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

# Stem Separation

> Separate vocals from an existing clip and get the vocal audio URL

## Endpoint

```http theme={null}
POST /api/v1/music/stem
```

**Synchronous.** This operation runs in real time and may take up to 5 minutes. The response is returned once processing completes (no polling needed).

Separates the vocal track from an existing music clip. You can optionally specify a time range to isolate a particular vocal section.

## Request body

| Field           | Type   | Required | Description                                                                                                                                  |
| --------------- | ------ | -------- | -------------------------------------------------------------------------------------------------------------------------------------------- |
| `clip_id`       | string | **Yes**  | Clip ID to process. Obtain from [Upload Audio](/api-reference/music/upload) (`data.clipId`) or a completed generation task (`results[].id`). |
| `vocal_start_s` | float  | No       | Start time (seconds) of the section to process. Default `0`.                                                                                 |
| `vocal_end_s`   | float  | No       | End time (seconds) of the section to process. Default: full clip.                                                                            |

## Response

```json theme={null}
{
  "code": 0,
  "message": "ok",
  "request_id": "req-1710000000000",
  "data": {
    "id": "stem-abc123",
    "source_clip_id": "abc123def456",
    "status": "complete",
    "vocal_audio_url": "https://cdn.example.com/tob/stem/abc123_vocal.mp3",
    "vocal_start_s": 0,
    "vocal_end_s": 87.4
  }
}
```

| Field             | Type   | Description                           |
| ----------------- | ------ | ------------------------------------- |
| `id`              | string | Stem separation job ID                |
| `source_clip_id`  | string | The original clip ID                  |
| `status`          | string | `"complete"` when successful          |
| `vocal_audio_url` | string | URL of the extracted vocal audio file |
| `vocal_start_s`   | float  | Actual start time processed           |
| `vocal_end_s`     | float  | Actual end time processed             |

## Example

```bash theme={null}
curl -X POST https://api.example.com/api/v1/music/stem \
  -H "Authorization: Bearer sk-mm-your-key" \
  -H "Content-Type: application/json" \
  -d '{
    "clip_id": "abc123def456",
    "vocal_start_s": 30.0,
    "vocal_end_s": 90.0
  }'
```

<Note>
  The `vocal_audio_url` from this endpoint can be used as `chop_sample_clip_id` in the [Add Vocals](/api-reference/music/add-vocals) endpoint.
</Note>