Asset Upload and Management

Seedance 2.0 / 2.5 automatically detects and uploads HTTPS assets, with optional manual upload for asset:// reuse.

Seedance 2.0 / 2.5 supports automatic asset uploads: pass publicly accessible https:// URLs directly in the image, video, or audio input fields of your video generation request. ModelSell automatically detects and uploads these assets, so you do not need to call the asset upload endpoint beforehand.

To reuse assets by ID, you can also follow the manual /api/assets/upload workflow below. Once the asset becomes Active, reference it in video generation requests with asset://<asset_id>. Asset APIs use the same user API key authentication as the rest of the API.

The asset upload API supports both domestic and overseas model versions. Domestic models do not need the model query parameter. For the overseas dreamina-seedance-2-0-fast-260128 model, add ?model=dreamina-seedance-2-0-fast-260128 so the request is routed to the matching overseas asset channel.

Endpoints

Operation	Endpoint
Upload asset	`POST /api/assets/upload`
Get asset	`GET /api/assets/{id}`

Upload Rules

Asset upload accepts URLs only. Base64 input is not supported for this endpoint.

Type	Formats	Limits
`Image`	jpeg, png, webp, bmp, tiff, gif, heic, heif	Aspect ratio 0.4 to 2.5; width or height 300 to 6000 px; under 30MB
`Video`	mp4, mov	480p or 720p; 2 to 15 seconds; aspect ratio 0.4 to 2.5; width or height 300 to 6000 px; up to 50MB; 24 to 60 FPS
`Audio`	wav, mp3	2 to 15 seconds; up to 15MB

Upload an Asset

Domestic Model

curl -X POST "$MODELSELL_BASE_URL/api/assets/upload" \
  -H "Authorization: Bearer $MODELSELL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://example.com/image.png",
    "asset_type": "Image",
    "name": "Example image"
  }'

Overseas Model

curl -X POST "$MODELSELL_BASE_URL/api/assets/upload?model=dreamina-seedance-2-0-fast-260128" \
  -H "Authorization: Bearer $MODELSELL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://example.com/image.png",
    "asset_type": "Image",
    "name": "Example image"
  }'

Save data.Id from the response:

{
  "code": 0,
  "message": "ok",
  "data": {
    "Id": "asset-20260325152211-vcchd"
  }
}

Get Asset Details

curl "$MODELSELL_BASE_URL/api/assets/asset-20260325152211-vcchd?model=dreamina-seedance-2-0-fast-260128" \
  -H "Authorization: Bearer $MODELSELL_API_KEY"

Example response:

{
  "code": 0,
  "message": "ok",
  "data": {
    "AssetType": "Image",
    "CreateTime": "2026-03-25T15:22:11Z",
    "GroupId": "group-20260324135506-xxxxx",
    "Id": "asset-20260325152211-vcchd",
    "Name": "Example image",
    "ProjectName": "default",
    "Status": "Active",
    "URL": "https://example.com/image.png",
    "UpdateTime": "2026-03-25T15:22:11Z"
  }
}

When the detail response has Status: "Active", the asset can be used in generation requests.

Use Assets in Video Generation

Official Seedance 2.0 content[] format:

{
  "model": "doubao-seedance-2-0-260128",
  "content": [
    {
      "type": "text",
      "text": "Make the character dance"
    },
    {
      "type": "image_url",
      "image_url": {
        "url": "asset://asset-20260325152211-vcchd"
      },
      "role": "reference_image"
    }
  ],
  "resolution": "480p",
  "ratio": "16:9",
  "duration": 5,
  "watermark": false
}

Generic /v1/video/generations format:

{
  "model": "doubao-seedance-2-0-260128",
  "prompt": "Make the character dance",
  "image": "asset://asset-20260325152211-vcchd",
  "duration": 5,
  "size": "480p",
  "metadata": {
    "ratio": "16:9",
    "watermark": false
  }
}

Video and audio assets use the same asset://<asset_id> format in metadata.video_url and metadata.audio_url.