Seedance 2.0 Fast is the speed edition of ByteDance's Seedance 2.0, out since February 2026. It takes exactly the same request as the full model, so everything you learn here carries over, but it stops at 720p. For social posts, previews and ad variants that live on phones, that ceiling rarely matters, and you get results sooner for less.
What you can make
- A preview of a shot before you spend more on the full model.
- Vertical 720p clips for Reels, Shorts and TikTok.
- Dozens of ad variants that test different hooks.
- Cheap trial runs of prompts and reference combinations.
Settings that matter
- Length: 4 to 15 seconds, set explicitly. Automatic duration (
-1) is not offered on Fast. - Resolution: 480p or 720p. No 1080p and no 4K.
- Aspect ratio: 16:9 unless you change it, so pick 9:16 for vertical platforms.
- Inputs: text, images, a start and end frame, or reference clips and audio, as on the full Seedance 2.0.
- Sound: on by default. Send
generate_audio: falsewhen your own music goes on top. - Upgrade path: a draft that works can be rerendered on Seedance 2.0 by changing only the model id.
Starter prompt
Vertical 9:16, handheld close-up: a barista pours latte art in slow motion, milk swirls into a heart, cafe chatter and the hiss of the steam wandChange the action and the background sounds; keep the shot description at the start so framing stays consistent across variants.
Questions
What do I pay for a Seedance 2.0 Fast clip?
from $0.124 per second. The API returns estimated_cost and Studio shows the amount before you start; a failed clip is free.
Can I still get 1080p later?
Yes. Keep the same request and switch the model to Seedance 2.0, which goes up to 4K.
Fast or Mini for cheap clips?
Both top out at 720p. Fast has sound on by default; Seedance 2.0 Mini keeps it off. Check the Mini vs Fast comparison and the estimate for your settings.
Seedance 2.0 Fast in your code
curl https://kadraris.com/v1/generate?wait=60 \
-H "Authorization: Bearer $KADRARIS_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "seedance-2.0-fast",
"input": {
"prompt": "Tracking shot of a cyclist riding through an empty city street at dawn, long shadows, light fog, film look",
"aspect_ratio": "16:9",
"resolution": "720p",
"duration": 5
}
}'import os, time, requests
API = "https://kadraris.com/v1"
H = {"Authorization": f"Bearer {os.environ['KADRARIS_API_KEY']}"}
task = requests.post(f"{API}/generate", headers=H, json={
"model": "seedance-2.0-fast",
"input": {
"prompt": "Tracking shot of a cyclist riding through an empty city street at dawn, long shadows, light fog, film look",
"aspect_ratio": "16:9",
"resolution": "720p",
"duration": 5
}
}).json()
while task["status"] in ("queued", "running"):
time.sleep(3)
task = requests.get(f"{API}/tasks/{task['id']}", headers=H).json()
print(task["status"], task["cost"], [o["url"] for o in task["output"]])const API = "https://kadraris.com/v1";
const headers = { Authorization: `Bearer ${process.env.KADRARIS_API_KEY}`, "Content-Type": "application/json" };
let task = await (await fetch(`${API}/generate`, {
method: "POST",
headers,
body: JSON.stringify({
"model": "seedance-2.0-fast",
"input": {
"prompt": "Tracking shot of a cyclist riding through an empty city street at dawn, long shadows, light fog, film look",
"aspect_ratio": "16:9",
"resolution": "720p",
"duration": 5
}
}),
})).json();
while (task.status === "queued" || task.status === "running") {
await new Promise((r) => setTimeout(r, 3000));
task = await (await fetch(`${API}/tasks/${task.id}`, { headers })).json();
}
console.log(task.status, task.cost, task.output.map((o) => o.url));Input fields
| Parameter | Type | Allowed | Default |
|---|---|---|---|
prompt * | string | ≤ 20000 chars | |
aspect_ratio | string | 16:9 9:16 1:1 4:3 3:4 21:9 adaptive | 16:9 |
resolution | string | 480p 720p | 720p |
duration | integer | 4-15 | 5 |
generate_audio | boolean | true | |
image_url | string | ||
end_image_url | string | ||
image_urls | array | max 9 | |
video_urls | array | max 3 | |
audio_urls | array | max 3 |
Fetch this list as JSON with GET /v1/models/seedance-2.0-fast.