a2ui-oat: Framework-free web renderer with 37 components (v0.9)

[MisterTK]

Hey everyone! Sharing a2ui-oat, a lightweight A2UI renderer for the web that requires zero frameworks and zero build tooling.

Why I built this

Every web renderer in the ecosystem today targets a framework (React, Angular, Lit). I wanted something I could drop into any page with a CDN include — no bundler, no node_modules, no React. Just A2UI JSON in, semantic HTML out, styled automatically by Oat CSS.

What it does

• 37 catalog components — all 16 basic catalog components plus 21 extensions (tables, pagination, progress, meter, skeleton loaders, toasts, tooltips, alerts, breadcrumbs, sidebars, accordions, video, audio, and more)
• 22 registered client-side functions — data fetching (fetchPage, fetchAndAppend, subscribeSSE, subscribeWebSocket), navigation, formatting, validation, and logic operations
• ~13KB total client footprint (minified + gzipped)
• Custom catalog with theme support (7 CSS custom properties)
• @a2ui/web-lib integration via a single registerWithWebLib() call
• Dual-mode architecture — A2UI Mode for untrusted agents (catalog-constrained, schema-validated) and Direct Mode for trusted agents (emit semantic HTML, Oat styles it)
• Catalog validation — npm run validate checks spec compliance, renderer coverage, and function cross-references (16/16 passing)

Try it

Live demo: https://mistertk.github.io/a2ui-oat/

Install:

npm install a2ui-oat

CDN:

<script type="module">
  import { createOatRenderer } from "https://unpkg.com/a2ui-oat/renderer/index.js";
  const { renderer, functions } = createOatRenderer();
</script>

Links

• GitHub: https://github.com/MisterTK/a2ui-oat
• npm: https://www.npmjs.com/package/a2ui-oat
• Architecture doc: https://github.com/MisterTK/a2ui-oat/blob/main/docs/architecture.md
• Registry PR: Add a2ui-oat: framework-free web renderer (v0.9) #1032

Spec version: v0.9 only. License: MIT.

Would love feedback from anyone working on renderers or agent UIs!