Seedance 2 Fast

Generate 4–15 second videos at 480p or 720p, at a lower price than Seedance 2.0, from text, a first and last frame, or up to 9 images, 3 videos and 3 audio clips as references.

• Asynchronous: the create call returns a task ID; the video arrives when the task succeeds (usually a few minutes).
• Four ways in: text only, a first frame, a first and last frame, or reference images, videos and audio in any mix (audio needs at least one image or video beside it).
• 480p and 720p only, at a lower price than Seedance 2.0 at the same resolution.
• Sound is generated by default (generate_audio) and does not change the price.
• Billed by the size and length of the video, plus the length of any reference videos. A failed task costs nothing.

Opens this model in the API Explorer. Enter your BeatAPI API key to create a task: the call is real and is billed to your own balance.

Model IDs

Four Seedance models share this endpoint. The values below come straight from the gateway contract; only Seedance 2.5 accepts task_type, output_format and seed.

Endpoint and authentication

POST https://api.beatapi.io/v1/videos/tasks

Send the body as JSON with Content-Type: application/json. Idempotency-Key is optional: send a unique value (at most 255 characters) per logical request and reuse it only to retry that exact body. Within 24 hours a retry with the same key and body returns the first response again with Idempotent-Replayed: true; the same key with a different body returns 409 idempotency_conflict. Responses other than 2xx are not stored, so a retry after a 400 or 402 runs again.

How a request works

Input modes

Request parameters

The gateway also checks these combinations before creating the task:

• images cannot be combined with reference inputs

Input media limits

The gateway reads every input before the task is created and refuses one outside these limits with a 400 bad_request that names the input. Nothing is charged.

• Reference videos must be MP4 or MOV, at a public HTTPS link whose host answers byte-range requests. A clip whose length cannot be read is always refused, because its seconds are billed.
• Image size is checked when the host reports it. Use JPEG, PNG or WebP; a file the model cannot use fails the task after submission with bad_request, and the task is refunded.
• Limits are reported in the order length, sides, aspect ratio, pixels, frame rate and size. The message names the input by list and position, counting from 0 like the field errors: reference_videos[0] is 1.5 seconds long; this model takes reference video of 1.8 to 15 seconds.
• Lengths are measured with a 0.1-second tolerance. Sizes are checked only when the host reports them.
• Image and audio links are refused at create only when the host answers with a 4xx error or returns an empty file, for example images[1] could not be downloaded: the URL returned HTTP 404.; other problems with them surface after submission.
• A clip at 23.976 FPS counts as below 24 and is refused; re-export it at 24 FPS or higher.
• Have a local file? Upload it with POST /v1/files and pass the returned data.url.

Combination rules

These are checked when the task is created, in this order. A request that breaks one is refused with 400 bad_request and costs nothing.

Fields this model does not accept

Sending one of these is refused before anything is charged, instead of being ignored:

• Fields of other video models, such as seed, task_type, output_format (Seedance 2.5 only), watermark, quality, sound, multi_shots or character_orientation → field "seed" is not supported by model seedance-2-fast (with the field you sent).
• A name no BeatAPI video model uses → unknown field: <name>.

Estimating the price

The video tokens of a task are N = W × H × (24 × D + 1 + 24 × R) / 1024, where W × H is the frame size in pixels at the chosen resolution and aspect ratio (1280 × 720 for 720p at 16:9, 864 × 496 for 480p at 16:9), D is the output length in seconds and R the total length of the reference videos in seconds (0 without any). The price is N times the rate per million video tokens: about $5.575 without reference video and$3.315 with it, for 480p and 720p alike.

For example, 5 seconds at 720p and 16:9 without reference video is 1280 × 720 × 121 / 1024 = 108,900 tokens, about $0.607. The gateway measures the reference clips itself; you do not send their length. This is an estimate; usage on the task shows what was reserved and charged.

Request examples

curl --request POST \
  --url https://api.beatapi.io/v1/videos/tasks \
  --header "Authorization: Bearer $BEATAPI_API_KEY" \
  --header 'Content-Type: application/json' \
  --data '{
  "model": "seedance-2-fast",
  "prompt": "A fast handheld tracking shot through a rain-lit night market, neon reflections on wet stone, ambient crowd sound",
  "duration": 5,
  "aspect_ratio": "16:9",
  "resolution": "720p"
}'

Text to video

A 5-second 720p landscape clip with sound.

curl --request POST \
  --url https://api.beatapi.io/v1/videos/tasks \
  --header "Authorization: Bearer $BEATAPI_API_KEY" \
  --header 'Content-Type: application/json' \
  --data '{
  "model": "seedance-2-fast",
  "prompt": "A fast handheld tracking shot through a rain-lit night market, neon reflections on wet stone, ambient crowd sound",
  "duration": 5,
  "aspect_ratio": "16:9",
  "resolution": "720p"
}'

First frame

The video starts from the image.

curl --request POST \
  --url https://api.beatapi.io/v1/videos/tasks \
  --header "Authorization: Bearer $BEATAPI_API_KEY" \
  --header 'Content-Type: application/json' \
  --data '{
  "model": "seedance-2-fast",
  "prompt": "Animate the singer with a quick natural camera push-in",
  "images": [
    "https://media.beatapi.io/samples/neon-singer.png"
  ],
  "duration": 5,
  "resolution": "720p"
}'

First and last frame

The video moves from the first image to the second.

curl --request POST \
  --url https://api.beatapi.io/v1/videos/tasks \
  --header "Authorization: Bearer $BEATAPI_API_KEY" \
  --header 'Content-Type: application/json' \
  --data '{
  "model": "seedance-2-fast",
  "prompt": "The camera pushes in from the bottle on the table to the singer on a neon stage in one continuous move",
  "images": [
    "https://media.beatapi.io/samples/smart-bottle.png",
    "https://media.beatapi.io/samples/neon-singer.png"
  ],
  "duration": 6,
  "resolution": "720p"
}'

Image and audio references

A performance that follows a character image and a music clip.

curl --request POST \
  --url https://api.beatapi.io/v1/videos/tasks \
  --header "Authorization: Bearer $BEATAPI_API_KEY" \
  --header 'Content-Type: application/json' \
  --data '{
  "model": "seedance-2-fast",
  "prompt": "The singer from the first reference image performs on stage in time with the reference music, warm spotlights, slow orbiting camera",
  "reference_images": [
    "https://media.beatapi.io/samples/neon-singer.png"
  ],
  "reference_audios": [
    "https://media.beatapi.io/samples/neon-singer-preview.mp3"
  ],
  "duration": 8,
  "resolution": "720p"
}'

Image, video and audio references

Replace the video link with your own MP4 or MOV of 15 seconds or less. Every second of the reference video is billed (see Billing).

curl --request POST \
  --url https://api.beatapi.io/v1/videos/tasks \
  --header "Authorization: Bearer $BEATAPI_API_KEY" \
  --header 'Content-Type: application/json' \
  --data '{
  "model": "seedance-2-fast",
  "prompt": "A product film: the bottle from the first reference image on a turntable, camera movement like the first reference video, cut to the beat of the reference music",
  "reference_images": [
    "https://media.beatapi.io/samples/smart-bottle.png"
  ],
  "reference_videos": [
    "https://your-cdn.example.com/clips/source.mp4"
  ],
  "reference_audios": [
    "https://media.beatapi.io/samples/neon-singer-preview.mp3"
  ],
  "duration": 8,
  "resolution": "720p"
}'

Responses

Create a task (201)

The task object. output is null until the task succeeds. Fields marked “while running” disappear once the task finishes.

{
  "data": {
    "id": "task_7Qm2Xc9LpR4vT8sKa1Nf6YbH3eWdJ0uZ",
    "object": "task",
    "task_kind": "video",
    "capability_id": "seedance-2-fast",
    "capability_version": 1,
    "media_type": "video",
    "model": "seedance-2-fast",
    "status": "queued",
    "stage": "queued",
    "created_at": 1791993600,
    "updated_at": 1791993600,
    "completed_at": null,
    "poll_after_seconds": 8,
    "output": null,
    "usage": {
      "credits_reserved": 0.607155,
      "credits_settled": 0,
      "credits_refunded": 0,
      "credits_charged": 0.607155,
      "billable_duration_seconds": 5
    },
    "request_id": "req_5f0c2a9e4b7d4e31",
    "error_code": null,
    "error_message": null
  }
}

Finished task

GET /v1/tasks/{task_id} returns HTTP 200 with status: "succeeded" and the result in data.output.

{
  "data": {
    "id": "task_7Qm2Xc9LpR4vT8sKa1Nf6YbH3eWdJ0uZ",
    "object": "task",
    "task_kind": "video",
    "capability_id": "seedance-2-fast",
    "capability_version": 1,
    "media_type": "video",
    "model": "seedance-2-fast",
    "status": "succeeded",
    "stage": "succeeded",
    "created_at": 1791993600,
    "updated_at": 1791993690,
    "completed_at": 1791993690,
    "output": {
      "media": [
        {
          "type": "video",
          "url": "https://media.beatapi.io/outputs/task_7Qm2Xc9LpR4vT8sKa1Nf6YbH3eWdJ0uZ/0.mp4",
          "mime_type": "video/mp4"
        }
      ],
      "r2_url": "https://media.beatapi.io/outputs/task_7Qm2Xc9LpR4vT8sKa1Nf6YbH3eWdJ0uZ/0.mp4"
    },
    "usage": {
      "credits_reserved": 0.607155,
      "credits_settled": 0.607155,
      "credits_refunded": 0,
      "credits_charged": 0.607155,
      "billable_duration_seconds": 5
    },
    "request_id": "req_5f0c2a9e4b7d4e31",
    "error_code": null,
    "error_message": null
  }
}

Output fields

Failed task

A failed task is still HTTP 200 on GET /v1/tasks/{task_id}: the failure is in the body. The reservation is returned in full, so nothing is charged.

{
  "data": {
    "id": "task_7Qm2Xc9LpR4vT8sKa1Nf6YbH3eWdJ0uZ",
    "object": "task",
    "task_kind": "video",
    "capability_id": "seedance-2-fast",
    "capability_version": 1,
    "media_type": "video",
    "model": "seedance-2-fast",
    "status": "failed",
    "stage": "failed",
    "created_at": 1791993600,
    "updated_at": 1791993690,
    "completed_at": 1791993690,
    "output": null,
    "usage": {
      "credits_reserved": 0.607155,
      "credits_settled": 0,
      "credits_refunded": 0.607155,
      "credits_charged": 0,
      "billable_duration_seconds": 5
    },
    "retryable": true,
    "request_id": "req_5f0c2a9e4b7d4e31",
    "error_code": "processing_failed",
    "error_message": "The task failed during processing on our side. Retry; a failed task is refunded."
  }
}

Complete example

Create a task, wait for it with the server’s polling hint, and print the result URLs. Set BEATAPI_API_KEY in your environment and install requests.

import os
import time
import uuid
import requests
API = "https://api.beatapi.io"
HEADERS = {"Authorization": f"Bearer {os.environ['BEATAPI_API_KEY']}"}
def create_task(body: dict) -> dict:
    # One Idempotency-Key per logical request: a retry with the same key cannot create a second task.
    headers = {**HEADERS, "Idempotency-Key": str(uuid.uuid4())}
    for attempt in range(3):
        response = requests.post(f"{API}/v1/videos/tasks", headers=headers, json=body, timeout=60)
        if response.status_code in (429, 503) and attempt < 2:
            time.sleep(int(response.headers.get("Retry-After", 10)))
            continue
        break
    try:
        payload = response.json()
    except ValueError:  # an edge error page is not JSON
        response.raise_for_status()
        raise
    if not response.ok:
        error = payload["error"]
        raise RuntimeError(f"{response.status_code} {error['code']}: {error['message']} (request_id={error.get('request_id')})")
    return payload["data"]
def wait_for_task(task_id: str, timeout_seconds: int = 1800) -> dict:
    deadline = time.monotonic() + timeout_seconds
    while time.monotonic() < deadline:
        response = requests.get(f"{API}/v1/tasks/{task_id}", headers=HEADERS, timeout=30)
        if response.status_code == 429 or response.status_code >= 500:
            time.sleep(int(response.headers.get("Retry-After", 10)))
            continue
        response.raise_for_status()
        task = response.json()["data"]
        if task["status"] in ("succeeded", "failed"):
            return task
        time.sleep(task.get("poll_after_seconds", 5))
    raise TimeoutError(f"task {task_id} is still running; keep polling later")
task = create_task({
  "model": "seedance-2-fast",
  "prompt": "A fast handheld tracking shot through a rain-lit night market, neon reflections on wet stone, ambient crowd sound",
  "duration": 5,
  "aspect_ratio": "16:9",
  "resolution": "720p"
})
print("created", task["id"])
task = wait_for_task(task["id"])
if task["status"] == "failed":
    raise SystemExit(f"{task['error_code']}: {task['error_message']}")
for item in task["output"]["media"]:
    print(item["url"])

Billing

• The price follows the size and length of the video: more seconds, a higher resolution or a larger frame cost more. Sound does not change it; reference images and audio add nothing.
• Without reference video, a 16:9 clip costs about $0.056 (480p) or$0.120 (720p) per second. Other aspect ratios differ by a few percent.
• With reference_videos, the whole request moves to the lower “with video input” rate, and every second of reference video counts like a second of output: about $0.033 (480p) or$0.072 (720p) per second of output plus reference, at 16:9.
• The table below shows 8-second clips; its “with video input” rows include an 8-second reference video.
• The price is reserved when the task is created. With adaptive the reservation assumes the largest frame of the resolution. You pay the reservation, or the actual amount if the delivered video comes to more.
• A failed task, including one refused by moderation after submission, is refunded in full.

Current list prices, the same as on Pricing. An account with a negotiated discount pays less; data.usage on the task always shows the amount actually charged.

Common errors

HTTP errors at a glance

Errors before a task exists arrive as a non-2xx response, and nothing is charged. Branch on error.code or error.retryable; message names the problem. The full list and retry policy are on Errors.

{
  "error": {
    "code": "bad_request",
    "message": "\"prompt\" is required",
    "retryable": false,
    "request_id": "req_5f0c2a9e4b7d4e31"
  }
}