curl --request POST \
  --url https://api.modellix.ai/api/v1/google/veo-3.1-i2v \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "prompt": "The character waves and smiles at the camera",
  "image": "https://example.com/frame.jpg"
}
'

{
  "code": 0,
  "message": "success",
  "data": {
    "status": "pending",
    "task_id": "task-i2v001",
    "model_id": "google/veo-3.1-i2v",
    "get_result": {
      "method": "GET",
      "url": "https://api.modellix.ai/api/v1/tasks/task-i2v001"
    }
  }
}

{
  "code": 400,
  "message": "Invalid parameters: parameter 'prompt' is required"
}

{
  "code": 401,
  "message": "Authentication failed: invalid API key"
}

{
  "code": 429,
  "message": "Rate limit exceeded: 100 requests per minute, retry after 60 seconds"
}

{
  "code": 500,
  "message": "Internal server error"
}

Veo 3.1 I2V

[Core Function] Veo 3.1 I2V is Google’s cinematic image-to-video generation model. [Strengths] It generates high-fidelity 4K video from a starting image. It supports advanced features like first-and-last frame conditioning and referencing up to three images. [Best For] Highly recommended for: animating concept art, creating cinematic transitions between images, and high-end video production. [Limitations] When using first+last frame or reference-only modes, the duration parameter must strictly be 8. Negative prompts are not supported in reference-only mode. [Routing] Use this model by default for high-quality image-to-video tasks or when multiple reference images are provided.

POST

google

veo-3.1-i2v

curl --request POST \
  --url https://api.modellix.ai/api/v1/google/veo-3.1-i2v \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "prompt": "The character waves and smiles at the camera",
  "image": "https://example.com/frame.jpg"
}
'

{
  "code": 0,
  "message": "success",
  "data": {
    "status": "pending",
    "task_id": "task-i2v001",
    "model_id": "google/veo-3.1-i2v",
    "get_result": {
      "method": "GET",
      "url": "https://api.modellix.ai/api/v1/tasks/task-i2v001"
    }
  }
}

{
  "code": 400,
  "message": "Invalid parameters: parameter 'prompt' is required"
}

{
  "code": 401,
  "message": "Authentication failed: invalid API key"
}

{
  "code": 429,
  "message": "Rate limit exceeded: 100 requests per minute, retry after 60 seconds"
}

{
  "code": 500,
  "message": "Internal server error"
}

Authorizations

Authorization

string

header

required

API Key authentication. Format: Bearer YOUR_API_KEY.

Body

application/json

Option 1 — Image mode
Option 2 — Reference mode

Veo 3.1 / Veo 3.1 Fast image-to-video request. Choose one option — image mode and referenceImages mode are mutually exclusive. Resolution up to 4K. Constraints verified 2026-04-29 against Google raw API, see each parameter for details.

prompt

string

required

Video description text guiding the animation

Minimum string length: 1

Example:

"The character waves and smiles at the camera"

image

string

required

Starting frame. Accepts an image URL (e.g. https://example.com/frame.jpg).

Example:

"https://example.com/frame.jpg"

lastFrame

string

End frame. Accepts an image URL. Constraint: duration must be 8 when using this parameter.

Example:

"https://example.com/last-frame.jpg"

negativePrompt

string

Text describing what to avoid in the generated video.

Example:

"blurry, low quality, distorted"

aspectRatio

enum<string>

default:16:9

Video aspect ratio

Available options:

16:9,

9:16

Example:

"16:9"

duration

enum<string>

Video duration in seconds (string type). Constraint: When using lastFrame, must be 8 — values 4 or 6 will be rejected by Google. Otherwise 4, 6, 8 are all valid.

Available options:

4,

6,

8

Example:

"8"

resolution

enum<string>

Video resolution. Constraint: 1080p and 4k are only available when duration is 8.

Available options:

720p,

1080p,

4k

Example:

"1080p"

personGeneration

enum<string>

Person generation policy

Available options:

allow_adult

Example:

"allow_adult"

Response

Task submitted successfully

code

integer

required

Response code, 0 indicates success

Example:

0

message

string

required

Response message

Example:

"success"

data

object

required

Detailed data about the submitted asynchronous task.

Show child attributes

Veo 3 1 fast t2v Veo 3 1 lite i2v