# google/guetzli

Perceptual JPEG encoder

Repository: https://github.com/google/guetzli
Canonical: https://ross.abutalabs.com/products/guetzli
Language: C++
License: Apache-2.0
License Family: permissive
Topics: jpeg-encoder
Archived: true
Last push: 2023-04-22T19:41:10+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 3603, "days_push": 1229, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 12913, forks 995 (observed 2026-08-28T04:11:00.136931+00:00)

## What it is
Guetzli is a perceptual JPEG encoder from Google that produces images 20-30% smaller than libjpeg at equivalent visual quality. It is a C++ command-line tool that generates sequential (nonprogressive) JPEGs.

## Use cases
- compress jpeg images to smaller file sizes without visible quality loss
- optimize images for faster web page loading
- batch re-encode photos at high visual quality
- reduce bandwidth for image-heavy websites
- compare jpeg encoders for compression density

## When to choose
- you need maximum jpeg compression at high visual quality and can tolerate slow encoding
- you are optimizing static image assets for the web
- you want a free, open-source offline image compressor

## When to avoid
- you need fast or real-time encoding - guetzli is very slow
- you need progressive JPEG output
- you want an actively developed tool with recent improvements
- you need to encode formats other than JPEG input (e.g., PNG output)

## Facets
- artifact type: cli-tool
- maturity: maintenance
- function: image-processing, compression
- domain: image-processing, graphics, web-development
- platform: windows, cli, cross-platform
- tags: jpeg-encoder, perceptual-compression, image-optimization, c-plus-plus, linux, macos

## Member repositories
- google/guetzli (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:11:00.136931+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 2026-08-29T17:13:41.567667+00:00, confidence not recorded.
  - readme: https://github.com/google/guetzli (fetched 2026-08-28T04:11:00.136931+00:00, sha b1260eefac39)
- Data as of 2026-08-30T08:39:29.467469+00:00.