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

# seedance-2-fast-ext Video Generation

> Generate videos quickly at low cost with the seedance-2-fast-ext model

`seedance-2-fast-ext` is the volume promotional-channel model in the Seedance 2.0 family, designed for low-cost, fast generation:

* Text-to-video and reference-image generation
* Supports `480p`, `720p`, and `1080p` output
* Reference videos, reference audios, first/last-frame control, and video editing are not supported
* The API is asynchronous: submitting returns a `generation.task`; fetch results via the [video task status endpoint](../../tasks/video-status).

## Authentication

<ParamField header="Authorization" type="string" required>
  All requests require a Bearer Token. Get your key from the [API Key management page](https://toapis.com/console/token) and add it to the request header:

  ```text theme={null}
  Authorization: Bearer YOUR_API_KEY
  ```
</ParamField>

## Body

<ParamField body="model" type="string" default="seedance-2-fast-ext" required>
  ToAPIs public model name. Always use `seedance-2-fast-ext`.
</ParamField>

<ParamField body="prompt" type="string">
  Describe the scene, camera movement, subject actions, style, and sound atmosphere.
</ParamField>

<ParamField body="seconds" type="integer" default="5">
  Output video duration in seconds. Only `5`, `10`, and `15` are supported. The compatible field `duration` is also accepted; do not pass both.
</ParamField>

<ParamField body="size" type="string">
  Output aspect ratio. Supported: `16:9`, `9:16`, `4:3`, `3:4`, `1:1`. The compatible field `aspect_ratio` is also accepted.
</ParamField>

<ParamField body="resolution" type="string" default="720p">
  Output resolution. Supported: `480p`, `720p`, and `1080p`.
</ParamField>

<ParamField body="reference_image" type="string">
  Public URL of a single reference image. For multiple images use `reference_images`.
</ParamField>

<ParamField body="reference_images" type="string[]">
  Array of reference image URLs, up to `9`. You can also use `image_with_roles` with `role` set to `reference_image`.
</ParamField>

<ParamField body="callback_url" type="string">
  ToAPIs task completion callback URL. See [Task Webhooks](/docs/en/api-reference/webhooks/task-webhooks).
</ParamField>

<ParamField body="client_business_id" type="string">
  Your order number or business task ID. Stored with the task; you can also query it via `GET /v1/videos/generations/{client_business_id}`.
</ParamField>

<ParamField body="trace_id" type="string">
  Custom trace ID for request tracking.
</ParamField>

## Media Combination Rules

| Request content | Supported | Notes |
| - | -: | - |
| Prompt only | Yes | Text-to-video |
| Reference images | Yes | Up to 9 |
| Reference video / reference audio | No | Use `seedance-2.5-ext` instead |
| First / last frame | No | Frame mode is not supported |

## Request Examples

### Text-to-Video

```bash theme={null}
curl --request POST \
  --url https://toapis.com/v1/videos/generations \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
    "model": "seedance-2-fast-ext",
    "prompt": "Waves crashing on rocks, camera slowly orbiting in.",
    "seconds": 5,
    "size": "16:9",
    "resolution": "720p"
  }'
```

### Reference Image

```bash theme={null}
curl --request POST \
  --url https://toapis.com/v1/videos/generations \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
    "model": "seedance-2-fast-ext",
    "prompt": "The character in image 1 blinks and smiles.",
    "seconds": 5,
    "size": "9:16",
    "resolution": "480p",
    "reference_images": [
      "https://example.com/avatar.png"
    ]
  }'
```

## Response

<ResponseField name="id" type="string">Task ID for status queries.</ResponseField>
<ResponseField name="client_business_id" type="string">Returned when provided in the request.</ResponseField>
<ResponseField name="object" type="string">Fixed to `generation.task`.</ResponseField>
<ResponseField name="model" type="string">The model used for this request.</ResponseField>
<ResponseField name="status" type="string">`queued`, `in_progress`, `completed`, or `failed`.</ResponseField>
<ResponseField name="progress" type="integer">Task progress from `0` to `100`.</ResponseField>
<ResponseField name="created_at" type="integer">Creation timestamp.</ResponseField>

<ResponseExample>
  ```json 200 theme={null}
  {
    "id": "tsk_vid_xxx",
    "object": "generation.task",
    "model": "seedance-2-fast-ext",
    "status": "in_progress",
    "progress": 10,
    "created_at": 1781577600
  }
  ```
</ResponseExample>


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