Source: Astryx

A React design system from Meta, released as open source.
Licence: MIT, copyright 2026 Meta Platforms.
The project calls itself beta. Its npm page shows the current version.
Built on React 19 or later (a hard requirement) and StyleX. You import CSS that's already built, so you don't have to adopt StyleX.
Packaging, as npm packages:
- @astryxdesign/core: the components, themes and utilities;
- @astryxdesign/cli: docs lookup, templates, scaffolding, themes and code changes;
- theme packages such as @astryxdesign/theme-neutral;
- @astryxdesign/richtext: a rich text editor and viewer.
150+ components, seven themes, dark mode, page templates, a CLI and an MCP server.
Docs at astryx.atmeta.com, plus a Storybook and a sandbox.
Its README says it grew inside Meta over eight years and powers 13,000+ apps there.

npm install @astryxdesign/core @astryxdesign/theme-neutral @stylexjs/stylex, plus the CLI as a dev dependency.
Import three stylesheets in order: reset.css, astryx.css, the theme's theme.css. Then wrap the app in a theme.
Recipes exist for Next.js (with or without Tailwind or StyleX) and Vite.
With no bundler, load it from esm.sh through an import map. npx @astryxdesign/cli template --cdn writes a starter page.

It's in beta.
Charts and the native (iOS, Android, macOS, Windows) packages are experimental and published only as canary builds.
The experimental lab package: the README says it isn't published; its package file says it is, as canary.
packages/README.md lists different themes from the main README. It looks out of date.
Always use the scoped CLI name. The bare astryx package on npm is unrelated.
Its layered pop-ups need recent browsers (CSS anchor positioning, Baseline 2026). In older supported browsers, pop-ups open but aren't positioned.
With server rendering, runtime themes flash on load. Use built themes.
Themes name a font but don't load it.
The README calls all components accessible. The contributing guide says automated checks cover only part of it, and keyboard, focus and screen-reader behaviour need checking by hand.
Its claims about use inside Meta come from the README, with no evidence shown.
Nothing was installed or run when it was read. Our build did try it: see Tool: Astryx theming.

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