# react-cosmos/react-cosmos

Sandbox for developing and testing UI components in isolation

Repository: https://github.com/react-cosmos/react-cosmos
Canonical: https://ross.abutalabs.com/products/react-cosmos
Homepage: https://reactcosmos.org
Language: TypeScript
License: MIT
License Family: permissive
Topics: react, devtools, ui, components, testing, sandbox
Last push: 2026-08-17T19:36:17+00:00

## Health v2 (maintenance only)
Score: 94/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 98, release rhythm 86, longevity 100
- inputs: {"age_days": 4592, "days_push": 16, "days_rel": 16, "gap_med": 44.5, "n_releases_24m": 9}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 8683, forks 384 (observed 2026-08-28T04:10:24.217571+00:00)

## What it is
React Cosmos is a sandbox for developing and testing React UI components in isolation, with a fixture-based file convention and a playground UI for browsing, previewing, and manipulating components. It integrates with Vite, Webpack, Next.js, and React Native, supports a full-stack plugin system, and can export an interactive component library to static hosting.

## Use cases
- develop react components in isolation
- browse and preview component states with fixtures
- test ui components with responsive viewports
- build an interactive component library for static hosting
- prototype react components quickly
- debug component props via a control panel
- extend a component workshop with plugins
- work with react native or next.js components in a sandbox

## When to choose
- you want a fast, lightweight Storybook alternative focused on isolated component development
- your project uses Vite, Webpack, Next.js, or React Native and needs a component playground
- you want file-system based fixtures to define component states
- you need a plugin system to customize the component development workflow

## When to avoid
- your primary goal is publishing polished design-system style guides or documentation sites
- you need deep ecosystem integrations, addons, or community size that Storybook offers
- you are not working with React or React Native

## Facets
- artifact type: application
- maturity: active
- function: ui-components, testing, developer-tools, cli, plugin-system, documentation
- domain: frontend, web-development, developer-tools, testing
- platform: cross-platform, cli
- tags: react, component-workshop, storybook-alternative, fixtures, component-explorer, vite, webpack, nextjs, react-native, static-export, nodejs, web-server

## Member repositories
- react-cosmos/react-cosmos (main) score 94

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:24.217571+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 2026-08-29T17:25:35.757929+00:00, confidence not recorded.
  - readme: https://github.com/react-cosmos/react-cosmos (fetched 2026-08-28T04:10:24.217571+00:00, sha 3caaf8edaa7d)
  - homepage: https://reactcosmos.org (fetched 2026-08-29T08:26:20.414485+00:00, sha 9ae46622c53f)
  - site_page: https://reactcosmos.org/docs (fetched 2026-08-29T08:26:20.423436+00:00, sha 19a90abc9531)
  - site_page: https://reactcosmos.org/about (fetched 2026-08-29T08:26:20.425497+00:00, sha 14105a2e2588)
  - site_page: https://reactcosmos.org/docs/getting-started (fetched 2026-08-29T08:26:20.427307+00:00, sha 36ee4ca12114)
  - site_page: https://reactcosmos.org/docs/user-interface (fetched 2026-08-29T08:26:20.429726+00:00, sha 981ae9fcb2dc)
  - site_page: https://reactcosmos.org/docs/getting-started/vite (fetched 2026-08-29T08:26:20.431390+00:00, sha b29014f4ea24)
  - site_page: https://reactcosmos.org/docs/getting-started/webpack (fetched 2026-08-29T08:26:20.433058+00:00, sha cbff85022d41)
  - site_page: https://reactcosmos.org/docs/getting-started/react-native (fetched 2026-08-29T08:26:20.434740+00:00, sha a2ad1c09bd34)
  - site_page: https://reactcosmos.org/docs/getting-started/next (fetched 2026-08-29T08:26:20.436557+00:00, sha 1eaeb9e53c98)
- Data as of 2026-08-30T08:39:29.467469+00:00.