> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.vapi.ai/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.vapi.ai/_mcp/server.

# Smallest AI

> Connect Smallest AI to Vapi to use its low-latency text-to-speech voices for your voice agent. Covers the model and how to select a voice in the API.

Smallest AI is a text-to-speech provider you can use for your voice agent's voice. Connect Smallest AI to use its voices on a Vapi assistant. This page covers what Smallest AI is and how to select a voice.

## What is Smallest AI

Smallest AI is a text-to-speech provider focused on low-latency speech synthesis. On Vapi, you select a Smallest AI voice for an assistant.

You can use Smallest AI through Vapi's default integration, or use your own Smallest AI account by connecting it in [Integrations](/providers/integrations).

## Text-to-speech

Set `voice.provider` to `smallest-ai`, `voice.model` to `lightning`, and `voice.voiceId` to a voice. Smallest AI offers many voices, you can browse and copy a voice's ID from the [Voice Library](/providers/voice/overview).

```bash
curl -X PATCH "https://api.vapi.ai/assistant/ASSISTANT_ID" \
  -H "Authorization: Bearer $VAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "voice": { "provider": "smallest-ai", "model": "lightning", "voiceId": "emily" }
  }'
```

For additional API configuration options, review the [`SmallestAIVoice` fields](/api-reference/assistants/create#request.body.voice.SmallestAIVoice) in the Create Assistant API reference.

## Supported languages

Smallest AI text-to-speech has no separate language setting. The Lightning model detects the language from the input text and supports multiple languages.

## Related

#### [Voices](/providers/voice/overview)

Compare every text-to-speech provider Vapi supports.