# HeyGen Avatar 4 Image to Video API

> Heygen Avatar4 is HeyGen's image-to-video AI model. Bring static images to life with fluid animation, consistent character motion, and professional-grade video output.

Source: https://www.sandbase.ai/model/heygen/heygen-avatar4/image-to-video
API reference: https://www.sandbase.ai/model/heygen/heygen-avatar4/image-to-video/docs

## Facts

- Provider: HeyGen
- Type: Video model
- Model ID: `heygen/heygen-avatar4/image-to-video`
- Price: From $0.50 per run
- Capabilities: image 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": "heygen/heygen-avatar4/image-to-video",
  "image": "https://v3b.fal.media/files/b/0a90062c/A7EIviZqNxZ2HAs0yHeZ6_77a05b99-8588-4ffc-90aa-be7f9d34e9d3.png",
  "voice": "Melissa",
  "prompt": "Hey friends! Welcome to the GPU force podcast and today we are going to discuss about the rising GPU cost!",
  "resolution": "720p",
  "talking_style": "stable"
}'
```

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 HeyGen Avatar 4 Image to Video through SandBase?

Create a SandBase API key, then send requests with the model ID "heygen/heygen-avatar4/image-to-video" 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 HeyGen account?

No. One SandBase API key and balance gives you access to HeyGen Avatar 4 Image to Video and the other models in the catalog; you do not need to sign up with HeyGen separately.

## README

### HeyGen Avatar 4 Image to Video

HeyGen Avatar 4: turn a single photo into a talking presenter, driven by a script or an audio track.

#### Fields

| Field | Type | Default | Notes |
|---|---|---|---|
| `prompt` | string | — | Script to speak. |
| `image` | image URL, required | — | Photo of the presenter. JPEG, PNG, or WebP URL. |
| `audio` | audio URL | — | Optional voice track. |
| `aspect_ratio` | `16:9` / `9:16` / `4:5` / `5:4` / `1:1` | — | Output frame shape. |
| `voice` | string | `Melissa` | Voice for the script. |
| `resolution` | `360p` / `480p` / `540p` / `720p` / `1080p` | `720p` | Video resolution preset. |
| `talking_style` | `stable` / `expressive` | `stable` | `expressive` adds more head and hand motion. |

#### Billing

$0.10 per output second; length follows the audio or the spoken script. The quote before submission assumes 5 seconds.

| Output | Price |
|---|---|
| 5s | $0.50 |
| 30s | $3.00 |
| 60s | $6.00 |

Failed runs are not charged.

#### Prompting

- Use a front-facing photo with the face clearly visible.

#### Also on SandBase

Related: `heygen/avatar5/digital-twin`.