# filamentgroup/criticalCSS

Finds the Above the Fold CSS for your page, and outputs it into a file

Repository: https://github.com/filamentgroup/criticalCSS
Canonical: https://ross.abutalabs.com/products/criticalcss
Language: JavaScript
License: MIT
License Family: permissive
Archived: true
Last push: 2022-10-20T20:56:41+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": 4452, "days_push": 1413, "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 1692, forks 72 (observed 2026-08-28T04:05:22.769979+00:00)

## What it is
CriticalCSS is a Node.js library that identifies the above-the-fold CSS for a given page or file and writes it to a file for inlining. It is archived and no longer maintained.

## Use cases
- extract critical css for a page
- inline above the fold styles to speed up page load
- generate critical css from a css file and url
- find which css rules apply above the fold

## When to avoid
- starting a new project - the repo is archived and unmaintained
- you need modern browser support or active maintenance - consider alternatives like critical or penthouse

## Facets
- artifact type: library
- maturity: abandoned
- function: css-framework, build-tool, developer-tools
- domain: web-development, frontend, performance
- platform: cli
- tags: critical-css, above-the-fold, phantomjs, page-speed, archived, nodejs

## Member repositories
- filamentgroup/criticalCSS (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:22.769979+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 2026-08-30T03:38:13.625070+00:00, confidence not recorded.
  - readme: https://github.com/filamentgroup/criticalCSS (fetched 2026-08-28T04:05:22.769979+00:00, sha 76c6dabd06be)
  - registry_npm: https://registry.npmjs.org/criticalcss (fetched 2026-08-29T11:13:24.062222+00:00, sha ef84cd832f9b)
- Data as of 2026-08-30T08:39:29.467469+00:00.