Gemini-3.1-Flash Official Image Generation

Generate images using Google Gemini 3.1 Flash official direct-connect model with thinking mode and extreme aspect ratios

POST /v1/images/generations

cURL

curl --request POST \
  --url https://toapis.com/v1/images/generations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
    "model": "gemini-3.1-flash-image-preview-official",
    "prompt": "An ink wash painting of mountains and rivers, layered peaks with swirling mist",
    "size": "16:9",
    "n": 1,
    "metadata": {
      "temperature": 1.0,
      "topP": 0.95,
      "resolution": "1K",
      "personGeneration": "ALLOW_ALL",
      "thinkingConfig": {
        "thinkingLevel": "HIGH"
      }
    }
  }'

200

{
  "id": "task_img_abc123def456",
  "object": "generation.task",
  "model": "gemini-3.1-flash-image-preview-official",
  "status": "queued",
  "progress": 0,
  "created_at": 1703884800,
  "metadata": {}
}

• Direct connection to Google Vertex AI using the Gemini 3.1 Flash Image native API
• Select the gemini-3.1-flash-image-preview-official model via the model parameter
• Supports text-to-image and image-to-image generation
• Supports native generation parameters like temperature, topP, and maxOutputTokens
• Supports resolution (1K/2K/4K), personGeneration, and imageOutputOptions image configuration
• Supports thinkingConfig thinking mode for improved complex scene generation
• Supports safetySettings for content safety control
• Supports extreme aspect ratios (4:1, 8:1)
• Asynchronous task management with task ID for result querying

Important Change: For better performance and cost control, we no longer support passing base64 image data directly in image_urls. Please use the Upload Image endpoint to upload images first, then use the returned URL in this API.

Authorizations

Authorization · string · required

All endpoints require Bearer Token authentication

Get API Key: Visit the API Key Management page to obtain your API Key

Add to request headers:

Authorization: Bearer YOUR_API_KEY

Body

model · string · default: "gemini-3.1-flash-image-preview-official" · required

Image generation model name

Example: "gemini-3.1-flash-image-preview-official"

prompt · string · required

Text description for image generation

size · string

Image aspect ratio

Supported formats:

• 1:1 - Square
• 3:2 / 2:3
• 3:4 / 4:3
• 4:5 / 5:4
• 9:16 / 16:9
• 21:9
• 4:1 / 8:1 - Extreme widescreen ratios

n · integer · default: 1

Number of images to generate

Fixed at 1

image_urls · string[]

Reference image URL array for image-to-image generation or editing

⚠️ Only URL format is supported (base64 is no longer supported)

• Publicly accessible image URLs (http:// or https://)
• Use the Upload Image endpoint to upload local images and get URLs

Limits:

• Maximum 14 images
• Maximum file size per image: 10MB
• Supported formats: .jpeg, .jpg, .png, .webp

metadata · object

Vertex AI native extension parameters

Show Show metadata fields

temperature · number

Generation temperature, controls output randomness

Range: 0.0 - 2.0, default 1.0

topP · number

Top-P sampling parameter

Range: 0.0 - 1.0, default 0.95

maxOutputTokens · integer

Maximum output tokens

Default 32768

resolution · string

Output image resolution, automatically mapped to Vertex AI native imageSize

Options: 1K, 2K, 4K, default 1K

personGeneration · string

Person generation control

Options:

• ALLOW_ALL - Allow generating all people (including adults and children)
• ALLOW_ADULT - Allow generating adults only
• ALLOW_NONE - Disallow generating people

imageOutputOptions · object

Image output format configuration

Show imageOutputOptions fields

mimeType · string

Output image format

Options: image/png, image/jpeg, image/webp

compressionQuality · integer

Compression quality (JPEG only)

thinkingConfig · object

Thinking mode configuration. When enabled, the model reasons before generating images, improving results for complex scenes

Show thinkingConfig fields

thinkingBudget · integer

Thinking token budget, controls the depth of model reasoning

Range: 0 - 24576, default is determined by the model

thinkingLevel · string

Thinking level

Options: LOW, MEDIUM, HIGH, MINIMAL

safetySettings · array

Safety settings array for content safety filtering

Show safetySettings elements

category · string

Safety category

Options: HARM_CATEGORY_HATE_SPEECH, HARM_CATEGORY_DANGEROUS_CONTENT, HARM_CATEGORY_SEXUALLY_EXPLICIT, HARM_CATEGORY_HARASSMENT

threshold · string

Filtering threshold

Options: OFF, BLOCK_LOW_AND_ABOVE, BLOCK_MEDIUM_AND_ABOVE, BLOCK_ONLY_HIGH

Response

id · string

Unique task identifier for querying task status

object · string

Object type, always generation.task

model · string

Model name used

status · string

Task status

• queued - Queued for processing
• in_progress - Processing
• completed - Successfully completed
• failed - Failed

progress · integer

Task progress percentage (0-100)

created_at · integer

Task creation timestamp (Unix timestamp)

metadata · object

Task metadata

cURL

curl --request POST \
  --url https://toapis.com/v1/images/generations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
    "model": "gemini-3.1-flash-image-preview-official",
    "prompt": "An ink wash painting of mountains and rivers, layered peaks with swirling mist",
    "size": "16:9",
    "n": 1,
    "metadata": {
      "temperature": 1.0,
      "topP": 0.95,
      "resolution": "1K",
      "personGeneration": "ALLOW_ALL",
      "thinkingConfig": {
        "thinkingLevel": "HIGH"
      }
    }
  }'

200

{
  "id": "task_img_abc123def456",
  "object": "generation.task",
  "model": "gemini-3.1-flash-image-preview-official",
  "status": "queued",
  "progress": 0,
  "created_at": 1703884800,
  "metadata": {}
}