Seedance 2.5

Seedance 2.5 is ByteDance's newest video generation model (Dreamina Seedance 2.5). Send the official ModelArk task body, keep the returned task ID, and read the finished video from the task. Images, videos and audio go in content as URLs.

Model IDs

See the model page for current prices.

Quick example

curl https://api.seedrouter.ai/v1/contents/generations/tasks \
  -H "Authorization: Bearer $SEEDROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "dreamina-seedance-2-5",
    "content": [{"type": "text", "text": "A red paper boat drifts across a calm pond at sunrise, slow dolly-in"}],
    "resolution": "720p",
    "ratio": "16:9",
    "duration": 5,
    "generate_audio": true
  }'

Endpoint

POST https://api.seedrouter.ai/v1/contents/generations/tasks

The body is the official ModelArk "create a video generation task" request. If you already call ModelArk, change only the base URL to https://api.seedrouter.ai/v1 and the API key. The response is {"id": "task_..."}, not the finished video. Keep API keys in server-side code.

Parameters

content items

Unknown fields are rejected. Not supported: seed, callback_url (poll the task instead), draft and draft_task, tools, and the 1.x-only frames and camera_fixed. Tasks cannot be cancelled or deleted.

Modes

The mode follows from the content items; there is no mode parameter.

First-frame modes cannot be combined with reference items. With several images or any other media, every image needs a role.

Reference example

curl https://api.seedrouter.ai/v1/contents/generations/tasks \
  -H "Authorization: Bearer $SEEDROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "dreamina-seedance-2-5",
    "content": [
      {"type": "text", "text": "The character from the image walks through the market in the video, same camera move"},
      {"type": "image_url", "image_url": {"url": "https://example.com/character.png"}, "role": "reference_image"},
      {"type": "video_url", "video_url": {"url": "https://example.com/market.mp4"}, "role": "reference_video"}
    ],
    "ratio": "adaptive",
    "duration": 8
  }'

Replace the example URLs with your own accessible files.

Media inputs

This API accepts URL references only. Base64, data: URLs, asset:// IDs and multipart uploads are not accepted. The Playground uploads selected files to storage before submitting their URLs.

Media must be public HTTP(S) URLs and meet the model's official limits:

Reference images and videos that contain real human faces are not supported by the model.

Media is checked when the task starts, before any generation. A task whose media breaks one of these limits ends as failed with invalid_request_error and a message naming the rule, for example The request was rejected: content reference videos must total at most 15 seconds., and is not charged. A file that cannot be read at that point is passed to the model, which accepts or rejects it; a failed task is not charged either way.

Pricing dimensions

Check the model pricing section for current rates. Seedance 2.5 bills video tokens, the official unit:

video tokens = (output seconds + reference video seconds) × width × height × 24 / 1024

The rate per million tokens depends on the output resolution and on whether the request includes a reference video; a request with a reference video uses a lower rate for all of its tokens. Text, image and audio inputs are not billed. At 16:9, one second is 9,607.5 tokens at 480p (854×480), 21,600 at 720p, 48,600 at 1080p.

The charge follows the tokens the finished video reports (usage.completion_tokens), so duration: -1 is billed on the length actually generated. Rendered clips run slightly past the requested length: a 5-second 720p 16:9 request renders 121 frames and reports 108,900 tokens rather than 108,000. View final charges in your account usage history. Failed and expired tasks are not charged.

Output schema

Submission returns the task ID:

{"id": "task_..."}

Get the task

curl https://api.seedrouter.ai/v1/contents/generations/tasks/YOUR_TASK_ID \
  -H "Authorization: Bearer $SEEDROUTER_API_KEY"

Poll every 10–20 seconds until status is succeeded, failed or expired. A network timeout while polling does not mean generation failed: keep the task ID and resume checking it. Do not create another task to check progress.

Complete polling example

Run this after the Python submission example above.

import time

deadline = time.monotonic() + 1800
while time.monotonic() < deadline:
    result = requests.get(
        f"https://api.seedrouter.ai/v1/contents/generations/tasks/{task_id}",
        headers={"Authorization": f"Bearer {os.environ['SEEDROUTER_API_KEY']}"},
        timeout=30,
    )
    result.raise_for_status()
    task = result.json()
    if task["status"] == "succeeded":
        print(task["content"]["video_url"])
        break
    if task["status"] in ("failed", "expired"):
        raise RuntimeError(task["error"]["message"])
    time.sleep(15)
else:
    raise TimeoutError(f"Still waiting. Resume polling task {task_id}.")

Succeeded task

{
  "id": "task_...",
  "model": "dreamina-seedance-2-5",
  "status": "succeeded",
  "content": {
    "video_url": "https://static.seedrouter.ai/media/tasks/task_example/0.mp4",
    "last_frame_url": "https://static.seedrouter.ai/media/tasks/task_example/last_frame/0.jpg"
  },
  "usage": {"completion_tokens": 108900, "total_tokens": 108900},
  "seed": 42,
  "resolution": "720p",
  "ratio": "16:9",
  "duration": 5,
  "framespersecond": 24,
  "generate_audio": true,
  "draft": false,
  "output_format": "mp4",
  "service_tier": "default",
  "execution_expires_after": 172800,
  "priority": 0,
  "created_at": 1790321515,
  "updated_at": 1790321652
}

Video URLs are hosted on our storage. Save the file to your own storage when you need a durable copy.

List tasks

curl "https://api.seedrouter.ai/v1/contents/generations/tasks?page_num=1&page_size=20&filter.status=succeeded" \
  -H "Authorization: Bearer $SEEDROUTER_API_KEY"

Returns {"total": N, "items": [...]} with task objects from the last 7 days, newest first. page_num and page_size are 1–500 (defaults 1 and 20). Filters: filter.status, filter.model, filter.task_ids (repeatable) and filter.service_tier.

Errors

Requests rejected before a task is created return an HTTP error with an error object and are not charged. A task that fails after acceptance returns HTTP 200 when queried, with status: "failed" (or "expired") and an error object. Output withheld by content filtering fails with content_policy_violation; a task that runs past execution_expires_after ends as expired with task_expired.

See the shared error catalog for codes, HTTP statuses, and retry guidance.

{
  "id": "task_...",
  "model": "dreamina-seedance-2-5",
  "status": "failed",
  "error": {
    "code": 60001,
    "message": "The request was rejected by the content policy. Please revise the prompt or input images."
  }
}

If submission itself times out, check your task list before submitting again: the first request may have been accepted.

Tips

• Describe the subject, the action, the camera move, and the lighting in full sentences.
• Draft at 480p with a short duration, then render the keeper at a higher resolution.
• Chain shots with return_last_frame: use the returned frame as the next task's first_frame.
• To edit footage, set omni_reference_task_type to edit and describe only what should change.

Related

• Seedance 2.5 Playground and pricing
• Download OpenAPI
• Copyable Markdown