Open UI · Index

Open UI

W3C Community Group research and specs for native, styleable HTML controls

Tier A · StrongReferenceDesign System DocsPrimitiveopen-ui.org

Open UI is the W3C Community Group that documents how UI controls actually behave across design systems, then turns that research into proposals for the web platform itself. It publishes 61 component documents — 31 'research' pages that compare anatomy, states, and terminology across a dozen real design systems, and 24 'explainer' pages that specify proposed platform features. Its graduated work is already shipping in browsers: the Popover API, Invoker Commands, and customizable `<select>` all came through here, with Combobox, Menu elements, Toolbar, Navigation Bar, and Focusgroup still in flight. It is the source of truth for what a component *is* before anyone writes a line of framework code.

For an agent

Check here BEFORE you install a headless primitive — if the control you need is a popover, a dialog, an invoker, or a customizable select, the platform may already do it and Open UI's explainer tells you the exact attribute surface and browser support. The `.research` pages are the best machine-readable answer to 'what should I call this part?' because they tabulate real slot and part names across Carbon, Material, Fluent, and friends, which is exactly what you want when naming props for a new component. Two traps: an explainer is a proposal, not a shipped feature, so always confirm graduation status before generating code from one, and the repo carries a W3C contributor agreement rather than a normal OSS licence, so do not copy prose wholesale.

Why it is here. It is the only entry in this index that shapes the browser itself, and the reason 'just use the native element' is now a defensible answer for popovers, dialogs, and selects. Its cross-system component matrix is a naming authority nothing else matches.

Install command, framework, licence and component list.

Facts

License: Unknown
Pricing: Free, Open source
Framework: Vanilla JS, Web Components
Styling: Vanilla CSS
Distribution: GitHub repository, Article, thread, or post
Platform: Web
Content type: Prose / writing, Code
Agent readiness: Structured documentation, Readable open source
Accessibility: Semantic HTML, Full ARIA pattern implemented, Keyboard navigable, Focus management and visible focus
Maturity: Actively maintained
GitHub stars: 4,512

Components it ships

61 total

Notable for

W3C Community Group, standards track
Popover API and customizable select originated here
cross-design-system component name matrix
31 research pages plus 24 explainers
4.5k GitHub stars, active in 2026

Provenance

Verified 2026-08-16. HTTP 200. https://open-ui.org (full HTML fetched and link-extracted; /components/ and /research/ index paths return 404, individual /components/*.research and *.explainer pages are the real structure), https://api.github.com/repos/openui/open-ui via gh

Also in Design Systems & Brand Guidelines

open-ui.orgTier A