Docs - sjolt model API documentation

ByteDance

Seedance 2.0

A multimodal video generation model for text prompts, first-frame animation, and reference-guided production clips.

Image to Video FastModel docs

POST/sjolt-ai/v1/bytedance/seedance-2.0/fast/image-to-video

Seedance 2.0 Fast Image To Video API

Endpoint:

http

POST /sjolt-ai/v1/bytedance/seedance-2.0/fast/image-to-video

Generate a video from a required first-frame image and prompt, with an optional ending frame.

Authentication

Include your sjolt API key on every request:

http

Authorization: Bearer $SJOLT_API_KEY

Create a task

bash

curl /sjolt-ai/v1/bytedance/seedance-2.0/fast/image-to-video \
  -H "Authorization: Bearer $SJOLT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "input": {
    "prompt": "A cinematic product launch shot with slow camera movement, realistic lighting, synchronized ambient sound, and no text overlays.",
    "resolution": "720p",
    "duration": "8",
    "aspect_ratio": "16:9",
    "seed": -1,
    "image_url": "https://example.com/first-frame.png",
    "end_image_url": "https://example.com/last-frame.png"
  },
  "webhook": "https://example.com/webhook"
}'

Request body:

json

{
  "input": {
    "prompt": "A cinematic product launch shot with slow camera movement, realistic lighting, synchronized ambient sound, and no text overlays.",
    "resolution": "720p",
    "duration": "8",
    "aspect_ratio": "16:9",
    "seed": -1,
    "image_url": "https://example.com/first-frame.png",
    "end_image_url": "https://example.com/last-frame.png"
  },
  "webhook": "https://example.com/webhook"
}

Successful response:

json

{
  "success": true,
  "data": {
    "task_id": "gen_7nz4q8x2"
  }
}

Query task status and results

bash

curl /sjolt-ai/v1/tasks/{task_id} \
  -H "Authorization: Bearer $SJOLT_API_KEY"

Successful response:

json

{
  "success": true,
  "data": {
    "task_id": "gen_7nz4q8x2",
    "status": 1,
    "output_urls": [
      "https://file.sjolt.ai/output/seedance-2-0-result.mp4"
    ],
    "error": null,
    "create_time": "2026-06-30T12:00:00.000Z",
    "update_time": "2026-06-30T12:04:20.000Z"
  }
}

Status values:

Status	Meaning
`0`	Running
`1`	Succeeded. Read generated MP4 URLs from `data.output_urls`.
`2`	Failed. Read the failure reason from `data.error`.

Parameters

Parameter	Required	Type	Supported values	Description
`prompt`	Yes	string	Non-empty text	Describes the video to generate.
`image_url`	Yes	string	Public image URL	Opening frame used to drive the video.
`end_image_url`	No	string	Public image URL	Optional ending frame for first/last-frame generation.
`resolution`	No	string	`480p`, `720p`	Output resolution. Defaults to `720p` when omitted.
`duration`	No	string or number	an integer from `4` to `15` seconds	Output duration. Defaults to `5` seconds when omitted.
`aspect_ratio`	No	string	`auto`, `21:9`, `16:9`, `4:3`, `1:1`, `3:4`, `9:16`	Output frame ratio. `auto` lets the service choose.
`seed`	No	integer	Any integer, commonly `-1` for random	Controls reproducibility when supported by the backend.
`webhook`	No	string	Callback URL string	Top-level callback URL. See Webhook callback.

Notes

Send generation parameters under the top-level input object. Optional webhook is a top-level request field alongside input.
Do not send an internal provider field. sjolt selects the backend provider internally.
Only use parameters listed for this selected variant. Unsupported parameters may be ignored or rejected by validation.
For reference-to-video variants, billable duration is based on input reference video duration plus output video duration.

Webhook callback

If you include a top-level webhook URL in the create-task request, sjolt sends a best-effort POST to that URL when the task reaches a terminal state.

http

Content-Type: application/json

Succeeded callback:

json

{
  "task_id": "gen_7nz4q8x2",
  "status": "succeeded",
  "output": {
    "output_url_list": [
      "https://file.sjolt.ai/output/result.png"
    ]
  },
  "error": null
}

Failed callback:

json

{
  "task_id": "gen_7nz4q8x2",
  "status": "failed",
  "output": {
    "output_url_list": []
  },
  "error": "failure reason"
}

Webhook delivery is best-effort. Query /sjolt-ai/v1/tasks/{task_id} for final status and result URLs.