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

# Grok Imagine Video Extend (URL)

> Extend any video given by URL with xAI Grok Imagine. See parameters, pricing, and API examples.

Continue any video by URL using xAI's Grok Imagine. Provide the public URL of the clip, describe what happens next, and choose how many seconds of new video to add.

<Note>
  This model takes a **`video_url`** and works on any video, including output from [Grok Imagine Video 1.5](/models/video/xai/grok-imagine-1.5-video) and [Grok Imagine Video 1.5 Lite](/models/video/xai/grok-imagine-1.5-lite-video). [Grok Imagine 1.5 Fast Video Extend](/models/video/xai/grok-imagine-video-extend) (`xai/grok-imagine-video-extend`) takes a **`task_id`** instead and only accepts tasks from `xai/grok-imagine-1.5-fast-video`.
</Note>

## Model

```
xai/grok-imagine-video-api-extend
```

## Pricing

Billed per second of generated video plus a per-second charge for the source video. The per-second tier is decided by the source clip's resolution.

| Source clip resolution | Per generated second | Per source second |
| - | - | - |
| 480p | \$0.025 | \$0.005 |
| 720p | \$0.035 | \$0.005 |

Example: adding 6 seconds to a 10-second 720p clip costs 6 × $0.035 + 10 × $0.005 = \$0.26.

## Parameters

| Parameter | Type | Required | Default | Description |
| - | - | - | - | - |
| `prompt` | string | Yes | — | What happens in the new seconds |
| `video_url` | string | Yes | — | Public URL of the clip to continue |
| `duration` | int | No | `6` | Seconds of new video to add, `2`–`10` |

<Note>
  Unknown request fields are rejected rather than ignored.
</Note>

## Example Request

```bash theme={null}
curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "xai/grok-imagine-video-api-extend",
    "input": {
      "prompt": "The camera keeps panning right to reveal a mountain range",
      "video_url": "https://example.com/source-clip.mp4",
      "duration": 6
    }
  }'
```

## Response

```json theme={null}
{
  "code": 200,
  "success": true,
  "data": {
    "task_id": "abc123def456",
    "status": "processing"
  }
}
```

<Note>
  **Volume discounts** are available for almost all models. Reach out at [contact@unifically.com](mailto:contact@unifically.com) to discuss custom pricing.
</Note>


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