Kling-4.0 Reference to Video

curl --request POST \
  --url https://api.evolink.ai/v1/videos/generations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "kling-v4-reference-to-video",
  "prompt": "Keep the same motion style as <<<video_1>>> and replace the background with a snowy scene",
  "video_urls": [
    "https://example.com/reference.mp4"
  ],
  "duration": 5,
  "aspect_ratio": "16:9",
  "quality": "720p"
}
'

{
  "created": 1757169743,
  "id": "task-unified-1757169743-7cvnl5zw",
  "model": "kling-v4-reference-to-video",
  "object": "video.generation.task",
  "progress": 0,
  "status": "pending",
  "task_info": {
    "can_cancel": true,
    "estimated_time": 300,
    "video_duration": 9
  },
  "type": "video",
  "usage": {
    "billing_rule": "per_second",
    "credits_reserved": 53.38,
    "user_group": "default"
  }
}

{
  "error": {
    "code": "invalid_request",
    "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: kling-v4-reference-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"
  }
}

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": "kling-v4-reference-to-video",
  "prompt": "Keep the same motion style as <<<video_1>>> and replace the background with a snowy scene",
  "video_urls": [
    "https://example.com/reference.mp4"
  ],
  "duration": 5,
  "aspect_ratio": "16:9",
  "quality": "720p"
}
'

{
  "created": 1757169743,
  "id": "task-unified-1757169743-7cvnl5zw",
  "model": "kling-v4-reference-to-video",
  "object": "video.generation.task",
  "progress": 0,
  "status": "pending",
  "task_info": {
    "can_cancel": true,
    "estimated_time": 300,
    "video_duration": 9
  },
  "type": "video",
  "usage": {
    "billing_rule": "per_second",
    "credits_reserved": 53.38,
    "user_group": "default"
  }
}

{
  "error": {
    "code": "invalid_request",
    "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: kling-v4-reference-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"
  }
}

Authorizations

Authorization

string

header

required

All APIs require Bearer Token authentication

Get API Key:

Visit API Key Management Page to get your API Key

Add to request header:

Authorization: Bearer YOUR_API_KEY

Body

application/json

model

enum<string>

default:kling-v4-reference-to-video

required

Video generation model name

Available options:

kling-v4-reference-to-video

Example:

"kling-v4-reference-to-video"

prompt

string

required

Text prompt, up to 2500 characters

Reference syntax: Use <<<xxx>>> in the prompt to reference images and videos, for example: The person from <<<image_1>>> walks down the street following the camera movement in <<<video_1>>>

Maximum string length: 2500

Example:

"The person from <<<image_1>>> walks down the street following the camera movement in <<<video_1>>>"

video_urls

string<uri>[]

Reference video URL array, up to 5 clips, corresponding in order to <<<video_1>>>, <<<video_2>>>, etc. in the prompt

Video requirements:

Formats: MP4 / MOV
Size: ≤ 200MB per clip
Duration: ≥ 3 seconds per clip, ≤ 30 seconds in total
Dimensions: width and height from 720px to 2160px
Frame rate: 24fps to 60fps
Video URLs must be directly accessible by the server

Maximum array length: 5

Example:

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

image_urls

string<uri>[]

Reference image URL array (style, scene, or subject references), corresponding in order to <<<image_1>>>, <<<image_2>>>, etc. in the prompt

Constraints: Up to 10 images Note: Image URLs must be directly accessible by the server or trigger a direct download when accessed

Maximum array length: 10

Example:

["https://example.com/character.jpg"]

duration

integer

default:5

Video duration in seconds, from 3 to 30

Required range: 3 <= x <= 30

Example:

5

aspect_ratio

enum<string>

default:16:9

Video aspect ratio

Options:

16:9: Landscape
9:16: Portrait
1:1: Square
21:9: Ultrawide

Available options:

16:9,

9:16,

1:1,

21:9

Example:

"16:9"

quality

enum<string>

default:720p

Resolution tier

Options:

720p: Standard 720P
1080p: High quality 1080P

Available options:

720p,

1080p

Example:

"720p"

callback_url

string<uri>

HTTPS callback URL for task completion

Callback Timing:

Triggered when task is completed, failed, or cancelled
Sent after billing confirmation

Security Restrictions:

HTTPS protocol only
Internal 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
Maximum 3 retries after failure (at 1/2/4 seconds after failure)
Callback response format is consistent with task query API
2xx status code is considered successful, other codes trigger retry

Example:

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

Response

Video generation task created successfully

created

integer

Task creation timestamp

Example:

1757169743

string

Task ID

Example:

"task-unified-1757169743-7cvnl5zw"

model

string

Actual model name used

Example:

"kling-v4-reference-to-video"

object

enum<string>

Task type

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>

Task output type

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

Kling-4.0 Reference to Video

Authorizations

All APIs require Bearer Token authentication

Body

Response