curl --request POST \
  --url https://api.evolink.ai/v1/videos/generations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "seedance-2.5-flash-text-to-video",
  "prompt": "A macro lens focuses on a green glass frog on a leaf. The focus gradually shifts from its smooth skin to its completely transparent abdomen, where a bright red heart is beating powerfully and rhythmically.",
  "duration": 8,
  "quality": "720p",
  "aspect_ratio": "16:9",
  "generate_audio": true,
  "content_filter": true
}
'

{
  "created": 1761313744,
  "id": "task-unified-1774857405-abc123",
  "model": "seedance-2.5-flash-text-to-video",
  "object": "video.generation.task",
  "progress": 0,
  "status": "pending",
  "task_info": {
    "can_cancel": false,
    "estimated_time": 165,
    "video_duration": 8
  },
  "type": "video",
  "usage": {
    "billing_rule": "per_second",
    "credits_reserved": 50,
    "user_group": "default"
  }
}

{
  "error": {
    "code": "invalid_parameter",
    "message": "Invalid request parameters",
    "type": "invalid_request_error"
  }
}

{
  "error": {
    "code": "unauthorized",
    "message": "Invalid or expired token",
    "type": "authentication_error"
  }
}

{
  "error": {
    "code": "insufficient_quota",
    "message": "Insufficient quota. Please top up your account.",
    "type": "insufficient_quota"
  }
}

{
  "error": {
    "code": "model_access_denied",
    "message": "Token does not have access to model: seedance-2.5-flash-text-to-video",
    "type": "invalid_request_error"
  }
}

{
  "error": {
    "code": "rate_limit_exceeded",
    "message": "Too many requests, please try again later",
    "type": "rate_limit_error"
  }
}

{
  "error": {
    "code": "internal_error",
    "message": "Internal server error",
    "type": "api_error"
  }
}

{
  "error": {
    "code": "<string>",
    "message": "<string>",
    "type": "<string>"
  }
}

Seedance 2.5 Flash

Seedance 2.5 Flash Complete Parameter Guide

Complete parameter reference for Seedance 2.5 Flash. Use model to select a model in this folder. Required fields, input requirements, and billing rules are listed for each mode.

Draft limitation: Seedance 2.5 Flash does not support draft: true or draft-to-final conversion.

Text-to-video web search: model_params.web_search: true cannot be combined with content_filter: false; sending both returns a 400 parameter error. Keep content_filter: true (the default) when web search is needed.

Model ID	Mode	Required fields (excluding model)
`seedance-2.5-flash-text-to-video`	Text-to-Video	`prompt`
`seedance-2.5-flash-image-to-video`	Image-to-Video	`prompt`, `image_urls`
`seedance-2.5-flash-reference-to-video`	Reference-to-Video	`prompt`
`seedance-2.5-flash-video-edit`	Video Edit	`prompt`, `video_urls`
`seedance-2.5-flash-video-extend`	Video Extend	`prompt`, `video_urls`

Text-to-Video

Generate videos from text prompts, supports web search for enhanced timeliness

Image-to-Video

Input 1 image for first-frame video generation, input 2 images for first-last-frame video generation, the model determines automatically

Reference-to-Video

Generate video from a text prompt with optional reference images (0–10), videos (0–5), and audio clips (0–5). References may be omitted entirely, and audio-only reference input is supported.
Best suited for generating new footage: images, videos, and audio act as style, subject, camera-movement, and soundtrack references
To rewrite or continue an existing video, switch to Video Edit / Video Extend: once this model’s prompt carries an editing or extension intent, the request is validated as an edit / extend task — it is accepted without an error and the task only fails while it runs

Video Edit

Video editing on an input video — replace subjects, add/remove objects, restyle or repaint regions
Describe the change directly in the prompt, e.g. “Remove all passers-by in @video1, keep only the main character”
Input the video to edit (required) + optional reference images (0–10) + reference videos (up to 5 in total) + reference audio (0–5)

Video Extend

Extend an input video forward or backward
Prompt must state the extension intent (e.g. “Extend @video1 backward, the character walks out of the frame”)
Input the video to extend (required) + optional reference images (0–10) + reference videos (up to 5 in total) + reference audio (0–5)
Now supports AIGC realistic human materials
Asynchronous processing mode, use the returned task ID to query status
Generated video links are valid for 24 hours, please save them promptly

POST

videos

generations

curl --request POST \
  --url https://api.evolink.ai/v1/videos/generations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "seedance-2.5-flash-text-to-video",
  "prompt": "A macro lens focuses on a green glass frog on a leaf. The focus gradually shifts from its smooth skin to its completely transparent abdomen, where a bright red heart is beating powerfully and rhythmically.",
  "duration": 8,
  "quality": "720p",
  "aspect_ratio": "16:9",
  "generate_audio": true,
  "content_filter": true
}
'

{
  "created": 1761313744,
  "id": "task-unified-1774857405-abc123",
  "model": "seedance-2.5-flash-text-to-video",
  "object": "video.generation.task",
  "progress": 0,
  "status": "pending",
  "task_info": {
    "can_cancel": false,
    "estimated_time": 165,
    "video_duration": 8
  },
  "type": "video",
  "usage": {
    "billing_rule": "per_second",
    "credits_reserved": 50,
    "user_group": "default"
  }
}

{
  "error": {
    "code": "invalid_parameter",
    "message": "Invalid request parameters",
    "type": "invalid_request_error"
  }
}

{
  "error": {
    "code": "unauthorized",
    "message": "Invalid or expired token",
    "type": "authentication_error"
  }
}

{
  "error": {
    "code": "insufficient_quota",
    "message": "Insufficient quota. Please top up your account.",
    "type": "insufficient_quota"
  }
}

{
  "error": {
    "code": "model_access_denied",
    "message": "Token does not have access to model: seedance-2.5-flash-text-to-video",
    "type": "invalid_request_error"
  }
}

{
  "error": {
    "code": "rate_limit_exceeded",
    "message": "Too many requests, please try again later",
    "type": "rate_limit_error"
  }
}

{
  "error": {
    "code": "internal_error",
    "message": "Internal server error",
    "type": "api_error"
  }
}

{
  "error": {
    "code": "<string>",
    "message": "<string>",
    "type": "<string>"
  }
}

Authorizations

Authorization

string

header

required

##All endpoints require Bearer Token authentication##

Get API Key:

Visit the API Key Management Page to obtain your API Key

Add to request header:

Authorization: Bearer YOUR_API_KEY

Body

application/json

This page combines the parameters of all modes. Required fields, accepted values, and defaults depend on the selected model; differences are listed by mode below.

model

enum<string>

required

Video generation model name

Model ID	Mode	Required fields (excluding model)
`seedance-2.5-flash-text-to-video`	Text-to-Video	`prompt`
`seedance-2.5-flash-image-to-video`	Image-to-Video	`prompt`, `image_urls`
`seedance-2.5-flash-reference-to-video`	Reference-to-Video	`prompt`
`seedance-2.5-flash-video-edit`	Video Edit	`prompt`, `video_urls`
`seedance-2.5-flash-video-extend`	Video Extend	`prompt`, `video_urls`

Available options:

seedance-2.5-flash-text-to-video,

seedance-2.5-flash-image-to-video,

seedance-2.5-flash-reference-to-video,

seedance-2.5-flash-video-edit,

seedance-2.5-flash-video-extend

Example:

"seedance-2.5-flash-text-to-video"

prompt

string

required

Text-to-Video

Text prompt describing the desired video. Supports both Chinese and English, recommended no more than 500 characters for Chinese or 1000 words for English. Maximum prompt length: 10000 tokens

Note:

This model is text-to-video only and does not support image_urls, video_urls, or audio_urls input

Image-to-Video

Text prompt describing the desired video. Supports both Chinese and English, recommended no more than 500 characters for Chinese or 1000 words for English. Maximum prompt length: 10000 tokens

Note:

This model does not support video_urls or audio_urls input

Reference-to-Video

Text prompt describing the desired video. Supports both Chinese and English, recommended no more than 500 characters for Chinese. Maximum prompt length: 10000 tokens

Details:

When referring to input materials in the prompt, prefer explicit tags such as @image1, @video1, and @audio1 instead of relying only on natural-language references such as "image 1", "video 1", or "audio 1"
Tag numbers follow the order of the corresponding URL array and start at 1: the first image_urls item is @image1, the first video_urls item is @video1, and the first audio_urls item is @audio1
Natural-language numbering may still be understood, but explicit tags provide a clearer mapping between each material and its intended use

Avoid being classified as an edit / extend task:

The task type is inferred from the prompt intent: wording such as "edit the video", "add", "remove / delete", "change / replace" is treated as video editing; wording such as "extend forward / backward", "continue" is treated as video extension
Once classified as either task, aspect_ratio must be adaptive, and for video editing duration must be -1; otherwise the request is accepted without an error and the task later turns failed with error code InvalidParameter.TaskTypeConstraint. The pre-authorized quota is refunded, but the waiting time is wasted
If you really need editing / extension, use seedance-2.5-flash-video-edit or seedance-2.5-flash-video-extend instead: parameters are validated at submission, so invalid values return an immediate synchronous error
For pure reference generation, rephrase words like "replace" or "remove" descriptively, e.g. "the shot features ..." or "rendered in the style of @image1"

Video Edit

Text prompt describing the desired edit. Supports both Chinese and English, recommended no more than 500 characters for Chinese. Maximum prompt length: 10000 tokens

Details:

The prompt must state the editing intent, e.g., "Edit the video: remove the background music of @video1"
You can use natural language to specify the purpose of each material, e.g., "replace the character in @video1 with the person in @image1"
The model will automatically understand the correspondence between material numbers and their intended uses

Video Extend

Text prompt describing the desired extension. Supports both Chinese and English, recommended no more than 500 characters for Chinese. Maximum prompt length: 10000 tokens

Details:

The prompt must state the extension intent, e.g., "Extend @video1 backward, the character walks out of the frame"
You can use natural language to specify the purpose of each material, e.g., "extend @video1 forward following the style of @image1"
The model will automatically understand the correspondence between material numbers and their intended uses

Example:

"A macro lens focuses on a green glass frog on a leaf. The focus gradually shifts from its smooth skin to its completely transparent abdomen, where a bright red heart is beating powerfully and rhythmically."

image_urls

string<uri>[]

Applies only to: Image-to-Video, Reference-to-Video, Video Edit, Video Extend

Image-to-Video

Image URL array, 1–2 images

Image count and behavior:

Image Count	Behavior	Role
1 image	First-frame image-to-video	Automatically set as `first_frame`
2 images	First-last-frame image-to-video	1st image → `first_frame`, 2nd image → `last_frame`

Image requirements:

Supported formats: .jpeg, .png, .webp
Aspect ratio (width/height): 0.4 ~ 2.5
Width/height pixels: 300 ~ 6000 px
Max size per image: 30MB
Total request body size must not exceed 64MB
When providing first and last frames, both images can be identical. If aspect ratios differ, the first frame takes priority and the last frame will be automatically cropped to fit
Image URLs must be directly accessible by the server

Media addresses: Publicly accessible HTTP(S) URLs and asset:// media IDs accessible to the selected upstream account are supported.

Reference-to-Video

Reference image URL array, optional; 1–10 images when provided

Optional references: image_urls, video_urls, and audio_urls may all be omitted. Providing only audio_urls is also supported.

Role description:

Media Type	Role	Typical Usage
Image	`reference_image`	Style reference, product image, first/last frame (specified via prompt)

Image requirements:

Supported formats: .jpeg, .png, .webp
Aspect ratio (width/height): 0.4 ~ 2.5
Width/height pixels: 300 ~ 6000 px
Max size per image: 30MB
Total request body size must not exceed 64MB, do not use Base64 encoding
Image URLs must be directly accessible by the server

Media addresses: Publicly accessible HTTP(S) URLs and asset:// media IDs accessible to the selected upstream account are supported.

Video Edit

Reference image URL array, optional; 1–10 images when provided

Requirement: video_urls is required for this model; images are optional supplementary references.

Role description:

Media Type	Role	Typical Usage
Image	`reference_image`	Style reference, product image, replacement subject (specified via prompt)

Image requirements:

Supported formats: .jpeg, .png, .webp
Aspect ratio (width/height): 0.4 ~ 2.5
Width/height pixels: 300 ~ 6000 px
Max size per image: 30MB
Total request body size must not exceed 64MB, do not use Base64 encoding
Image URLs must be directly accessible by the server

Media addresses: Publicly accessible HTTP(S) URLs and asset:// media IDs accessible to the selected upstream account are supported.

Video Extend

Reference image URL array, optional; 1–10 images when provided

Requirement: video_urls is required for this model; images are optional supplementary references.

Role description:

Media Type	Role	Typical Usage
Image	`reference_image`	Style reference, product image, scene reference (specified via prompt)

Image requirements:

Supported formats: .jpeg, .png, .webp
Aspect ratio (width/height): 0.4 ~ 2.5
Width/height pixels: 300 ~ 6000 px
Max size per image: 30MB
Total request body size must not exceed 64MB, do not use Base64 encoding
Image URLs must be directly accessible by the server

Media addresses: Publicly accessible HTTP(S) URLs and asset:// media IDs accessible to the selected upstream account are supported.

Maximum array length: 10

Example:

["https://example.com/first-frame.jpg"]

video_urls

string<uri>[]

Applies only to: Reference-to-Video, Video Edit, Video Extend

Reference-to-Video

Reference video URL array, optional; 1–5 videos when provided

Optional references: image_urls, video_urls, and audio_urls may all be omitted. Providing only audio_urls is also supported.

Role description:

Media Type	Role	Typical Usage
Video	`reference_video`	Camera movement reference, motion reference, original video for editing/extension

Video requirements:

Supported formats: .mp4, .mov
Resolution: 480p, 720p, 1080p, 4K
Duration per video: 2 ~ 30 seconds, max 5 videos, total duration of all videos ≤ 30 seconds
Aspect ratio (width/height): 0.4 ~ 2.5
Width/height pixels: 300 ~ 6000 px
Frame pixels (width × height): 409,600 ~ 8,295,044 (e.g., 640×640 ~ 3326×2494)
Max size per video: 200MB
Frame rate: 24 ~ 60 FPS
Total request body size must not exceed 64MB, do not use Base64 encoding
Specific codec, resolution, and other media validity checks are performed by the model
Using video references will increase costs (input video duration is counted in billing)
Video URLs must be directly accessible by the server

Media addresses: Publicly accessible HTTP(S) URLs and asset:// media IDs accessible to the selected upstream account are supported.

Video Edit

Input video URL array, required; 1–5 videos

Requirement: At least 1 video required — the video to edit. The first video is the video being edited; additional videos serve as references.

Role description:

Media Type	Role	Typical Usage
Video	`reference_video`	The video to edit (first video), camera movement or motion reference (additional videos)

Video requirements:

Supported formats: .mp4, .mov
Resolution: 480p, 720p, 1080p, 4K
Duration per video: 4 ~ 30 seconds (the first video is the edit target), max 5 videos, total duration of all videos ≤ 30 seconds
Aspect ratio (width/height): 0.4 ~ 2.5
Width/height pixels: 300 ~ 6000 px
Frame pixels (width × height): 409,600 ~ 8,295,044 (e.g., 640×640 ~ 3326×2494)
Max size per video: 200MB
Frame rate: 24 ~ 60 FPS
Total request body size must not exceed 64MB, do not use Base64 encoding
Specific codec, resolution, and other media validity checks are performed by the model
Using video references will increase costs (input video duration is counted in billing)
Video URLs must be directly accessible by the server

Media addresses: Publicly accessible HTTP(S) URLs and asset:// media IDs accessible to the selected upstream account are supported.

Video Extend

Input video URL array, required; 1–5 videos

Requirement: At least 1 video required — the video to extend. The first video is the video being extended; additional videos serve as references.

Role description:

Media Type	Role	Typical Usage
Video	`reference_video`	The video to extend (first video), camera movement or motion reference (additional videos)

Video requirements:

Supported formats: .mp4, .mov
Resolution: 480p, 720p, 1080p, 4K
Duration per video: 2 ~ 30 seconds, max 5 videos, total duration of all videos ≤ 30 seconds
Aspect ratio (width/height): 0.4 ~ 2.5
Width/height pixels: 300 ~ 6000 px
Frame pixels (width × height): 409,600 ~ 8,295,044 (e.g., 640×640 ~ 3326×2494)
Max size per video: 200MB
Frame rate: 24 ~ 60 FPS
Total request body size must not exceed 64MB, do not use Base64 encoding
Specific codec, resolution, and other media validity checks are performed by the model
Using video references will increase costs (input video duration is counted in billing)
Video URLs must be directly accessible by the server

Media addresses: Publicly accessible HTTP(S) URLs and asset:// media IDs accessible to the selected upstream account are supported.

Maximum array length: 5

Example:

["https://example.com/reference.mp4"]

audio_urls

string<uri>[]

Applies only to: Reference-to-Video, Video Edit, Video Extend

Reference-to-Video

Reference audio URL array, optional; 1–5 clips when provided

Optional references: image_urls, video_urls, and audio_urls may all be omitted. Providing only audio_urls is also supported.

Role description:

Media Type	Role	Typical Usage
Audio	`reference_audio`	Background music, sound effects, voice/dialogue reference

Audio requirements:

Supported formats: .wav, .mp3
Duration per clip: 2 ~ 30 seconds, max 5 clips, total duration of all audio ≤ 30 seconds
Max size per clip: 15MB
Total request body size must not exceed 64MB, do not use Base64 encoding
Audio URLs must be directly accessible by the server

Media addresses: Publicly accessible HTTP(S) URLs and asset:// media IDs accessible to the selected upstream account are supported.

Video Edit / Video Extend

Reference audio URL array, optional; 1–5 clips when provided

Requirement: video_urls is required for this model; audio clips are optional supplementary references.

Role description:

Media Type	Role	Typical Usage
Audio	`reference_audio`	Background music, sound effects, voice/dialogue reference

Audio requirements:

Supported formats: .wav, .mp3
Duration per clip: 2 ~ 30 seconds, max 5 clips, total duration of all audio ≤ 30 seconds
Max size per clip: 15MB
Total request body size must not exceed 64MB, do not use Base64 encoding
Audio URLs must be directly accessible by the server

Media addresses: Publicly accessible HTTP(S) URLs and asset:// media IDs accessible to the selected upstream account are supported.

Maximum array length: 5

Example:

["https://example.com/bgm.mp3"]

duration

Text-to-Video / Image-to-Video

Video duration (seconds), defaults to 5 seconds

Details:

Supports any integer value between 4–30 seconds
-1: automatic duration, the model picks a length within 4–30 seconds and billing follows the actual output length
Duration directly affects billing

Reference-to-Video

Output video duration (seconds), defaults to 5 seconds

Details:

Supports any integer value between 4–30 seconds
-1: automatic duration, the model picks a length within 4–30 seconds and billing follows the actual output length
Duration directly affects billing

If the prompt is classified as a video edit task, only -1 is accepted; an explicit number of seconds makes the task fail later, with no error at submission

Video Edit

Output video duration (seconds), defaults to -1

Details:

Only -1 is supported: the output length follows the input video (may be up to 0.4s shorter)
Custom durations are rejected
Duration directly affects billing

Video Extend

Output video duration (seconds), defaults to 5 seconds

Details:

Supports any integer value between 4–30 seconds
-1: automatic duration, settled by actual output length
Duration directly affects billing

Available options:

-1

Example:

8

quality

enum<string>

default:720p

Video resolution, defaults to 720p

Options:

480p: Lower clarity, lower cost
720p: Standard clarity, this is the default

Available options:

480p,

720p

Example:

"720p"

aspect_ratio

enum<string>

default:adaptive

Text-to-Video

Video aspect ratio, defaults to adaptive

Options:

16:9 (landscape), 9:16 (portrait), 1:1 (square), 4:3, 3:4, 21:9 (ultrawide)
adaptive: The model intelligently selects the best aspect ratio based on the prompt

Pixel values per resolution:

Aspect Ratio	480p	720p
16:9	854×480	1280×720
4:3	752×560	1112×834
1:1	640×640	960×960
3:4	560×752	834×1112
9:16	480×854	720×1280
21:9	992×432	1470×630

Image-to-Video

Video aspect ratio, image-to-video only supports adaptive

Options:

adaptive: Automatically selects the closest aspect ratio based on the first-frame image proportions, the only value this model accepts
Fixed ratios such as 16:9 or 9:16 cannot be specified for this model

Reference-to-Video

Video aspect ratio, defaults to adaptive

Options:

16:9 (landscape), 9:16 (portrait), 1:1 (square), 4:3, 3:4, 21:9 (ultrawide)
adaptive: Determined based on prompt intent, priority: video > image > prompt

Pixel values per resolution:

Aspect Ratio	480p	720p
16:9	854×480	1280×720
4:3	752×560	1112×834
1:1	640×640	960×960
3:4	560×752	834×1112
9:16	480×854	720×1280
21:9	992×432	1470×630

If the prompt is classified as a video edit / extend task, only adaptive is accepted; a fixed ratio makes the task fail later, with no error at submission

Video Edit / Video Extend

Video aspect ratio, defaults to adaptive

Options:

adaptive: the output ratio follows the first input video, the only value this model accepts
Fixed ratios such as 16:9 or 9:16 are rejected

Available options:

16:9,

9:16,

1:1,

4:3,

3:4,

21:9,

adaptive

Example:

"16:9"

generate_audio

boolean

default:true

Text-to-Video

Whether to generate synchronized audio, defaults to true

Options:

true: Video includes synchronized audio (voice, sound effects, background music) at no additional charge. It is recommended to place dialogue within double quotes to optimize audio generation
false: Output silent video

Image-to-Video / Reference-to-Video / Video Edit / Video Extend

Whether to generate synchronized audio, defaults to true

Options:

true: Video includes synchronized audio at no additional charge
false: Output silent video

Example:

true

content_filter

boolean

default:true

Content filter, enabled by default true

Options:

true: Standard content safety check, this is the default
false: Relaxes content restrictions, billed at +10% (1.1x). Illegal and prohibited content is always enforced regardless of this setting

Mutually exclusive with web search:

content_filter: false and model_params.web_search: true cannot be used together; sending both returns a 400 parameter error
Keep content_filter: true (the default) when web search is needed

Example:

true

output_format

enum<string>

default:mp4

Output container format, defaults to mp4

Options:

mp4: H.264 encoding with the best compatibility and standard color precision, this is the default
mov: H.264 + yuv444p chroma sampling + PCM audio for higher color fidelity, recommended for color grading, keying and compositing workflows. Browser inline playback may not support it; download and play with VLC / mpv / ffplay. No extra charge

Available options:

mp4,

mov

Example:

"mp4"

model_params

object

Applies only to: Text-to-Video

Model extension parameters

Show child attributes

callback_url

string<uri>

HTTPS callback URL for task completion

Callback timing:

Triggered when the task is completed or failed
Sent after billing confirmation is complete

Security restrictions:

Only HTTPS protocol is supported
Callbacks to private IP addresses are prohibited (127.0.0.1, 10.x.x.x, 172.16-31.x.x, 192.168.x.x, etc.)
URL length must not exceed 2048 characters

Callback mechanism:

Timeout: 10 seconds
Up to 3 retries after failure (at 1/2/4 seconds after failure respectively)
Callback response body format is consistent with the task query endpoint response format
A 2xx status code is considered successful; other status codes trigger retries

Example:

"https://your-domain.com/webhooks/video-task-completed"

Response

Video generation task created successfully

created

integer

Task creation timestamp

Example:

1761313744

string

Task ID

Example:

"task-unified-1774857405-abc123"

model

string

Actual model name used

Example:

"seedance-2.5-flash-text-to-video"

object

enum<string>

Specific type of the task

Available options:

video.generation.task

progress

integer

Task progress percentage (0-100)

Required range: 0 <= x <= 100

Example:

0

status

enum<string>

Task status

Available options:

pending,

processing,

completed,

failed

Example:

"pending"

task_info

object

Video task details

Show child attributes

type

enum<string>

Output type of the task

Available options:

text,

image,

audio,

video

Example:

"video"

usage

object

Usage and billing information

Show child attributes

Image Series

Video Series

Audio Series

Text Series

Account Management

Task Management

File Management

Seedance 2.5 Flash Complete Parameter Guide

Text-to-Video

Image-to-Video

Reference-to-Video

Video Edit

Video Extend

Authorizations

Body

Response