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Continue a clip with Seedance 1.5 Pro: the last frame of your video opens a new 4 to 12 second segment, and you get back one file with the original and the continuation joined, at 480p, 720p or 1080p.

From $0.011/s

Workbench

Send a request

Quickstart

Examples use the selected endpoint’s public parameter definitions. Replace the API key and example media, then send the request from your server.

SDKs & integrations
POSThttps://api.spicyapi.ai/api/v1/jobs/createTask

API authentication

Keep the API key in the server environment variable SPICY_API_KEY. Use Bearer authentication and Content-Type: application/json for JSON requests.

Authorization: Bearer $SPICY_API_KEY
# Generate the idempotency key once; reuse it when retrying after a lost response.
export SPICY_IDEMPOTENCY_KEY="${SPICY_IDEMPOTENCY_KEY:-$(uuidgen)}"
curl -X POST https://api.spicyapi.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $SPICY_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $SPICY_IDEMPOTENCY_KEY" \
  -d '{
  "model": "bytedance/seedance-1.5-pro/video-extend",
  "input": {
    "duration_seconds": 5,
    "generate_audio": true,
    "prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
    "resolution": "720p",
    "video_url": "https://example.com/reference.mp4"
  }
}'

# Copy data.taskId from the response into TASK_ID, then poll the status.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.spicyapi.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $SPICY_API_KEY"

Generated from this model’s input schema — the same one the API validates every request against.

Input parameters

Place these fields inside the request body’s input object. Names and types match the API. Do not assume a default when none is specified.

video_urlstringRequired

The clip to continue: MP4, MOV or WebM, up to 60 seconds. Its final frame becomes the opening frame of the new segment, so cut it on a clean, sharp frame. The source is not billed. The new segment is framed to the supported aspect ratio closest to your clip (21:9, 16:9, 4:3, 1:1, 3:4 or 9:16).

Default
Not specified
Constraints
minLength:1
format:"uri"
contentMediaType:["video/mp4","video/webm","video/quicktime"]
promptstringRequired

Required. What happens next: the action that follows, the camera move and the sound. The opening frame already fixes the subject and the set, so spend the words on motion. With camera_fixed on, keep every described movement inside the frame.

Default
Not specified
Constraints
minLength:3
seedintegerOptional

Integer from 0 to 2147483647; omit it and each run draws its own. Hold it fixed while you change one thing at a time; it keeps the starting noise, not the clip frame for frame. Available at 480p and 720p; a 1080p request that sets it is refused. No effect on price.

Default
Not specified
Constraints
minimum:0
maximum:2147483647
camera_fixedbooleanOptional

Locks the camera during the new segment, false by default. Set to true and the frame holds still while the subject moves within it; leave it false for a push, pan or tilt and say so in the prompt. No effect on price.

Default
false
generate_audiobooleanOptionalAffects price

On by default and priced in a higher tier; switch it off for a silent segment. Your source keeps its own sound either way; when one side is silent, the joined file is padded with silence.

Default
true
duration_secondsintegerOptionalAffects price

Length of the new segment in whole seconds, 4 to 12, defaulting to 5, and the billed quantity. Your source is added on top and is not billed. Confirm the motion at 4 or 5 seconds before going longer.

Default
5
Constraints
minimum:4
maximum:12
resolutionstringOptionalAffects price

Size of the new segment: 480p, 720p or 1080p, default 720p. Match your source: it only sets the quality of the new segment, and a lower setting makes the new part look softer than the original. The joined file keeps your clip’s framing with no black bars; to line the seam up, the picture may be trimmed or adjusted by a few percent at the edges. If the model returns a noticeably different shape, the new segment is scaled to fill your frame and centered, cropping what spills over. It sets the price.

Default
"720p"
Allowed values
"480p""720p""1080p"
last_image_urlstringOptional

Optional target end frame: the new segment lands on this picture instead of ending wherever the model chooses. Give it the same proportions as the last frame of your clip. Available at 480p and 720p; a 1080p request that sets it is refused. No effect on price.

Default
Not specified
Constraints
contentMediaType:["image/jpeg","image/png","image/webp","image/gif"]

Track the task

HTTP 202 means the task was accepted, not completed. Save the returned taskId and query that task. Do not create another task while waiting for its result.

Accepted response
HTTP/1.1 202 Accepted
Location: /api/v1/jobs/recordInfo?taskId=job_01k3m8x9q2z4v7n5p6r8s0t1w3

{
  "code": 200,
  "msg": "success",
  "request_id": "req_example_create",
  "data": {
    "taskId": "job_01k3m8x9q2z4v7n5p6r8s0t1w3",
    "state": "queued",
    "estimatedCost": "0.750000"
  }
}

The accepted response includes the estimate so your app can show the same amount in task history and billing.

Read the job
curl --get "https://api.spicyapi.ai/api/v1/jobs/recordInfo" \
  --data-urlencode "taskId=$TASK_ID" \
  -H "Authorization: Bearer $SPICY_API_KEY"

Start polling at about 2 seconds and gradually increase the interval. Stop at a terminal state. After a connection failure, query the original taskId. Retry creation only with the original idempotency key and body.

Or let the callback find you
import { verifyWebhook } from "@spicyapi/sdk";

// express.raw keeps the bytes we signed; express.json never matches.
app.post("/hooks/spicy", express.raw({ type: "application/json" }), (req, res) => {
  const { payload } = verifyWebhook({
    rawBody: req.body,
    timestamp: req.header("X-Webhook-Timestamp"),
    signature: req.header("X-Webhook-Signature"),
    payloadVersion: Number(req.header("X-Webhook-Payload-Version")),
    secret: process.env.SPICY_WEBHOOK_SECRET,
  });
  res.status(200).end();
  void handleFinishedTask(payload);
});

Pass callBackUrl when you create the task and the finished record is POSTed to you — no polling loop at all. Every delivery carries X-Webhook-Timestamp, X-Webhook-Signature and X-Webhook-Payload-Version. The signature is a base64 HMAC-SHA256 over taskId.timestamp.sha256(body), so it must be checked against the raw bytes: parsing the JSON and re-serialising it changes them and the check will fail. Failed deliveries are retried, so the same taskId can arrive twice — make the handler idempotent. Answer 2xx first and do the work afterwards; a slow handler is treated as a failed delivery.

Read the result

Consume output only when state is succeeded. On failure, use errorCode, errorMessage and request_id to investigate. Example costs and states do not represent an actual bill.

Completed response example
{
  "code": 200,
  "msg": "success",
  "request_id": "req_example_record",
  "data": {
    "taskId": "job_01k3m8x9q2z4v7n5p6r8s0t1w3",
    "model": "bytedance/seedance-1.5-pro/video-extend",
    "state": "succeeded",
    "output": {
      "assets": [
        {
          "key": "tasks/2026/08/28/job_01k3m8x9q2z4v7n5p6r8s0t1w3/3f7a1c9e5b2d48f0a6c1e3d5b7f9a1c3.mp4",
          "mime": "video/mp4",
          "url": "https://example.r2.cloudflarestorage.com/results/job_01k3m8x9q2z4v7n5p6r8s0t1w3/result.mp4?X-Amz-Signature=SIGNATURE_FROM_RESPONSE",
          "expiresAt": "2026-08-28T12:20:08.000Z"
        }
      ]
    },
    "cost": "0.750000",
    "settled": true,
    "createdAt": "2026-08-28T12:00:00Z",
    "completedAt": "2026-08-28T12:00:30Z"
  }
}

For each available asset, open or download assets[].url directly without an API Authorization header. The signed URL expires at expiresAt; poll the task again to refresh it while the asset remains within its retention period. A pending or unavailable asset has no URL. Treat signed URLs as private.

SDKs & integrations

Use SpicyAPI in your app, terminal, AI assistant or visual workflow. Choose a setup guide below.

Use it in ComfyUI

Install the SpicyAPI nodes from ComfyUI Manager or with the command below, then search for Seedance 1.5 Pro · Video Extend on the canvas. The node has the same options as this page and shows its price before it runs.

cd ComfyUI/custom_nodes
git clone https://github.com/spicyapi-ai/comfyui-spicyapi