# facebook/zstd

Zstandard - Fast real-time compression algorithm

Repository: https://github.com/facebook/zstd
Canonical: https://ross.abutalabs.com/products/zstd
Homepage: http://www.zstd.net
Language: C
License: NOASSERTION
License Family: other
Last push: 2026-08-23T07:06:41+00:00

## Health v2 (maintenance only)
Score: 67/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 8, longevity 100
- inputs: {"age_days": 4240, "days_push": 10, "days_rel": 560, "gap_med": null, "n_releases_24m": 1}
- 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 27628, forks 2566 (observed 2026-08-28T04:11:47.920362+00:00)

## What it is
Zstandard (zstd) is a fast lossless compression algorithm and its reference C library, offering zlib-level or better compression ratios at real-time speeds with a very fast decoder. It ships as a dual BSD/GPLv2-licensed library plus a command-line utility that produces and decodes .zst, .gz, .xz, and .lz4 files, with the format stabilized as RFC 8878.

## Use cases
- compress files in real time with better ratios than zlib
- compress data faster than zlib at similar or better ratios
- decompress .zst archives from the command line
- compress many small files efficiently with dictionary compression
- embed a fast lossless compressor in a C or C++ application
- convert between .zst, .gz, .xz, and .lz4 compressed files
- reduce storage and bandwidth for logs, databases, or backups
- tune the speed/compression trade-off from fast modes to high ratios

## When to choose
- you need real-time compression with zlib-level or better ratios
- decompression speed matters, e.g. for serving or streaming compressed data
- you compress many small payloads and can use dictionary compression
- you want a stable, standardized format (RFC 8878) with multiple independent implementations
- you need a battle-tested C library with bindings for other languages

## When to avoid
- you need maximum compression ratio regardless of speed, where xz/zpaq-style tools fit better
- you need the absolute fastest decompression only, where lz4 is faster
- you need archival features like solid archives or encryption, where 7-Zip or tar-based toolchains fit better
- your platform only supports a legacy codec and you cannot add a zstd dependency

## Facets
- artifact type: library
- maturity: stable
- function: compression, cli, developer-tools
- domain: developer-tools, files, performance
- platform: cross-platform, cli, c, windows, bsd
- tags: lossless-compression, zstd, dictionary-compression, real-time-compression, rfc8878, data-compression, c-library, bindings, command-line, linux, macos

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

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:11:47.920362+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 2026-08-29T16:54:30.723224+00:00, confidence not recorded.
  - readme: https://github.com/facebook/zstd (fetched 2026-08-28T04:11:47.920362+00:00, sha 4e437b90afcd)
  - homepage: http://www.zstd.net (fetched 2026-08-29T07:51:26.131235+00:00, sha abc5fed12e78)
- Data as of 2026-08-30T08:39:29.467469+00:00.