# yahoo/blink-diff

A lightweight image comparison tool.

Repository: https://github.com/yahoo/blink-diff
Canonical: https://ross.abutalabs.com/products/blink-diff
Homepage: http://yahoo.github.io/blink-diff/
Language: JavaScript
License: MIT
License Family: permissive
Archived: true
Last push: 2020-02-14T10:25:30+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 4321, "days_push": 2392, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1204, forks 90 (observed 2026-08-28T04:03:59.025282+00:00)

## What it is
Blink-Diff is a lightweight JavaScript image comparison tool by Yahoo, usable both as a command-line utility and as an npm library. It compares PNG images pixel-by-pixel with configurable thresholds, perceptual comparison, cropping, and block-out regions, producing a highlighted difference image.

## Use cases
- compare two png images and highlight differences
- visual regression testing of screenshots
- detect pixel differences between ui screenshots
- generate a diff image showing what changed between two images
- compare website screenshots in automated tests
- ignore small pixel differences when comparing images

## When to choose
- you need a simple npm-based PNG diff tool for visual regression tests
- you want both a CLI and a programmatic JavaScript API
- you need threshold-based or perceptual image comparison with block-out regions

## When to avoid
- you need to compare formats other than PNG
- you need an actively maintained tool - the last release was in 2020
- you need advanced perceptual hashing or large-scale image comparison pipelines

## Facets
- artifact type: cli-tool
- maturity: maintenance
- function: image-processing, testing, cli
- domain: image-processing, testing, developer-tools
- platform: cli, cross-platform
- tags: image-diff, visual-regression, png, screenshot-comparison, perceptual-diff, nodejs

## Member repositories
- yahoo/blink-diff (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:59.025282+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 2026-08-30T06:19:41.495684+00:00, confidence not recorded.
  - readme: https://github.com/yahoo/blink-diff (fetched 2026-08-28T04:03:59.025282+00:00, sha 6bf4089f646e)
  - homepage: http://yahoo.github.io/blink-diff/ (fetched 2026-08-29T12:27:34.749099+00:00, sha 0abc6527a51e)
  - registry_npm: https://registry.npmjs.org/blink-diff (fetched 2026-08-29T12:27:34.758446+00:00, sha 7d25013b62af)
- Data as of 2026-08-30T08:39:29.467469+00:00.