# Google Veo 3.1 Video Extend API

> Veo3.1 Extend Video is Google's video-to-video AI model. Transform, enhance, and edit video content using text prompts - from style changes to object manipulation and scene modification.

Source: https://www.sandbase.ai/models/google/veo3.1/video-extend
API reference: https://www.sandbase.ai/models/google/veo3.1/video-extend/docs

## Facts

- Provider: Google
- Type: Video model
- Model ID: `google/veo3.1/video-extend`
- Price: From $2.80 per run
- Capabilities: video to video
- Billing: pay per use from one SandBase balance; no provider account or subscription needed

## Call it

- Unified Run API: `POST https://api.sandbase.ai/v1/run`

```bash
curl -X POST https://api.sandbase.ai/v1/run \
  -H "Authorization: Bearer $SANDBASE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "google/veo3.1/video-extend",
  "prompt": "Continue the scene naturally, maintaining the same style and motion.",
  "duration": 7,
  "resolution": "720p",
  "generate_audio": true
}'
```

The response returns a run id; poll `GET https://api.sandbase.ai/v1/run/{id}` until the status is `completed` or `failed`.

## FAQ

### How do I call Google Veo 3.1 Video Extend through SandBase?

Create a SandBase API key, then send requests with the model ID "google/veo3.1/video-extend" to Unified Run API (/v1/run) at https://api.sandbase.ai. The request examples on this page show the exact payload.

### Do I need a separate Google account?

No. One SandBase API key and balance gives you access to Google Veo 3.1 Video Extend and the other models in the catalog; you do not need to sign up with Google separately.

## README

### Veo 3.1 Video Extend

Veo 3.1 video extend: continue an existing Veo clip by 7 seconds, keeping its subject, motion, and audio consistent.

#### Fields

| Field | Type | Default | Notes |
|---|---|---|---|
| `prompt` | string, required | — | Up to 20,000 characters. |
| `video` | video URL, required | — | Clip to continue (a Veo-generated video works best). |
| `duration` | 7 | 7 | Output length in seconds. |
| `resolution` | `720p` | `720p` | Sets the per-second rate. |
| `aspect_ratio` | `16:9` / `9:16` | — | Output frame shape. |
| `generate_audio` | boolean | true | Native dialogue, music, and effects; turning it off lowers the rate. |
| `negative_prompt` | string | — | What to avoid. |
| `seed` | integer 0–4294967295 | random | Fix it to compare prompt changes. |

#### Billing

You pay for output seconds, Google's list price. With audio: $0.40 at 720p. Without audio: $0.20 respectively.

| Output | 720p |
|---|---|
| 7s with audio (default) | $2.80 |
| 7s without audio | $1.40 |

Failed runs are not charged.

#### Prompting

- Describe what happens next, not what is already in the clip.

#### Limits

- Each call adds 7 seconds at 720p; call again on the result to keep extending.
- Use Veo 3.1 Fast for cheaper drafts.

#### Also on SandBase

Other Veo 3.1 endpoints: `google/veo3.1/text-to-video`, `google/veo3.1/image-to-video`, `google/veo3.1/first-last-frame-to-video`, `google/veo3.1/reference-to-video`, `google/veo3.1/fast/text-to-video`, `google/veo3.1/lite/text-to-video`.