Seedance 2.0 / 2.5 Video Generation API Reference

curl -X POST "https://api.apiyi.com/seedance/api/v3/contents/generations/tasks" \
  -H "Authorization: Bearer sk-your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "doubao-seedance-2-0-fast-260128",
    "content": [
      {"type": "text", "text": "Drone shot flying over an autumn valley, golden forests and a winding river, cinematic"}
    ],
    "resolution": "720p",
    "ratio": "16:9",
    "duration": 5,
    "generate_audio": false
  }'
# Returns {"id":"cgt-2026xxxx-xxxxx"} — poll the query endpoint with this id

import time
import requests

BASE = "https://api.apiyi.com/seedance/api/v3/contents/generations/tasks"
HEADERS = {
    "Authorization": "Bearer sk-your-api-key",
    "Content-Type": "application/json",
    # Required: the gateway's gzip header does not match the actual encoding.
    # Without this you may get gzip decode errors, a truncated non-JSON body
    # (e.g. id":"cgt-xxx"} with the leading {" lost), or intermittent 400s
    "Accept-Encoding": "identity",
}

# 1. Create the task
body = {
    "model": "doubao-seedance-2-0-fast-260128",
    "content": [
        {"type": "text", "text": "Waves crashing on rocks at sunset, slow motion, serene mood"}
    ],
    "resolution": "720p",
    "ratio": "16:9",
    "duration": 5,
    # "generate_audio": False,  # defaults to True; uncomment for silent video
    # "seed": 12345,            # fix the seed for similar, reproducible results
}
task_id = requests.post(BASE, json=body, headers=HEADERS, timeout=60).json()["id"]
print("task_id:", task_id)

# 2. Poll until a terminal state (succeeded / failed / expired)
while True:
    time.sleep(20)
    task = requests.get(f"{BASE}/{task_id}", headers=HEADERS, timeout=30).json()
    status = task.get("status")
    print("status:", status)
    if status in ("succeeded", "failed", "expired"):
        break

# 3. Download the video (the URL expires in 24 h — copy it out immediately)
if status == "succeeded":
    video_url = task["content"]["video_url"]   # note: under content, not top-level
    print("tokens:", task["usage"]["completion_tokens"])
    with requests.get(video_url, stream=True, timeout=300) as r:
        r.raise_for_status()
        with open(f"{task_id}.mp4", "wb") as f:
            for chunk in r.iter_content(chunk_size=1 << 20):
                f.write(chunk)
    print(f"saved {task_id}.mp4")
else:
    print("task did not succeed:", task.get("error"))

# First + last frame: 2 images, roles required; mutually exclusive with reference mode
body_first_last = {
    "model": "doubao-seedance-2-0-260128",
    "content": [
        {"type": "text", "text": "Smooth transition from the first frame to the last, slow camera move"},
        {"type": "image_url", "image_url": {"url": "https://example.com/first.jpg"},
         "role": "first_frame"},
        {"type": "image_url", "image_url": {"url": "https://example.com/last.jpg"},
         "role": "last_frame"},
    ],
    "resolution": "720p",
    "ratio": "adaptive",   # match the first frame's ratio to avoid cropping
    "duration": 5,
}

# Multi-modal reference: 0-9 reference images + 0-3 reference videos + 0-3 reference audios
# (at least 1 image or 1 video); can create / edit / extend videos
body_reference = {
    "model": "doubao-seedance-2-0-260128",
    "content": [
        {"type": "text", "text": "Using the reference character and style, the character walks down a rainy street at night"},
        {"type": "image_url", "image_url": {"url": "https://example.com/character.png"},
         "role": "reference_image"},
        # {"type": "video_url", "video_url": {"url": "..."}, "role": "reference_video"},
        # {"type": "audio_url", "audio_url": {"url": "..."}, "role": "reference_audio"},
    ],
    "resolution": "720p",
    "ratio": "16:9",
    "duration": 5,
}
# Images also accept Base64 (data:image/png;base64,xxx) and platform asset IDs (asset://xxx)

# 2.5 shares the endpoint and request shape with 2.0 — only `model` changes.
# The four bodies below are capabilities unique to 2.5.

# 1. 30-second clip: 2.5 caps at 30 s (the 2.0 family caps at 15)
body_30s = {
    "model": "doubao-seedance-2-5-260628",
    "content": [{"type": "text", "text": "Drone shot flying over an autumn valley, morning mist drifting through the trees, one continuous take"}],
    "resolution": "720p",
    "ratio": "16:9",
    "duration": 30,        # Do not omit: on 2.5 the default is -1 and the model picks its own length
}

# 2. Video editing: ratio must be adaptive, duration must be -1, source video 4-30 s
body_edit = {
    "model": "doubao-seedance-2-5-260628",
    "content": [
        # The prompt needs an editing verb: add / remove / delete / change / replace
        {"type": "text", "text": "Add a few birds flying across @video1"},
        {"type": "video_url", "video_url": {"url": "https://example.com/source.mp4"},
         "role": "reference_video"},
    ],
    "resolution": "720p",
    "ratio": "adaptive",                    # Required; a concrete ratio returns a synchronous 400
    "duration": -1,                         # Required; a concrete duration returns a synchronous 400
    "omni_reference_task_type": "edit",     # Declare it to validate at submission time
    "output_format": "mov",                 # Optional: mov is recommended for post (some players cannot open it)
}

# 3. Video extension: ratio must be adaptive
body_extend = {
    "model": "doubao-seedance-2-5-260628",
    "content": [
        # The prompt needs an extension verb: extend / continue
        {"type": "text", "text": "Extend @video1 forward, camera keeps pushing in as the light fades"},
        {"type": "video_url", "video_url": {"url": "https://example.com/source.mp4"},
         "role": "reference_video"},
    ],
    "resolution": "720p",
    "ratio": "adaptive",
    "omni_reference_task_type": "extend",
}

# 4. Audio-only reference: unique to 2.5; the 2.0 family requires an image or video alongside audio
body_audio_only = {
    "model": "doubao-seedance-2-5-260628",
    "content": [
        {"type": "text", "text": "Abstract light and shadow pulsing to the rhythm of @audio1"},
        {"type": "audio_url", "audio_url": {"url": "https://example.com/track.mp3"},
         "role": "reference_audio"},
    ],
    "resolution": "720p",
    "ratio": "16:9",
    "duration": 5,
}
# Submission and polling are identical to the flow above.

const BASE = "https://api.apiyi.com/seedance/api/v3/contents/generations/tasks";
const HEADERS = {
  "Authorization": "Bearer sk-your-api-key",
  "Content-Type": "application/json",
};

// 1. Create the task
const { id } = await fetch(BASE, {
  method: "POST",
  headers: HEADERS,
  body: JSON.stringify({
    model: "doubao-seedance-2-0-fast-260128",
    content: [{ type: "text", text: "A mountain lake reflecting the starry sky, time-lapse" }],
    resolution: "720p",
    ratio: "9:16",        // portrait costs the same as landscape
    duration: 5,
  }),
}).then(r => r.json());
console.log("task_id:", id);

// 2. Poll until a terminal state
let task;
do {
  await new Promise(r => setTimeout(r, 20000));
  task = await fetch(`${BASE}/${id}`, { headers: HEADERS }).then(r => r.json());
  console.log("status:", task.status);
} while (!["succeeded", "failed", "expired"].includes(task.status));

// 3. The video link (expires in 24 h — re-host immediately)
if (task.status === "succeeded") console.log(task.content.video_url);

curl "https://api.apiyi.com/seedance/api/v3/contents/generations/tasks/cgt-2026xxxx-xxxxx" \
  -H "Authorization: Bearer sk-your-api-key"