# cosscom/coss

coss.com/ui is the official design system of Cal.com

Repository: https://github.com/cosscom/coss
Canonical: https://ross.abutalabs.com/products/coss
Homepage: https://coss.com
Language: TypeScript
License: AGPL-3.0
License Family: copyleft
Topics: nextjs, radix-ui, react, tailwindcss, shadcn, shadcn-ui, tanstack-table, base-ui
Last push: 2026-08-19T07:38:34+00:00

## Health v2 (maintenance only)
Score: 66/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 98, release rhythm 35, longevity 49
- inputs: {"age_days": 687, "days_push": 14, "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 10479, forks 531 (observed 2026-08-28T04:10:42.074779+00:00)

## What it is
coss.com/ui (formerly Origin UI) is the official design system of Cal.com, a collection of accessible, composable React UI components built on top of Base UI and styled with Tailwind CSS. Following the shadcn/ui copy-paste ethos, components are added to your codebase via CLI so you own the source code.

## Use cases
- add accessible react components to my app
- shadcn/ui alternative built on base ui
- copy-paste ui components for nextjs
- design system for react with tailwind
- migrate from radix ui components
- find a date picker or combobox component for react
- ui component library built for developers and ai

## When to choose
- you want shadcn/ui-style copy-paste components with Base UI primitives underneath
- you're building a React/Next.js app with Tailwind CSS and want accessible, well-designed components
- you want to own and customize component source code rather than depend on a package
- you're contributing to or aligning with the Cal.com design ecosystem

## Facets
- artifact type: library
- maturity: experimental
- function: ui-components, frontend-framework, theme, accessibility
- domain: web-development, frontend, web-design, developer-tools
- platform: -
- tags: shadcn-ui, base-ui, tailwindcss, radix-ui, design-system, copy-paste-components, cal-com, nextjs, tanstack-table, component-library, react, typescript, nodejs, web-server

## Member repositories
- cosscom/coss (main) score 66

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:42.074779+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 2026-08-29T17:18:58.663514+00:00, confidence not recorded.
  - readme: https://github.com/cosscom/coss (fetched 2026-08-28T04:10:42.074779+00:00, sha 7db4cf3f4ca9)
  - homepage: https://coss.com (fetched 2026-08-29T08:18:25.426127+00:00, sha c82309e1afc1)
  - site_page: https://coss.com/ui/docs (fetched 2026-08-29T08:18:25.435515+00:00, sha 5e5ad76c99b3)
  - site_page: https://coss.com/ui/docs/components/accordion (fetched 2026-08-29T08:18:25.437479+00:00, sha c6d348d4f281)
  - site_page: https://coss.com/ui/docs/components/alert (fetched 2026-08-29T08:18:25.439340+00:00, sha 249f5ffe1403)
  - site_page: https://coss.com/ui/docs/components/alert-dialog (fetched 2026-08-29T08:18:25.440992+00:00, sha ce857470b902)
  - site_page: https://coss.com/ui/docs/components/autocomplete (fetched 2026-08-29T08:18:25.442771+00:00, sha 9e84c0636d37)
  - site_page: https://coss.com/ui/docs/components/avatar (fetched 2026-08-29T08:18:25.444731+00:00, sha 554fe98f0ae1)
  - site_page: https://coss.com/ui/docs/components/badge (fetched 2026-08-29T08:18:25.446602+00:00, sha 688a612d75f8)
  - site_page: https://coss.com/ui/docs/components/breadcrumb (fetched 2026-08-29T08:18:25.448291+00:00, sha 58408ef526ea)
- Data as of 2026-08-30T08:39:29.467469+00:00.