Open Generative UI

Let agents generate fully interactive HTML/CSS/JS UIs that stream live into the chat.

"use client";/** * Open-Ended Generative UI — minimal setup. * * Enabling `openGenerativeUI` in the runtime (see * `src/app/api/copilotkit-ogui/route.ts`) streams agent-authored HTML + * CSS through the built-in `OpenGenerativeUIActivityRenderer`, mounted * inside a sandboxed iframe. * * Reference: https://docs.copilotkit.ai/generative-ui/open-generative-ui */import React from "react";import {  CopilotKit,  CopilotChat,  useConfigureSuggestions,} from "@copilotkit/react-core/v2";const VISUALIZATION_DESIGN_SKILL = `When generating UI with generateSandboxedUi, your goal is to produce a polished, intricate, EDUCATIONAL visualisation. Use inline SVG or canvas, CSS keyframe animations, clear labels and legends, and the semantic palette: indigo #6366f1 (accent), emerald #10b981 (success), amber #f59e0b (warning), rose #ef4444 (error), slate #64748b (neutral). Output initialHeight, 2-3 placeholderMessages, css, and html (single root container).`;const minimalSuggestions = [  {    title: "3D axis visualization (model airplane)",    message:      "Visualize pitch, yaw, and roll using a 3D model airplane. Render a simple airplane silhouette (SVG or CSS-3D) at the origin, with three labelled axes. Animate the airplane cycling through each rotation in turn with a legend.",  },  {    title: "How a neural network works",    message:      "Animate how a simple feed-forward neural network processes an input. Show 3 layers with connections whose thickness encodes weight magnitude. Animate activations pulsing forward input -> hidden -> output in a loop.",  },  {    title: "Quicksort visualization",    message:      "Visualize quicksort on an array of ~10 bars. Highlight the pivot in amber, compared elements in indigo, swapped in emerald; fade sorted elements to slate. Auto-advance through the sort.",  },];export default function OpenGenUiDemo() {  return (    <CopilotKit      runtimeUrl="/api/copilotkit-ogui"      agent="open-gen-ui"      openGenerativeUI={{ designSkill: VISUALIZATION_DESIGN_SKILL }}    >      <div className="flex justify-center items-center h-screen w-full">        <div className="h-full w-full max-w-4xl flex flex-col p-3">          <Chat />        </div>      </div>    </CopilotKit>  );}function Chat() {  useConfigureSuggestions({    suggestions: minimalSuggestions,    available: "always",  });  return <CopilotChat agentId="open-gen-ui" className="flex-1 rounded-2xl" />;}

What is this?#

Open Generative UI lets the agent generate complete, sandboxed UI on the fly (HTML, CSS, and JavaScript) and stream it live into the chat. The user sees the interface build in real time: styles apply first, then HTML streams in progressively, and finally JavaScript expressions execute one by one.

Free course: See this pattern built end-to-end in Build Interactive Agents with Generative UI — a free DeepLearning.AI short course taught by CopilotKit's CEO covering the full Generative UI spectrum (Controlled, Declarative, and Open-Ended).

Key benefits:

No predefined components — the agent creates any UI it needs, on demand
Live streaming — HTML streams into a preview as it's generated
CDN libraries — the generated UI can load Chart.js, D3, Three.js, etc. via <script> tags
Secure sandboxing — content runs in an isolated iframe without same-origin access
Sandbox functions — optionally expose host functions to the generated UI for two-way communication

Minimal setup#

Turning on Open Generative UI takes one flag in the runtime plus a plain <CopilotChat /> on the frontend; the built-in activity renderer is auto-registered by CopilotKit, so no extra wiring is needed.

Enable it in the runtime#

Add OpenGenerativeUIMiddleware to your runtime configuration:

route.ts

      runtime: new CopilotRuntime({        // @ts-ignore -- see main route.ts        agents,        openGenerativeUI: {          agents: ["open-gen-ui", "open-gen-ui-advanced"],        },      }),

The OpenGenerativeUIMiddleware then converts the agent's streamed generateSandboxedUi tool call into open-generative-ui activity events, which the built-in OpenGenerativeUIActivityRenderer mounts inside a sandboxed iframe.

Drop `<CopilotChat />` into the page#

Wrap your app in CopilotKit and render <CopilotChat> — no extra props needed:

page.tsx

  return (    <CopilotKit      runtimeUrl="/api/copilotkit-ogui"      agent="open-gen-ui"      openGenerativeUI={{ designSkill: VISUALIZATION_DESIGN_SKILL }}    >      <div className="flex justify-center items-center h-screen w-full">        <div className="h-full w-full max-w-4xl flex flex-col p-3">          <Chat />        </div>      </div>    </CopilotKit>  );

That's it. Ask the agent "build me a simple greeting card" to see HTML stream into a sandboxed preview live.

Advanced: With app tool calling#

Sandbox functions let the generated UI call back into your host application — a generated settings panel can toggle your app's theme, a product card can push items into your cart, or a data view can ask the host to fetch data the iframe can't reach directly.

"use client";/** * Open-Ended Generative UI (Advanced). * The agent-authored sandbox can call host-side functions via * `Websandbox.connection.remote.<name>(args)`. */import React from "react";import {  CopilotKit,  CopilotChat,  useConfigureSuggestions,} from "@copilotkit/react-core/v2";import { openGenUiSandboxFunctions } from "./sandbox-functions";import { openGenUiSuggestions } from "./suggestions";export default function OpenGenUiAdvancedDemo() {  return (    // Pass the sandbox-function array on the `openGenerativeUI` provider prop.    // The built-in `OpenGenerativeUIActivityRenderer` wires these as callable    // remotes inside the agent-authored iframe.    <CopilotKit      runtimeUrl="/api/copilotkit-ogui"      agent="open-gen-ui-advanced"      openGenerativeUI={{ sandboxFunctions: openGenUiSandboxFunctions }}    >      <div className="flex justify-center items-center h-screen w-full">        <div className="h-full w-full max-w-4xl">          <Chat />        </div>      </div>    </CopilotKit>  );}function Chat() {  useConfigureSuggestions({    suggestions: openGenUiSuggestions,    available: "always",  });  return (    <div className="flex h-full w-full flex-col p-3">      <CopilotChat        agentId="open-gen-ui-advanced"        className="flex-1 rounded-2xl"      />    </div>  );}

Runtime is unchanged#

The server-side flag is identical to the minimal cell; the advanced behaviour is a pure frontend addition.

route.ts

      runtime: new CopilotRuntime({        // @ts-ignore -- see main route.ts        agents,        openGenerativeUI: {          agents: ["open-gen-ui", "open-gen-ui-advanced"],        },      }),

Register sandbox functions on the provider#

Each sandbox function is a Zod-validated, host-side bridge the agent can invoke from inside the generated iframe via Websandbox.connection.remote.<name>(args). The handler runs in the host page and its description is appended to the agent's context, so the agent knows which bridges are available when generating HTML/JS.

page.tsx

import React from "react";import {  CopilotKit,  CopilotChat,  useConfigureSuggestions,} from "@copilotkit/react-core/v2";import { openGenUiSandboxFunctions } from "./sandbox-functions";import { openGenUiSuggestions } from "./suggestions";export default function OpenGenUiAdvancedDemo() {  return (    // Pass the sandbox-function array on the `openGenerativeUI` provider prop.    // The built-in `OpenGenerativeUIActivityRenderer` wires these as callable    // remotes inside the agent-authored iframe.    <CopilotKit      runtimeUrl="/api/copilotkit-ogui"      agent="open-gen-ui-advanced"      openGenerativeUI={{ sandboxFunctions: openGenUiSandboxFunctions }}    >      <div className="flex justify-center items-center h-screen w-full">        <div className="h-full w-full max-w-4xl">          <Chat />        </div>      </div>    </CopilotKit>

How the sandbox calls you back

Inside the generated UI, the agent writes JS that calls await Websandbox.connection.remote.notifyHost({ message: "hi" }). The call is proxied back to the host page, where your handler runs with the validated args.

Common use cases#

Theme toggling — generated UI controls your app's appearance
Cart / state management — product cards push items into host state
Navigation — generated UI triggers route changes in the host app
Data fetching — sandbox asks the host to fetch data the iframe can't reach directly

How streaming works#

The agent generates the tool call's parameters in an order optimized for the user experience:

placeholderMessages — shown immediately while generating
css — all styles first; the preview starts once CSS is complete
html — streams live into the preview as it's generated
jsFunctions — reusable helpers injected before expressions
jsExpressions — executed one by one; the user sees each take effect

The middleware parses the tool-call arguments incrementally and emits activity events as each parameter completes, so the preview updates progressively.

Using CDN libraries#

The sandboxed iframe can load external libraries from CDNs; just include <script> or <link> tags in the generated HTML <head>. Chart.js, D3, Three.js, and any other CDN-hosted library work out of the box.

<head>
  <script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
</head>
<body>
  <canvas id="myChart"></canvas>
</body>