> ## Documentation Index
> Fetch the complete documentation index at: https://docs.urantia.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Audio Narration API - Listen to the Urantia Book

> Access multi-voice TTS audio for every paragraph of the Urantia Book. 7 voices, 3 models, full coverage of 14,500+ paragraphs.

Every paragraph includes an `audio` field — a nested object keyed by TTS model and voice, or `null` if no audio exists.

## Response shape

```json theme={null}
{
  "audio": {
    "tts-1-hd": {
      "nova": {
        "format": "mp3",
        "url": "https://cdn.urantia.dev/audio/eng/paragraphs/nova/tts-1-hd-nova-0:0.0.1.mp3",
        "bitrate": 160,
        "duration": 43.3,
        "fileSize": 866400
      }
    },
    "gpt-4o-mini-tts": {
      "cedar": {
        "format": "mp3",
        "url": "https://cdn.urantia.dev/audio/eng/paragraphs/cedar/gpt-4o-mini-tts-cedar-0:0.0.1.mp3",
        "bitrate": 192,
        "duration": 41.7,
        "fileSize": 1002518
      }
    }
  }
}
```

`bitrate` is in kbps, `duration` in seconds, and `fileSize` in bytes.

## Available models and voices

Coverage varies per paragraph. Only the `tts-1-hd` / `nova` combination covers every paragraph. Read the `audio` object rather than building URLs by hand — a voice that is absent for a paragraph is absent from the object.

| Model | Voices | Coverage |
| - | - | - |
| `tts-1-hd` | `nova` | Full — all 14,500+ paragraphs |
| `gpt-4o-mini-tts` | `cedar` | Partial — roughly 3,400 paragraphs |
| `tts-1-hd` | `onyx` | Partial — a few hundred paragraphs |
| `tts-1-hd` | `echo`, `alloy`, `fable`, `shimmer` | Samples only |
| `tts-1` | `alloy` | Samples only |

## Accessing audio

Audio URLs are included in responses from all paragraph-returning endpoints: `/search`, `/paragraphs/*`, `/papers/:id`, and the dedicated `/audio/:ref` endpoint.

```bash theme={null}
# Get just the audio info for a paragraph
curl https://api.urantia.dev/audio/119:1.5
```

All audio files are served from `cdn.urantia.dev` via Cloudflare CDN. See [CDN & Static Assets](/cdn) for the URL patterns and for paper-level audio.


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