# Tutorial: Build an in-app documentation assistant

> Build and embed an in-app documentation assistant that answers user questions with cited information from your Mintlify documentation site.

## What you'll build

A reusable widget that embeds the [assistant](https://www.mintlify.com/docs/assistant/index) directly in your application. The widget provides:

- A floating button that opens a chat panel when clicked
- Real-time streaming responses based on information from your documentation
- Message rendering with Markdown support

Users can use the widget to get help with your product without leaving your application.

:::frame
![Demo of the assistant widget being opened and the user typing in How do I get started? Then the assistant responds.](../img/site-assets/mintcdn.com/mintlify/14gofcrk-ET1sjS3/images/assistant/assistant-embed-demo-s46d6.gif)
:::

## Prerequisites

- The Mintlify assistant enabled
- Your domain name, which appears at the end of your dashboard URL. For example, if your dashboard URL is `https://app.mintlify.com/org-name/domain-name`, your domain name is `domain-name`
- An [assistant API key](https://app.mintlify.com/settings/organization/api-keys)
- Node.js v18 or higher and npm installed
- Basic React knowledge

### Get your assistant API key

1. Navigate to the [API keys](https://app.mintlify.com/settings/organization/api-keys) page in your dashboard.
2. Click **Create Assistant API Key**.
3. Copy the assistant API key (starts with `mint_dsc_`) and save it securely.

:::callout{intent="note"}
Your assistant API key controls access to your assistant quota. This tutorial keeps the key server-side using a backend proxy so it never reaches the client bundle.
:::

## Set up the example

Clone the [example repository](https://github.com/mintlify/assistant-embed-example) and customize it for your needs.

:::::steps
:::step{title="Clone the repository"}
```bash theme={null}
git clone https://github.com/mintlify/assistant-embed-example.git
cd assistant-embed-example
```
:::

::::step{title="Choose your development tool"}
The repository includes Next.js and Vite examples. Choose the tool you prefer to use.

:::code-group
```bash title="Next.js" theme={null}
cd nextjs
npm install
```

```bash title="Vite" theme={null}
cd vite
npm install
```
:::
::::

:::step{title="Configure your project"}
Open `src/config.js` and update with your Mintlify project details.

```js src/config.js theme={null}
export const ASSISTANT_CONFIG = {
  domain: 'your-domain',
  docsURL: 'https://yourdocs.mintlify.site',
};
```

Replace:

- `your-domain` with your Mintlify project domain found at the end of your dashboard URL.
- `https://yourdocs.mintlify.site` with your actual documentation URL.
:::

:::step{title="Set up your API key"}
Store your assistant API key as a server-side environment variable. Avoid the `VITE_` prefix, which bundles the value into your client code:

```bash .env theme={null}
MINTLIFY_TOKEN=mint_dsc_your_token_here
```

Replace `mint_dsc_your_token_here` with your assistant API key.

Then add a backend route (for example, `/api/assistant`) to proxy requests to the Mintlify API:

1. Accept the user's message from the widget.
2. Attach the `Authorization: Bearer $MINTLIFY_TOKEN` header and forward the request to `https://api.mintlify.com/discovery/v1/assistant/{domain}/message`.
3. Stream the upstream response back to the client unchanged, so token streaming and `X-Thread-Id` / `X-Thread-Key` headers reach the widget.
4. Point the widget's `api` option at your backend route instead of the Mintlify API directly.
:::

:::step{title="Start the development server"}
```bash theme={null}
npm run dev
```

Open your application in a browser and click the **Ask** button to open the assistant widget.
:::
:::::

## Customization ideas

### Source citations

Extract and display sources from assistant responses:

```jsx theme={null}
const extractSources = (parts) => {
  return parts
    ?.filter(p => p.type === 'tool-invocation' && p.toolInvocation?.toolName === 'search')
    .flatMap(p => p.toolInvocation?.result || [])
    .map(source => ({
      url: source.url || source.path,
      title: source.metadata?.title || source.path,
    })) || [];
};

// In your message rendering:
{messages.map((message) => {
  const sources = message.role === 'assistant' ? extractSources(message.parts) : [];
  return (
    <div key={message.id}>
      {/* message content */}
      {sources.length > 0 && (
        <div className="mt-2 text-xs">
          <p className="font-semibold">Sources:</p>
          {sources.map((s, i) => (
            <a key={i} href={s.url} target="_blank" rel="noopener noreferrer" className="text-blue-600">
              {s.title}
            </a>
          ))}
        </div>
      )}
    </div>
  );
})}
```

### Track conversation threads

Store thread IDs and thread keys to maintain conversation history across sessions.

When a user creates a new conversation thread, the server returns two values in the response headers:

- `X-Thread-Id`: The thread identifier
- `X-Thread-Key`: A secret key for the thread (only returned once, when you create the thread)

You must capture and persist both values on the first response. On every subsequent message, include both `threadId` and `threadKey` in the request body. If you send a `threadId` without the corresponding `threadKey`, the server returns a `404` error.

:::callout{intent="warning"}
You must store the `X-Thread-Key` header immediately. The server only returns it when you create a new thread. You cannot retrieve it later.
:::

```jsx theme={null}
import { useState, useEffect } from 'react';

export function AssistantWidget({ domain, docsURL }) {
  const [threadId, setThreadId] = useState(null);
  const [threadKey, setThreadKey] = useState(null);

  useEffect(() => {
    // Retrieve saved thread ID and key from localStorage
    const savedId = localStorage.getItem('assistant-thread-id');
    const savedKey = localStorage.getItem('assistant-thread-key');
    if (savedId && savedKey) {
      setThreadId(savedId);
      setThreadKey(savedKey);
    }
  }, []);

  const { messages, input, handleInputChange, handleSubmit, isLoading } = useChat({
    api: '/api/assistant',
    body: {
      fp: 'anonymous',
      retrievalPageSize: 5,
      ...(threadId && { threadId }),
      ...(threadKey && { threadKey }),
    },
    streamProtocol: 'data',
    sendExtraMessageFields: true,
    fetch: async (url, options) => {
      const response = await fetch(url, options);
      const newThreadId = response.headers.get('x-thread-id');
      const newThreadKey = response.headers.get('x-thread-key');
      if (newThreadId) {
        setThreadId(newThreadId);
        localStorage.setItem('assistant-thread-id', newThreadId);
      }
      if (newThreadKey) {
        setThreadKey(newThreadKey);
        localStorage.setItem('assistant-thread-key', newThreadKey);
      }
      return response;
    },
  });

  // ... rest of component
}
```

### Add keyboard shortcuts

Allow users to open the widget and submit messages with keyboard shortcuts:

```jsx theme={null}
useEffect(() => {
  const handleKeyDown = (e) => {
    // Cmd/Ctrl + Shift + I to toggle widget
    if ((e.metaKey || e.ctrlKey) && e.shiftKey && e.key === 'I') {
      e.preventDefault();
      setIsOpen((prev) => !prev);
    }

    // Enter (when widget is focused) to submit
    if (e.key === 'Enter' && !e.shiftKey && document.activeElement.id === 'assistant-input') {
      e.preventDefault();
      handleSubmit();
    }
  };

  window.addEventListener('keydown', handleKeyDown);
  return () => window.removeEventListener('keydown', handleKeyDown);
}, [handleSubmit]);
```

## Related topics

- [Guides](/docs/guides/index.md)
- [Assistant](/docs/assistant/index.md)
- [Quickstart](/docs/quickstart.md)

## Related pages

- [Ai](./ai-index.md)
- [Analytics overview](./analytics-index.md)
- [Api](./api-index.md)
- [Api playground](./api-playground-index.md)
- [Assistant](./assistant-index.md)
- [Automations overview](./automations-index.md)
- [Components overview](./components-index.md)
- [Create](./create-index.md)
- [Customize](./customize-index.md)
- [Dashboard](./dashboard-index.md)

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