---
title: experimental_useRealtime
description: API reference for the experimental_useRealtime hook.
---

# `experimental_useRealtime()`

<Note type="warning">
  `experimental_useRealtime` is an experimental feature.
</Note>

Creates a browser-side realtime session for bidirectional audio and text
conversations with a realtime provider model.

The hook connects to a realtime WebSocket using a short-lived token from your
setup endpoint, returns messages as `UIMessage[]`, and provides controls for
audio capture, playback, text input, and tool output.

```tsx
import { openai } from '@ai-sdk/openai';
import { experimental_useRealtime } from '@ai-sdk/react';

const realtime = experimental_useRealtime({
  model: openai.experimental_realtime('gpt-realtime'),
  api: {
    token: '/api/realtime/setup',
  },
});
```

For AI Gateway, pass `gateway.experimental_realtime(...)` as the model and point
`api.token` at a server-side setup endpoint that calls
`gateway.experimental_realtime.getToken()`.

## Import

<Snippet
  text={`import { experimental_useRealtime } from "@ai-sdk/react"`}
  prompt={false}
/>

## API Signature

### Parameters

<PropertiesTable
  content={[
    {
      name: 'model',
      type: 'Experimental_RealtimeModel',
      description: 'The realtime model to connect to.',
    },
    {
      name: 'api',
      type: '{ token: string }',
      description:
        'API endpoints used by the realtime session. The token endpoint is called with POST to create the realtime setup response.',
      properties: [
        {
          type: 'Object',
          parameters: [
            {
              name: 'token',
              type: 'string',
              description:
                'The setup endpoint that returns an Experimental_RealtimeSetupResponse.',
            },
          ],
        },
      ],
    },
    {
      name: 'sessionConfig',
      type: 'Partial<Experimental_RealtimeSessionConfig>',
      isOptional: true,
      description:
        'Provider-neutral session configuration, such as instructions, voice, audio formats, input audio transcription, turn detection, tools, and providerOptions.',
    },
    {
      name: 'sampleRate',
      type: 'number',
      isOptional: true,
      description:
        'Default audio sample rate used when inputAudioFormat.rate or outputAudioFormat.rate is not specified. Defaults to 24000.',
    },
    {
      name: 'maxEvents',
      type: 'number',
      isOptional: true,
      description:
        'Maximum number of provider events to keep in the events array. Defaults to 500.',
    },
    {
      name: 'onToolCall',
      type: '(options: { toolCall: { toolCallId: string; toolName: string; args: unknown } }) => unknown | Promise<unknown> | undefined',
      isOptional: true,
      description:
        'Called when the provider requests a tool call. Return a value to automatically submit it as tool output, or return undefined and call addToolOutput manually later.',
    },
    {
      name: 'onEvent',
      type: '(event: Experimental_RealtimeServerEvent) => void',
      isOptional: true,
      description: 'Called for every normalized realtime server event.',
    },
    {
      name: 'onError',
      type: '(error: Error) => void',
      isOptional: true,
      description: 'Called when the realtime session encounters an error.',
    },
  ]}
/>

### Returns

<PropertiesTable
  content={[
    {
      name: 'status',
      type: "'disconnected' | 'connecting' | 'connected' | 'error'",
      description: 'The current connection status.',
    },
    {
      name: 'messages',
      type: 'UIMessage[]',
      description:
        'Messages assembled from realtime text, transcript, and tool events.',
    },
    {
      name: 'events',
      type: 'Experimental_RealtimeServerEvent[]',
      description:
        'Recent normalized provider events for inspection or debug UI.',
    },
    {
      name: 'isCapturing',
      type: 'boolean',
      description: 'Whether microphone audio capture is active.',
    },
    {
      name: 'isPlaying',
      type: 'boolean',
      description: 'Whether model audio playback is active.',
    },
    {
      name: 'connect',
      type: '() => Promise<void>',
      description:
        'Fetches the setup token and opens the provider WebSocket connection.',
    },
    {
      name: 'disconnect',
      type: '() => void',
      description: 'Closes the provider WebSocket connection.',
    },
    {
      name: 'addToolOutput',
      type: '(callId: string, result: unknown) => void',
      description:
        'Submits the result for a tool call back to the realtime provider.',
    },
    {
      name: 'sendEvent',
      type: '(event: Experimental_RealtimeClientEvent) => void',
      description: 'Sends a normalized realtime client event.',
    },
    {
      name: 'sendTextMessage',
      type: '(text: string) => void',
      description: 'Sends a user text message and requests a response.',
    },
    {
      name: 'sendAudio',
      type: '(base64Audio: string) => void',
      description:
        'Sends a base64-encoded audio chunk to the provider input audio buffer.',
    },
    {
      name: 'commitAudio',
      type: '() => void',
      description: 'Commits the provider input audio buffer.',
    },
    {
      name: 'clearAudioBuffer',
      type: '() => void',
      description: 'Clears the provider input audio buffer.',
    },
    {
      name: 'requestResponse',
      type: '(options?: { modalities?: string[] }) => void',
      description: 'Requests a new model response.',
    },
    {
      name: 'cancelResponse',
      type: '() => void',
      description: 'Cancels the active model response.',
    },
    {
      name: 'startAudioCapture',
      type: '(stream: MediaStream) => void',
      description:
        'Starts capturing microphone audio from the provided MediaStream.',
    },
    {
      name: 'stopAudioCapture',
      type: '() => void',
      description: 'Stops microphone audio capture.',
    },
    {
      name: 'stopPlayback',
      type: '() => void',
      description: 'Stops queued model audio playback.',
    },
  ]}
/>

## Tool Calling

Realtime tool execution is client-driven. Use `onToolCall` to handle tool calls
and return the tool output:

```tsx
const realtime = experimental_useRealtime({
  model: openai.experimental_realtime('gpt-realtime'),
  api: {
    token: '/api/realtime/setup',
  },
  onToolCall: async ({ toolCall }) => {
    if (toolCall.toolName === 'getWeather') {
      const response = await fetch('/api/weather', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(toolCall.args),
      });

      return response.json();
    }
  },
});
```

For tools that require user interaction, return `undefined` from `onToolCall`
and call `addToolOutput` later.

See [Realtime](/docs/ai-sdk-core/realtime#tool-calling) for a complete example
with server-backed app-specific tool endpoints.
