# Alibaba Wan 3.0 Video Extend API

> Wan 3.0 Video Extend by Alibaba continues an input video forward from a text instruction, optionally guided by reference images and audio, with native audio.

Source: https://www.sandbase.ai/models/alibaba/wan/3.0/video-extend
API reference: https://www.sandbase.ai/models/alibaba/wan/3.0/video-extend/docs

## Facts

- Provider: Alibaba
- Type: Video model
- Model ID: `alibaba/wan/3.0/video-extend`
- Price: From $1.30 per run (35% off list price)
- 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": "alibaba/wan/3.0/video-extend",
  "video": "https://help-static-aliyun-doc.aliyuncs.com/file-manage-files/zh-CN/20260402/ldnfdf/wan2.7-videoedit-style-change.mp4",
  "duration": 5,
  "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 Alibaba Wan 3.0 Video Extend through SandBase?

Create a SandBase API key, then send requests with the model ID "alibaba/wan/3.0/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 Alibaba account?

No. One SandBase API key and balance gives you access to Alibaba Wan 3.0 Video Extend and the other models in the catalog; you do not need to sign up with Alibaba separately.

## README

### Wan 3.0 Video Extend

Continue a clip past its last frame. The model carries over the subject, look, and camera language of the source and generates the next beat you describe. The response contains the new segment only, so you can cut it onto the original yourself.

#### Fields

| Field | Type | Default | Notes |
|---|---|---|---|
| `prompt` | string, required | — | Up to 5,000 characters. |
| `video` | video URL, required | — | Source clip, Video 1 in the prompt. MP4/MOV, 1–15s, ≥16fps, 240–4096px per side, ≤100MB. |
| `images` | image URL[] (≤10) | — | Referenced as Image 1, Image 2, … |
| `audios` | audio URL[] (≤5) | — | WAV/MP3, 1–15s each, 15s total, ≤15MB. Referenced as Audio 1, … |
| `duration` | 2–30 or `auto` | 5 | Length of the new segment. Source + duration ≤ 30s. |
| `resolution` | `480p` / `720p` / `1080p` | `720p` | Sets the per-second rate. |
| `generate_audio` | boolean | true | Native dialogue, music, and effects. Same price on or off. |
| `seed` | integer 0–2147483647 | random | Fix it to compare prompt changes. |

The aspect ratio always follows the source, so there is no `aspect_ratio` field.

#### Billing

Following the official Wan 3.0 rule, billed seconds are the source clip length (rounded up) plus the new segment: $0.05 at 480p, $0.10 at 720p, $0.20 at 1080p per second. References are not metered. If the source length cannot be read, 15s is assumed, which is also what the listed starting price uses.

| Source + new segment | Billed | 480p | 720p | 1080p |
|---|---|---|---|---|
| 5s + 5s | 10s | $0.50 | $1.00 | $2.00 |
| 10s + 5s | 15s | $0.75 | $1.50 | $3.00 |
| 15s + 5s (default) | 20s | $1.00 | $2.00 | $4.00 |
| 15s + 15s | 30s | $1.50 | $3.00 | $6.00 |

With `duration: "auto"` the run is pre-authorized at 30 seconds, then settled on the length that was actually generated. Failed runs are not charged. Output files are copied to SandBase storage and the returned URL stays valid for 7 days; download anything you need to keep.

#### Prompting

- Describe what happens next, not what the source already shows: “Extend Video 1 forward: the baker carries the tray to the oven and the camera follows.”
- Mention the subject and direction of movement again if continuity matters.
- Keep the source short when you need a long extension; both count toward 30 seconds.

#### Limits

- The returned video is the extension only; the source is not included.
- To change the existing footage instead, use video-edit.

#### Also on SandBase

Other Wan 3.0 endpoints: `alibaba/wan/3.0/video` (all modes in one schema), `alibaba/wan/3.0/text-to-video`, `alibaba/wan/3.0/image-to-video`, `alibaba/wan/3.0/reference-to-video`, `alibaba/wan/3.0/video-edit`.