Seedance 2.0 Series Guide

Updated: 2026-07-29

Use the Seedance 2.0 series through UniAll. New integrations should use one of the three stable public model IDs and select the resolution and generation capability through request parameters.

1. Choose a Model

Public Model	Supported Resolutions	Recommended Use
`seedance2.0`	`480p`, `720p`, `1080p`, `4k`	Full capabilities with quality prioritized
`seedance2.0-fast`	`480p`, `720p`	Faster generation
`seedance2.0-mini`	`480p`, `720p`	Lightweight and speed-focused tasks

All three models support:

text-to-video;
single-image-to-video;
first-and-last-frame generation;
multimodal image, video, and audio references;
video editing and extension;
generated audio, watermarks, and random seeds;
web search for text-only requests;
returning the generated video's last frame;
existing asset:// asset IDs.

2. Endpoints and Authentication

Use the OpenAI-compatible video task endpoints:

POST /v1/videos
GET  /v1/videos/{task_id}
GET  /v1/videos/{task_id}/content

Request headers:

Authorization: Bearer sk-***
Content-Type: application/json

Use this value for {BASE_URL} in the examples:

https://api.uniall.ai

The following compatibility endpoints remain available:

POST /v1/videos/generations
GET  /v1/videos/generations/{task_id}

POST /v1/video/generations
GET  /v1/video/generations/{task_id}

New integrations should use /v1/videos consistently.

3. Common Parameters

Parameter	Type	Required	Description
`model`	string	Yes	One of the three public models, or a fixed-resolution model ID during the compatibility period.
`prompt`	string	Conditional	Video prompt. When using `content[]`, include at least one `type=text` item instead.
`resolution`	string	Yes for new public models	Output resolution from the selected model's supported values.
`size`	string	No	Compatibility alias for `resolution`.
`duration`	integer/string	Yes	Output duration from `4` to `15` seconds. The compatible value `auto` is accepted, but an explicit integer is recommended.
`aspect_ratio`	string	No	`auto`, `21:9`, `16:9`, `4:3`, `3:2`, `2:3`, `1:1`, `3:4`, or `9:16`.
`ratio`	string	No	Compatibility alias for `aspect_ratio`; `adaptive` is equivalent to `auto`.
`content`	object[]	No	Recommended multimodal input format described in the next section.
`operation`	string	Required for specific capabilities	`reference_to_video`, `edit_video`, or `extend_video`.
`generate_audio`	boolean	No	Whether to generate a video with audio.
`watermark`	boolean	No	Whether to add a watermark.
`seed`	integer	No	Random seed.
`return_last_frame`	boolean	No	Whether to return a last-frame URL in the completed result.
`tools`	object[]	No	Currently supports only `[{"type":"web_search"}]`.

Compatibility rules:

resolution and size must match when both are present.
aspect_ratio and ratio must express the same ratio when both are present.
ratio: "adaptive" is equivalent to aspect_ratio: "auto".
operation, generate_audio, watermark, seed, return_last_frame, and tools may also be placed inside extra_body. Do not repeat the same parameter at the top level and in extra_body.
draft, frames, camera_fixed, and service_tier: "flex" are outside the current public contract.

4. Multimodal `content[]` Format

Use content[] for complex inputs:

{
  "content": [
    {
      "type": "text",
      "text": "Video prompt"
    },
    {
      "type": "image_url",
      "image_url": {
        "url": "https://example.com/image.png"
      },
      "role": "reference_image"
    },
    {
      "type": "video_url",
      "video_url": {
        "url": "https://example.com/video.mp4"
      },
      "role": "reference_video"
    },
    {
      "type": "audio_url",
      "audio_url": {
        "url": "https://example.com/audio.mp3"
      },
      "role": "reference_audio"
    }
  ]
}

Supported types and roles:

`type`	`role`	Meaning
`text`	None	One or more prompt items.
`image_url`	`image`	Input image for single-image-to-video.
`image_url`	`reference_image`	Reference image.
`image_url`	`first_frame`	First-frame image.
`image_url`	`last_frame`	Last-frame image.
`video_url`	`source_video`	Source video for editing or extension.
`video_url`	`reference_video`	Reference video.
`audio_url`	`reference_audio`	Reference audio.

Input constraints:

content[] must contain at least one non-empty text item.
Use no more than 9 images, 3 videos, and 3 audio files.
first_frame and last_frame must be provided together, with one image for each role.
First-and-last-frame mode cannot include videos, audio, or other images.
Do not mix the image and reference_image roles in one request.
Use no more than one source_video.
Reference audio requires at least one image or video. Audio-only and text-plus-audio requests are not accepted.
With multiple reference assets, use @Image1, @Video1, and @Audio1 in the prompt to identify assets by order.

Simple requests remain compatible with image, images, last_image, video, videos, and audios. Use content[] for new capabilities and multimodal combinations so each input role is explicit.

5. Request Examples

5.1 Text-to-Video

curl -X POST "{BASE_URL}/v1/videos" \
  -H "Authorization: Bearer sk-***" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance2.0",
    "prompt": "A futuristic city street after rain, neon reflections, and a slow cinematic camera push forward.",
    "resolution": "1080p",
    "duration": 5,
    "ratio": "16:9",
    "generate_audio": true
  }'

5.2 Single-Image-to-Video

curl -X POST "{BASE_URL}/v1/videos" \
  -H "Authorization: Bearer sk-***" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance2.0-fast",
    "resolution": "720p",
    "duration": 6,
    "content": [
      {
        "type": "text",
        "text": "The person turns naturally toward the camera, clothing moves gently in the wind, and identity remains consistent."
      },
      {
        "type": "image_url",
        "image_url": {
          "url": "https://example.com/person.png"
        },
        "role": "image"
      }
    ]
  }'

5.3 First-and-Last-Frame Video

curl -X POST "{BASE_URL}/v1/videos" \
  -H "Authorization: Bearer sk-***" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance2.0",
    "resolution": "720p",
    "duration": 6,
    "content": [
      {
        "type": "text",
        "text": "Transition naturally from day to night with continuous motion and stable building structure."
      },
      {
        "type": "image_url",
        "image_url": {
          "url": "https://example.com/first.png"
        },
        "role": "first_frame"
      },
      {
        "type": "image_url",
        "image_url": {
          "url": "https://example.com/last.png"
        },
        "role": "last_frame"
      }
    ]
  }'

5.4 Multimodal Reference-to-Video

curl -X POST "{BASE_URL}/v1/videos" \
  -H "Authorization: Bearer sk-***" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance2.0-mini",
    "resolution": "720p",
    "duration": 8,
    "operation": "reference_to_video",
    "content": [
      {
        "type": "text",
        "text": "Show the product from @Image1 with the camera motion from @Video1 and the rhythm from @Audio1."
      },
      {
        "type": "image_url",
        "image_url": {
          "url": "https://example.com/product.png"
        },
        "role": "reference_image"
      },
      {
        "type": "video_url",
        "video_url": {
          "url": "https://example.com/motion.mp4"
        },
        "role": "reference_video"
      },
      {
        "type": "audio_url",
        "audio_url": {
          "url": "https://example.com/music.mp3"
        },
        "role": "reference_audio"
      }
    ]
  }'

5.5 Video Editing

curl -X POST "{BASE_URL}/v1/videos" \
  -H "Authorization: Bearer sk-***" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance2.0",
    "resolution": "720p",
    "duration": 6,
    "operation": "edit_video",
    "content": [
      {
        "type": "text",
        "text": "Replace the background with a neon street at night while preserving the person's motion and identity."
      },
      {
        "type": "video_url",
        "video_url": {
          "url": "https://example.com/source.mp4"
        },
        "role": "source_video"
      },
      {
        "type": "image_url",
        "image_url": {
          "url": "https://example.com/style.png"
        },
        "role": "reference_image"
      }
    ]
  }'

5.6 Video Extension

curl -X POST "{BASE_URL}/v1/videos" \
  -H "Authorization: Bearer sk-***" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance2.0-fast",
    "resolution": "720p",
    "duration": 5,
    "operation": "extend_video",
    "content": [
      {
        "type": "text",
        "text": "Continue the camera motion as the person walks forward, preserving the lighting and scene."
      },
      {
        "type": "video_url",
        "video_url": {
          "url": "https://example.com/source.mp4"
        },
        "role": "source_video"
      }
    ]
  }'

5.7 Text-Only Web Search

Web search works only with text input. Do not include images, video, or audio in the same request.

curl -X POST "{BASE_URL}/v1/videos" \
  -H "Authorization: Bearer sk-***" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance2.0-mini",
    "prompt": "Create a concise news video from today's publicly available technology news without showing brand logos.",
    "resolution": "720p",
    "duration": 5,
    "tools": [
      {
        "type": "web_search"
      }
    ]
  }'

web_search allows the model to retrieve public information, but it does not guarantee that every generation will perform a search.

5.8 Return the Last Frame

curl -X POST "{BASE_URL}/v1/videos" \
  -H "Authorization: Bearer sk-***" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance2.0",
    "prompt": "A paper boat slowly stops beside a stone bridge, with a stable final frame.",
    "resolution": "720p",
    "duration": 5,
    "return_last_frame": true
  }'

When the task completes, the last frame is returned as result.last_frame_url and is not mixed into the video outputs array.

5.9 Use A Managed Material

Create and query reusable inputs through the Seedance 2.0 Material Library. When the material reaches status=available, replace a regular media URL with the returned uri:

{
  "type": "video_url",
  "video_url": {
    "url": "asset://asset-xxxxxxxxxxxxx"
  },
  "role": "source_video"
}

Use the URI only in the matching structured image, video, or audio field. Do not put it in the prompt. UniAll.ai verifies the current user's ownership, material status, and expiry before creating the video task.

6. Task Status And Result

A successful create request returns an asynchronous task:

{
  "id": "task_xxxxxxxxxxxxx",
  "task_id": "task_xxxxxxxxxxxxx",
  "object": "video.generation.job",
  "model": "seedance2.0",
  "status": "queued",
  "progress": 0,
  "created_at": 1784640000
}

After creation, save id or task_id, then poll GET /v1/videos/{task_id} until the task reaches completed or failed. See Video Generation Overview for the shared polling interval, status fields, error contract, result URL, and authenticated download flow.

When a Seedance request produces a last frame, the completed response may also include result.last_frame_url.

7. Fixed-Resolution Model Compatibility

Existing clients may continue using fixed-resolution model IDs:

Model Series	Compatible Model IDs
Standard	`seedance2.0-480p`, `seedance2.0-720p`, `seedance2.0-1080p`, `seedance2.0-4k`
Fast	`seedance2.0-fast-480p`, `seedance2.0-fast-720p`
Mini	`seedance2.0-mini-480p`, `seedance2.0-mini-720p`

The following earlier IDs also remain compatible:

seedance2.0-video-480p
seedance2.0-video-720p
seedance2.0-fast-video-480p
seedance2.0-fast-video-720p

Fixed-resolution model IDs determine the resolution and do not require an additional resolution field. They support the same parameters and capabilities as the corresponding public model. If resolution or size is still present, its value must match the resolution in the model ID.

New projects should migrate to the three public model IDs so output resolution can be changed through a request parameter.

8. Common Errors

Scenario	Result	Fix
New public model is missing `resolution`/`size`	HTTP `400`	Pass a supported resolution.
`resolution` and `size` differ	HTTP `400`	Pass one field, or make both values identical.
`aspect_ratio` and `ratio` conflict	HTTP `400`	Pass one field, or make both express the same ratio.
Missing `duration`	HTTP `400`	Pass an integer from `4` to `15`.
`content[]` has no text item	HTTP `400`	Add a non-empty `type=text` item.
First and last frames are not paired	HTTP `400`	Pass both `first_frame` and `last_frame`.
Audio-only or text-plus-audio input	HTTP `400`	Add at least one image or video.
Web-search request contains media	HTTP `400`	Keep only text input in a search request.
Too many images, videos, or audio files	HTTP `400`	Keep the counts at or below 9, 3, and 3.
`draft`, `frames`, `camera_fixed`, or `service_tier=flex` is used	HTTP `400`	Remove the unsupported parameter.

For safety-review, media-format, or parameter errors, fix the input and create a new task instead of repeatedly submitting the same invalid request.

1. Choose a Model​

2. Endpoints and Authentication​

3. Common Parameters​

4. Multimodal content[] Format​

5. Request Examples​

5.1 Text-to-Video​

5.2 Single-Image-to-Video​

5.3 First-and-Last-Frame Video​

5.4 Multimodal Reference-to-Video​

5.5 Video Editing​

5.6 Video Extension​

5.7 Text-Only Web Search​

5.8 Return the Last Frame​

5.9 Use A Managed Material​

6. Task Status And Result​

7. Fixed-Resolution Model Compatibility​

8. Common Errors​

9. Related Pages​