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

# Internal Project Voice Sample Preview

> Authenticated app route for generating a temporary cloned voice preview from a dubbing project

# Internal Project Voice Sample Preview

This is an internal authenticated backend route used by the VoiceCheap app. It is not part of the public API key surface.

## Route

* Method: `POST`
* Path: `/speech/project-voice-sample-preview`
* Auth: Bearer access token required

## Request body

```json theme={null}
{
  "projectId": "project_123",
  "speakerNumber": 0,
  "voiceCloningSettings": {
    "stability": 0.6,
    "similarity": 0.8,
    "speakerBoost": 0.6
  }
}
```

## Response

```json theme={null}
{
  "speakerNumber": 0,
  "audioBase64": "<base64-mp3>",
  "mimeType": "audio/mpeg"
}
```

## Behavior

* Resolves the project and checks the requester has access.
* Downloads the stored original audio.
* Cuts and concatenates the selected speaker audio from the project transcription.
* Caps source speech at 5 minutes per speaker.
* Creates a temporary cloned voice, generates one preview sentence in the first target language, then deletes the temporary voice.
* Returns the preview as base64 MP3 data for immediate playback in the app.

## Rate limiting

* This route is intentionally low-rate-limit.
* `429` response:

```json theme={null}
{
  "code": "PROJECT_VOICE_SAMPLE_RATE_LIMIT_REACHED",
  "message": "Voice previews are limited right now. Please wait a few minutes before generating another sample."
}
```

## Project data changes

Project creation now stores persisted examples on the dubbing project under `voicePreviewSamples[]`:

```json theme={null}
[
  {
    "speakerNumber": 0,
    "audioUrl": "https://...",
    "targetLanguage": "french",
    "createdAt": 1741950000000
  }
]
```

Stored `voicePreviewSamples[].audioUrl` files are deleted when the project is deleted.