Video model · ByteDance

Seedance 2.0 Fast API

Seedance 2.0 Fast is the lower-cost Fast model of ByteDance's Seedance 2.0 series. It takes the same requests as Seedance 2.0 Pro: create a task, then poll it until the video URL is ready.

Model ID: seedance-2-0-fast
Input: Text, images
Output: Video with audio
Mode: Async task

Capabilities

Capabilities & endpoints

Video generation is asynchronous: create a task, then poll it. A 4-second 480p clip took 3.5 to 4 minutes in testing.

POSThttps://tokenra.io/v1/video/generationsTested

Create a task. Returns task_id immediately.

GEThttps://tokenra.io/v1/video/generations/{task_id}Tested

Query the task. The video link is in data.result_url when data.status is SUCCESS.

Modes

Generation modes

All three request shapes produced a video on 2026-10-23.

A. Text to video

Only a prompt. Output settings go in metadata.

{
  "model": "seedance-2-0-fast",
  "prompt": "A paper boat drifting down a rainy neon street at night, cinematic close-up",
  "metadata": {
    "resolution": "720p",
    "ratio": "16:9",
    "duration": 5
  }
}

B. Image to video (first frame)

Put image URLs in images; one image is used as the first frame.

{
  "model": "seedance-2-0-fast",
  "prompt": "The girl in the picture turns around and smiles",
  "images": ["https://example.com/first-frame.png"],
  "metadata": {"resolution": "720p", "duration": 5}
}

C. Reference images

To give images a role, send Volcengine Ark content items inside metadata. The prompt is added as the text item automatically.

{
  "model": "seedance-2-0-fast",
  "prompt": "The character from image 1 walks into the room from image 2",
  "metadata": {
    "resolution": "720p",
    "ratio": "16:9",
    "content": [
      {
        "type": "image_url",
        "image_url": {"url": "https://example.com/character.png"},
        "role": "reference_image"
      },
      {
        "type": "image_url",
        "image_url": {"url": "https://example.com/room.png"},
        "role": "reference_image"
      }
    ]
  }
}

Request

Request parameters

Put output settings in metadata

Top-level resolution, ratio and duration are ignored for Seedance 2.0. A test on 2026-10-23 with top-level ratio: "9:16" and duration: 4 produced a 16:9, 5-second video, while metadata.resolution was applied. With the same values in metadata, the video was 9:16 and 4 seconds long.

Top-level fields

Parameter	Type	Required	Description
`model`	string	Yes	`seedance-2-0-fast`. `seedance-2-0-pro` and `seedance-2-0-mini` take the same parameters.
`prompt`	string	Yes	Describe the scene, the motion and the camera.
`images`	string[]	No	Image URLs. Plain strings only; use `metadata.content` when you need roles.
`metadata`	object	No	Output settings and Ark-native fields, see the next table.

metadata fields

Parameter	Type	Required	Description
`resolution`	string	No	`480p`, `720p` or `1080p`; `480p` was tested. Also decides the price.
`ratio`	string	No	`16:9`, `9:16`, `4:3`, `3:4`, `1:1`, `21:9` or `adaptive`. `16:9` and `9:16` were tested.
`duration`	integer	No	Length in seconds, 4 to 15. Default 5; `4` was tested.
`generate_audio`	boolean	No	Generate a matching soundtrack. On by default: every test video had an audio track.
`seed`	integer	No	Random seed for repeatable results.
`camera_fixed`	boolean	No	Keep the camera still.
`watermark`	boolean	No	Add the upstream watermark.
`content`	array	No	Ark material items: `image_url` with `role` such as `first_frame`, `last_frame` or `reference_image`.

Response

Response format

Create response

{
  "id": "task_FUhA4FK80TV1p70mpHlyZXCxeHR0dPPa",
  "task_id": "task_FUhA4FK80TV1p70mpHlyZXCxeHR0dPPa",
  "object": "video",
  "model": "seedance-2-0-fast",
  "status": "queued",
  "progress": 0,
  "created_at": 1792766873
}

Query response

{
  "code": "success",
  "message": "",
  "data": {
    "task_id": "task_FUhA4FK80TV1p70mpHlyZXCxeHR0dPPa",
    "action": "generate",
    "status": "SUCCESS",
    "fail_reason": "",
    "result_url": "https://example.com/output.mp4",
    "submit_time": 1792766873,
    "start_time": 1792766890,
    "finish_time": 1792767085,
    "progress": "100%",
    "data": {"resolution": "720p", "ratio": "16:9", "duration": 5, "...": "..."}
  }
}

data.data holds the raw upstream task, including the resolution, ratio and duration that were actually used.

data.status	Meaning
`NOT_START` / `SUBMITTED` / `QUEUED`	Accepted, waiting to start.
`IN_PROGRESS`	Generating.
`SUCCESS`	Done. Download `result_url`.
`FAILURE`	Failed. The reason is in `fail_reason`; the pre-charged amount is refunded.

Errors

Errors & limits

Common errors

HTTP	error.code	Meaning	What to do
`401`	—	Missing, wrong or deleted API key. The message is `Invalid token`.	Check the `Authorization: Bearer` header and the key in the console.
`400`	—	The body is not valid JSON.	Fix the JSON and send `Content-Type: application/json`.
`500`	`invalid_request`	A required field is missing, for example `messages`.	Add the field named in the message. Retrying will not help.
`403`	`insufficient_user_quota`	Your balance or plan quota is used up.	Top up in the console, then retry.
`503`	`model_not_found`	Unknown model ID, or no channel serves it for your group.	Check the ID in the model list or with `GET /v1/models`.
`429`	—	Too many requests.	Back off exponentially and retry.
`5xx`	—	The upstream provider failed or timed out.	Retry a few times; keep the request id if it persists.

Limits and notes

Poll every 10–15 seconds. Test tasks (4 s, 480p) finished in 3.5 to 4 minutes.
result_url is a temporary link. Download and store the video yourself.
The price depends on metadata.resolution and on whether a video reference is included. See the live rate in the Model Square.