# tukaani-project/xz

XZ Utils

Repository: https://github.com/tukaani-project/xz
Canonical: https://ross.abutalabs.com/products/xz
Homepage: https://tukaani.org/xz/
Language: C
License: NOASSERTION
License Family: other
Topics: c, cli, compression, library
Last push: 2026-08-22T14:40:02+00:00

## Health v2 (maintenance only)
Score: 83/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 99, release rhythm 53, longevity 100
- inputs: {"age_days": 1415, "days_push": 11, "days_rel": 155, "gap_med": 104, "n_releases_24m": 6}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1639, forks 259 (observed 2026-08-28T04:05:15.165986+00:00)

## What it is
XZ Utils is a complete C99 implementation of the .xz file format, consisting of the liblzma compression library (with a zlib-like API) and command-line tools such as xz, xzdec, xzgrep, and xzdiff. It uses LZMA2 as its primary filter, supports filter chaining and multithreaded compression, and typically achieves about 30% smaller files than gzip.

## Use cases
- compress files with better ratio than gzip
- decompress .xz archives from the command line
- embed a zlib-like compression API in a C application
- compress software packages for distribution
- compress executable files with BCJ filters
- grep or diff compressed files without manual decompression

## When to choose
- you need high compression ratios with fast decompression
- you distribute files that will be decompressed many times
- you want a zlib-style C API for the .xz format
- you need a standard, widely available compression tool on POSIX systems

## When to avoid
- you need multithreaded decompression (not yet supported)
- you need extremely fast compression where gzip or zstd is sufficient
- you need very low RAM usage at maximum compression settings
- you need cross-language bindings beyond C without extra work

## Facets
- artifact type: library
- maturity: stable
- function: compression, cli, file-system
- domain: developer-tools, files
- platform: windows, cross-platform, cli, c
- tags: lzma, xz-format, liblzma, data-compression, c99, command-line, linux, macos

## Member repositories
- tukaani-project/xz (main) score 83

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:15.165986+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 2026-08-30T03:46:31.787106+00:00, confidence not recorded.
  - readme: https://github.com/tukaani-project/xz (fetched 2026-08-28T04:05:15.165986+00:00, sha 03ab64ec34aa)
  - homepage: https://tukaani.org/xz/ (fetched 2026-08-29T11:19:37.804288+00:00, sha 32051505a06b)
  - site_page: https://tukaani.org/xz/liblzma-api/files.html (fetched 2026-08-29T11:19:37.813809+00:00, sha 1ab707b24cfe)
  - site_page: https://tukaani.org/xz/old.html (fetched 2026-08-29T11:19:37.815625+00:00, sha f488e02456ac)
- Data as of 2026-08-30T08:39:29.467469+00:00.