Seedance 2.5 API

Complete API reference for Seedance 2.5 video generation models by ByteDance.

Model Variants

This API supports three model variants:

Quick Comparison

Supported Aspect Ratios

Text-to-Video and Reference-to-Video support:

21:9, 16:9, 9:16, 1:1, 4:3, 3:4

Image-to-Video does not support the aspect_ratio parameter.

Resolution Options

Seedance 2.5 Text to Video

Endpoint

POST /api/v1/video/task

Request Parameters

Required

Optional

Example Request

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const response = await fetch('https://api.flaq.ai/api/v1/video/task', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    model_name: 'seedance-v2.5-text-to-video',
    prompt: 'A golden retriever running through a sunlit meadow',
    resolution: '720p',
    duration: 8,
    aspect_ratio: '16:9',
    sound: true
  })
});

const { data } = await response.json();
const taskId = data.task_id;

Seedance 2.5 Image to Video

Request Parameters

Required

Optional

Do not include aspect_ratio in Image-to-Video requests. This model does not support that parameter.

Example Request

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{
  model_name: 'seedance-v2.5-image-to-video',
  image_url: 'https://example.com/first-frame.jpg',
  image_end_url: 'https://example.com/last-frame.jpg',
  prompt: 'Camera slowly pulls back to reveal the full landscape',
  resolution: '720p',
  duration: 8,
  sound: true
}

Seedance 2.5 Reference to Video

Request Parameters

Required

Reference Media

@ (AT) Reference Placeholders

The @ (AT) reference feature links reference media to the prompt through numbered <<<...>>> placeholders. Numbering starts at 1 independently for each media type and follows the order of the corresponding array:

For example, if the first image is a character reference and the second image is a scene reference, use <<<image_1>>> for the character and <<<image_2>>> for the scene in prompt. Each placeholder must point to an item that exists in its corresponding array.

Optional

Example Request

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{
  model_name: 'seedance-v2.5-reference-to-video',
  prompt: 'Use image one for the subject, video one for the movement, and audio one for the atmosphere',
  resolution: '720p',
  duration: 8,
  aspect_ratio: '16:9',
  sound: true,
  images: ['https://example.com/subject-reference.jpg'],
  videos: ['https://example.com/motion-reference.mp4'],
  audios: ['https://example.com/atmosphere-reference.mp3']
}

@ (AT) Reference-to-Video Request Example

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{
  model_name: 'seedance-v2.5-reference-to-video',
  prompt: 'Place the explorer from <<<image_1>>> in the environment from <<<image_2>>>, following the camera movement in <<<video_1>>> and speaking with the reference voice from <<<audio_1>>>',
  resolution: '720p',
  duration: 10,
  aspect_ratio: '16:9',
  sound: true,
  images: [
    'https://example.com/explorer-reference.jpg',
    'https://example.com/environment-reference.png'
  ],
  videos: ['https://example.com/camera-movement-reference.mp4'],
  audios: ['https://example.com/voice-reference.mp3']
}

Response Format

Initial Response

All models return a task_id for polling:

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{
  "code": 0,
  "message": "success",
  "data": {
    "task_id": "{task_id}",
    "response_url": "https://api.flaq.ai/api/v1/video/{task_id}",
    "task_status": "submitted"
  }
}

Polling Response

Poll GET /api/v1/video/{taskId} to check status:

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{
  "code": 0,
  "message": "success",
  "data": {
    "task_id": "{task_id}",
    "response_url": "https://api.flaq.ai/api/v1/video/{task_id}",
    "task_status": "succeed",
    "task_status_msg": null,
    "task_result": {
      "videos": [
        {
          "url": "https://example.com/generated-video.mp4"
        }
      ]
    }
  }
}

Status Values

• submitted: Task accepted and waiting to be processed
• processing: Video generation in progress
• succeed: Video generation completed
• failed: Video generation failed

Processing Time

Processing time varies by duration, resolution, and current queue conditions.

Poll every 5-10 seconds to check status.

Best Practices

1. Required Parameters: Always provide resolution and duration, and provide aspect_ratio for Text-to-Video and Reference-to-Video
2. Image-to-Video Ratio: Do not send aspect_ratio for Image-to-Video requests
3. Reference Videos: Reference-to-Video requires at least one video; each video and the combined video duration must stay within the documented limits
4. Reference Images: Images are optional when reference videos are provided; when used, submit 1-30 supported image URLs
5. Reference Audio: Keep every audio clip within 2-30 seconds and 15 MB, with a combined duration of no more than 30 seconds
6. Reference Ordering: Keep images, videos, and audios in intentional order and refer to them consistently in the prompt
7. Sound: Omit sound to use its default value of true, or set it to false to disable generated sound