# facebook/openzl

A novel data compression framework

Repository: https://github.com/facebook/openzl
Canonical: https://ross.abutalabs.com/products/openzl
Homepage: https://openzl.org
Language: C
License: NOASSERTION
License Family: other
Last push: 2026-08-25T22:11:10+00:00

## Health v2 (maintenance only)
Score: 67/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 51, longevity 24
- inputs: {"age_days": 337, "days_push": 8, "days_rel": 118, "gap_med": 213, "n_releases_24m": 2}
- 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 3165, forks 162 (observed 2026-08-28T04:07:46.663946+00:00)

## What it is
OpenZL is a format-aware lossless data compression framework from Meta that builds specialized compressors from a description of your data format, composed as DAGs of codecs. It ships a core C library, a zli CLI, training tools, and a universal decompressor compatible with all generated compressors.

## Use cases
- compress large numeric arrays faster and smaller than zstd
- compress structured data like csv or json with format-aware parsing
- train a specialized compressor for my custom binary data format
- compress AI/ML training data at datacenter speeds
- build a custom compression pipeline from composable codecs
- benchmark compression tools on my own files

## When to choose
- you handle large volumes of specialized, structured, or numeric datasets and need both high ratios and high throughput
- you want one universal decompressor to read frames produced by many different specialized compressors
- you need production-grade compression used at Meta scale with forward-compatibility guarantees

## When to avoid
- you just need simple general-purpose compression of unstructured files with a mature ecosystem
- you need a frozen, stable API and compressed format - both are still evolving
- you rely on custom codecs, which break compatibility with the standard OpenZL decompressor

## Facets
- artifact type: library
- maturity: active
- function: compression, serialization, cli, developer-tools
- domain: files, developer-tools, performance
- platform: windows, cross-platform, cli, python, cpp, c
- tags: data-compression, format-aware-compression, lossless-compression, compression-graphs, universal-decompressor, zstd, sddl, training-tool, data-engineering, linux, macos

## Member repositories
- facebook/openzl (main) score 67

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:46.663946+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 2026-08-30T07:25:10.829962+00:00, confidence not recorded.
  - readme: https://github.com/facebook/openzl (fetched 2026-08-28T04:07:46.663946+00:00, sha bf4bacdc47f3)
  - homepage: https://openzl.org (fetched 2026-08-29T09:39:55.406620+00:00, sha 56fa8d92cc62)
  - site_page: https://openzl.org/getting-started/quick-start (fetched 2026-08-29T09:39:55.420019+00:00, sha 75863eed2791)
  - site_page: https://openzl.org/getting-started/introduction (fetched 2026-08-29T09:39:55.423056+00:00, sha 8bf6a773f606)
  - site_page: https://openzl.org/getting-started/concepts (fetched 2026-08-29T09:39:55.425860+00:00, sha 16abf64d77ca)
  - site_page: https://openzl.org/getting-started/using-openzl (fetched 2026-08-29T09:39:55.428142+00:00, sha dee194e0b26d)
  - site_page: https://openzl.org/getting-started/more-tools (fetched 2026-08-29T09:39:55.430643+00:00, sha f7029a3d06ac)
  - site_page: https://openzl.org/getting-started/examples/c/numeric-array (fetched 2026-08-29T09:39:55.433094+00:00, sha 4ec0bb196875)
  - site_page: https://openzl.org/getting-started/examples/c/benchmarking (fetched 2026-08-29T09:39:55.435518+00:00, sha 4b9ca76ba063)
  - site_page: https://openzl.org/getting-started/examples/c/custom-formats (fetched 2026-08-29T09:39:55.437595+00:00, sha d0986657c384)
- Data as of 2026-08-30T08:39:29.467469+00:00.