# evanw/thumbhash

A very compact representation of an image placeholder

Repository: https://github.com/evanw/thumbhash
Canonical: https://ross.abutalabs.com/products/thumbhash
Homepage: https://evanw.github.io/thumbhash/
Language: Swift
License: MIT
License Family: permissive
Last push: 2024-05-26T10:17:57+00:00

## Health v2 (maintenance only)
Score: 30/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 35, longevity 90
- inputs: {"age_days": 1260, "days_push": 829, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4197, forks 91 (observed 2026-08-28T04:08:38.878787+00:00)

## What it is
ThumbHash is a compact encoding of an image placeholder that can be stored inline with data and rendered while the real image loads. It is a BlurHash alternative with more detail, aspect ratio, accurate colors, and alpha support, with implementations in JavaScript, Rust, Swift, and Java.

## Use cases
- generate tiny image placeholders for smoother lazy loading
- store compact image previews inline in a database
- show blurred placeholders while images load in a feed
- encode image aspect ratio and colors in a few bytes
- replace BlurHash with better color accuracy and alpha support

## When to choose
- you need compact image placeholders with alpha and aspect ratio support
- you want more detail and accurate colors than BlurHash in similar space
- you work in JavaScript, Rust, Swift, or Java

## When to avoid
- you need configurable encoding parameters
- you need a full-featured image format rather than a placeholder
- you rely on the broader BlurHash ecosystem

## Facets
- artifact type: library
- maturity: stable
- function: image-processing, serialization
- domain: image-processing, web-development, frontend
- platform: cross-platform, rust, jvm
- tags: image-placeholder, blurhash-alternative, lazy-loading, thumbhash, javascript, swift

## Member repositories
- evanw/thumbhash (main) score 30

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:38.878787+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 2026-08-29T18:22:34.085597+00:00, confidence not recorded.
  - readme: https://github.com/evanw/thumbhash (fetched 2026-08-28T04:08:38.878787+00:00, sha 4bb4488718d7)
  - homepage: https://evanw.github.io/thumbhash/ (fetched 2026-08-29T09:12:51.434960+00:00, sha 7773eb524eb1)
- Data as of 2026-08-30T08:39:29.467469+00:00.