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

# Create asset

> POST /v1/assets

## Introduction

Create an asset in a group. `Content-Type: application/json`; **public https URLs only** (BytePlus must fetch directly). No Base64 / Data URI / multipart upload. Upload local files to OSS / TOS / S3 first.

Both `aigc` and `liveness_face` libraries support `Image` / `Video` / `Audio`. Initial `status` is `pending`; poll until `active` (usually 1–3 minutes) before using `asset://`.

<Note>
  BytePlus `CreateAsset` no longer supports Base64 as of 2026. See [Create an Asset](https://docs.byteplus.com/en/docs/ModelArk/CreateAsset).
</Note>

## Authentication

<ParamField header="Authorization" type="string" required>
  Bearer Token, e.g. `Bearer sk-xxxxxxxxxx`
</ParamField>

## Request body

<ParamField body="url" type="string" required>
  Public https URL; passed through to upstream unchanged
</ParamField>

<ParamField body="group_id" type="string" required>
  Group ID from [Create asset group](/en/api-reference/endpoint/seedance-2.0/create-asset-group) or [Create asset group (liveness)](/en/api-reference/endpoint/seedance-2.0/create-visual-validate-session)
</ParamField>

<ParamField body="asset_type" type="string" default="Image">
  `Image` / `Video` / `Audio` (case-insensitive)
</ParamField>

<ParamField body="name" type="string">
  Display name (≤ 64 chars; UI/search only, not used in inference)
</ParamField>

## Format and size limits

#### Image (`Image`)

| Item         | Limit                                              |
| ------------ | -------------------------------------------------- |
| Formats      | jpeg / png / webp / bmp / tiff / gif / heic / heif |
| Size         | \< 30 MB                                           |
| Aspect ratio | 0.4 – 2.5                                          |
| Dimensions   | 300 – 6000 px                                      |

#### Video (`Video`)

| Item               | Limit                  |
| ------------------ | ---------------------- |
| Formats            | mp4 / mov              |
| Size               | ≤ 50 MB                |
| Resolution         | 480p, 720p (no 1080p+) |
| Duration           | 2 – 15 s               |
| FPS                | 24 – 60                |
| Aspect ratio       | 0.4 – 2.5              |
| Dimensions         | 300 – 6000 px          |
| Total pixels (W×H) | 409600 – 927408        |

#### Audio (`Audio`)

| Item     | Limit     |
| -------- | --------- |
| Formats  | mp3 / wav |
| Size     | ≤ 15 MB   |
| Duration | 2 – 15 s  |

> Gateway checks URL suffix only; BytePlus validates size/duration asynchronously. Invalid assets end as `status: failed`.

## Examples

Same JSON shape for image, video, and audio—only `asset_type` and URL differ:

```bash theme={null}
# Image
curl -X POST "https://api.gravitex.ai/v1/assets" \
  -H "Authorization: Bearer sk-xxxxxxxxxx" \
  -H "Content-Type: application/json" \
  -d '{"url":"https://your-cdn.com/portrait.jpg","group_id":"group-xxx","asset_type":"Image","name":"portrait.jpg"}'

# Video
curl -X POST "https://api.gravitex.ai/v1/assets" \
  -H "Authorization: Bearer sk-xxxxxxxxxx" \
  -H "Content-Type: application/json" \
  -d '{"url":"https://your-cdn.com/dance.mp4","group_id":"group-xxx","asset_type":"Video","name":"dance.mp4"}'

# Audio
curl -X POST "https://api.gravitex.ai/v1/assets" \
  -H "Authorization: Bearer sk-xxxxxxxxxx" \
  -H "Content-Type: application/json" \
  -d '{"url":"https://your-cdn.com/voice.mp3","group_id":"group-xxx","asset_type":"Audio","name":"voice.mp3"}'
```

## Response

```json theme={null}
{
  "virtual_id": "asset-20260508120145-pqwhc",
  "asset_url": "asset://asset-20260508120145-pqwhc",
  "group_id": "group-20260508120000-abcde",
  "asset_type": "Image",
  "status": "pending"
}
```

| Field       | Description                                           |
| ----------- | ----------------------------------------------------- |
| `asset_url` | Reference in video `content` (mapped by `asset_type`) |
| `status`    | `pending` → `active` / `failed`                       |

Next: [List assets](/en/api-reference/endpoint/seedance-2.0/list-assets) or [Get asset](/en/api-reference/endpoint/seedance-2.0/get-asset) to poll status.