# zlib-ng/zlib-ng

zlib replacement with optimizations for "next generation" systems.

Repository: https://github.com/zlib-ng/zlib-ng
Canonical: https://ross.abutalabs.com/products/zlib-ng
Language: C
License: Zlib
License Family: permissive
Topics: compression, library, deflate, inflate, zlib, c, optimized, zlib-replacement, zlib-ng, zlib-license
Last push: 2026-08-26T12:32:03+00:00

## Health v2 (maintenance only)
Score: 84/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 57, longevity 100
- inputs: {"age_days": 4342, "days_push": 7, "days_rel": 211, "gap_med": 63, "n_releases_24m": 8}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2083, forks 342 (observed 2026-08-28T04:06:11.761739+00:00)

## What it is
A zlib-compatible data compression library rewritten in modern C11 with SIMD/CPU-intrinsic optimizations for deflate and inflate. It serves as a drop-in replacement for stock zlib, offering significantly faster compression on modern CPUs.

## Use cases
- speed up gzip/deflate compression in my application
- drop-in replacement for zlib with better performance
- fast inflate/decompression library in C
- compression library using AVX2/NEON intrinsics
- replace zlib without changing my code's API calls

## When to choose
- you need zlib API compatibility but want major speed gains on modern x86-64 or ARM CPUs
- you want a maintained, fuzz-tested zlib fork with clean modern C code
- your workload is compression-heavy and CPU-bound

## When to avoid
- you need exact byte-for-byte output identical to stock zlib in all cases
- you target very old CPUs without SIMD support where gains are minimal
- you need compression formats beyond zlib/deflate/gzip

## Facets
- artifact type: library
- maturity: active
- function: compression
- domain: developer-tools, performance, files
- platform: cross-platform, cpp, c
- tags: zlib, deflate, inflate, simd-optimization, drop-in-replacement, c11

## Member repositories
- zlib-ng/zlib-ng (main) score 84

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:11.761739+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:55:54.335621+00:00, confidence not recorded.
  - readme: https://github.com/zlib-ng/zlib-ng (fetched 2026-08-28T04:06:11.761739+00:00, sha b5c8f7efd7f5)
- Data as of 2026-08-30T08:39:29.467469+00:00.