Astryx

Astryx (Meta, MIT) is an open-source web design system that powers 13,000+ of Meta’s internal applications — “fully customizable and built for how we build now — by people and the agents working alongside them.” It’s a founding source of this spoke (previously parked in the hub _inbox as a ui-frameworks stray).

What’s in it

A design system in the full sense — not just components but the layers beneath and around them:

• Foundations — typography, color, layout, and accessibility primitives (design tokens).
• 150+ accessible React components with TypeScript.
• Patterns — ready-made solutions for tables, forms, wizards, navigation.
• Theming — seven CSS-variable themes (neutral, butter, chocolate, matcha, stone, gothic, y2k); themes override CSS custom properties without forking.
• Built on React + StyleX, shipping pre-built CSS with no build plugins; styling isn’t locked to a framework (works with Tailwind, CSS modules, or plain CSS). Monorepo: @astryxdesign/core, @astryxdesign/cli.

Fully customizable + agent-ready

Two marketed axes. Customization is layered: themes swap CSS variables, components expose internal building blocks for composition, and styling stays framework-agnostic. Agent-ready means the API, docs, and CLI are deliberately predictable so humans and AI agents build identically — the clearest instance of the agent-ready-ui thread: a design system whose conventions are legible enough for a coding agent to compose reliably.

Tier / caveats

T2 — first-party repo/README, authoritative for structure; “fully customizable / agent-ready” are the project’s framing, not independent evaluation. It’s Meta’s internal system opened up, so real-world external adoption is unproven.

Related

meta · design-system · ui-framework · agent-ready-ui · opentui