# unocss/unocss

The instant on-demand atomic CSS engine.

Repository: https://github.com/unocss/unocss
Canonical: https://ross.abutalabs.com/products/unocss
Homepage: https://unocss.dev
Language: TypeScript
License: NOASSERTION
License Family: other
Topics: atomic-css, vite-plugin, windicss, engine, unocss
Last push: 2026-08-26T12:41:34+00:00

## Health v2 (maintenance only)
Score: 95/100 (v2, computed 2026-09-03T02:39:23.370411+00:00)
- activity 99, release rhythm 86, longevity 100
- inputs: {"age_days": 1798, "days_push": 7, "days_rel": 12, "gap_med": 5.5, "n_releases_24m": 67}
- 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 18942, forks 982 (observed 2026-08-28T04:11:27.256511+00:00)

## What it is
UnoCSS is an instant on-demand atomic CSS engine that generates utility CSS classes as they are used, with no core utilities - all functionality comes from composable presets. It integrates with Vite, Webpack, PostCSS, Nuxt, Astro, Next.js, Svelte, CLI, and offers a browser CDN runtime and developer inspector.

## Use cases
- generate utility-first css on demand instead of writing stylesheets
- tailwind css alternative with faster build times
- use atomic css classes in vite or webpack projects
- style web components with shadow-dom inline css
- use icons as css classes without an icon library
- group utilities in html attributes instead of class names
- add utility css to nuxt or astro apps

## When to choose
- you want a fast, fully customizable atomic CSS engine with preset-based utilities
- you are on Vite/Nuxt/Astro/Svelte and want first-class integration with HMR
- you need Tailwind-like utilities but with custom rules, shortcuts, and attributify mode
- you want a zero-dependency, browser-friendly runtime for prototypes via CDN

## When to avoid
- your team is already invested in Tailwind CSS and its ecosystem plugins
- you prefer semantic, component-scoped CSS over utility classes
- you need a webpack setup beyond global mode or rely on CommonJS-only tooling

## Facets
- artifact type: library
- maturity: active
- function: css-framework, build-tool, plugin-system
- domain: frontend, web-development, web-design, developer-tools
- platform: browser, cli, editor-plugin
- tags: atomic-css, utility-first, vite-plugin, tailwind-alternative, windicss, on-demand-css, attributify-mode, css-icons, nodejs, web-server

## Member repositories
- unocss/unocss (main) score 95

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:11:27.256511+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 2026-08-29T17:01:00.375557+00:00, confidence not recorded.
  - readme: https://github.com/unocss/unocss (fetched 2026-08-28T04:11:27.256511+00:00, sha e60f1bf1af77)
  - homepage: https://unocss.dev (fetched 2026-08-29T07:59:31.409169+00:00, sha 9c2583eaf6ed)
  - site_page: https://unocss.dev/integrations (fetched 2026-08-29T07:59:31.419384+00:00, sha 4e2165b99410)
  - site_page: https://unocss.dev/integrations/vite (fetched 2026-08-29T07:59:31.421265+00:00, sha 8b3ed02dc989)
  - site_page: https://unocss.dev/integrations/nuxt (fetched 2026-08-29T07:59:31.423572+00:00, sha 897dd0db6f08)
  - site_page: https://unocss.dev/integrations/next (fetched 2026-08-29T07:59:31.426173+00:00, sha 9068889b0fa2)
  - site_page: https://unocss.dev/integrations/astro (fetched 2026-08-29T07:59:31.428749+00:00, sha d87409b99c74)
  - site_page: https://unocss.dev/integrations/svelte-scoped (fetched 2026-08-29T07:59:31.430897+00:00, sha 7550abd8dd39)
  - site_page: https://unocss.dev/integrations/webpack (fetched 2026-08-29T07:59:31.432966+00:00, sha 9cb108a958d1)
  - site_page: https://unocss.dev/integrations/runtime (fetched 2026-08-29T07:59:31.434651+00:00, sha 5dd120bad0d8)
- Data as of 2026-08-30T08:39:29.467469+00:00.