's standard 'zlib' module, but 'zlib_ng' is a separate top-level module provided by the 'zlib-ng' package.

fix

Import 'zlib_ng' directly: `import zlib_ng`. To use it as a drop-in replacement for the standard 'zlib', use `import zlib_ng as zlib`.

Upgrade

Version history

1.0.0latest on PyPI · released Sep 10, 2025

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Dependencies

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Agent activity

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Resources

githubhttps://github.com/pycompression/python-zlib-ng ↗

packagehttps://pypi.org/project/zlib-ng/ ↗

docshttps://python-zlib-ng.readthedocs.io ↗