astryx

Astryx is Meta's open source design system, grown inside Meta over eight years and powering 13,000+ apps. Built on React 19 and StyleX, it ships 150+ accessible components, brand-level theming, dark mode, templates, and a CLI. Components are openly composable, with swizzle to eject source; styling is not locked in, so Tailwind, CSS modules, or plain CSS can override via className; themes are CSS custom property overrides requiring no wrapping. API, docs, and CLI are co-designed so people and AI assistants build the same way. Currently in Beta.

• 150+ accessible React components
• StyleX-powered, no styling lock-in
• CSS variable theming and dark mode
• Swizzle to eject component source
• CLI and docs built for humans and AI