Native Gemini Format

Endpoint

POST /v1beta/models/{modeName}:generateContent

Header Parameters

Name	Type	Required	Description	Example
Authorization	string	No		Bearer {your_token}

Path Parameters

Name	Type	Required	Description	Example
modeName	string	Yes	gemini-3-pro-image-preview-1k, gemini-3-pro-image-preview-2k, gemini-3-pro-image-preview-4k, gemini-3.1-flash-image-preview-512, gemini-3.1-flash-image-preview-1k, gemini-3.1-flash-image-preview-2k, gemini-3.1-flash-image-preview-4k	Model name:

Request Body Parameters

Field	Type	Required	Title	Description
generationConfig.imageConfig.aspectRatio	string	Yes	Ratio	Optional values:1:1, 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 21:9
generationConfig.imageConfig.outputFormat	string	Yes	format	Optional values: jpeg, png
contents	array	No	Example field	Appears in a request example; no separate field description is provided.
generationConfig	object	No	Example field	Appears in a request example; no separate field description is provided.

Request Examples

default

{
  "contents": [
    {
      "role": "user",
      "parts": [
        {
          "text": " "
        }
      ]
    }
  ],
  "generationConfig": {
    "responseModalities": [
      "IMAGE"
    ]
  }
}

curl -X POST "{BASE_URL}/v1beta/models/{modeName}:generateContent" \
 -H "Authorization: Bearer sk-***" \
 -H "Content-Type: application/json" \
 -d '{"contents": [{"role": "user",
 "parts": [{"text": " "}]}],
 "generationConfig": {"responseModalities": ["IMAGE"]}}'

{
  "contents": [
    {
      "role": "user",
      "parts": [
        {
          "text": "[] HA[style], []and[]. [style]and[style].. "
        }
      ]
    }
  ],
  "generationConfig": {
    "responseModalities": [
      "IMAGE"
    ],
    "imageConfig": {
      "aspectRatio": "9:16",
      "imageSize": "1K"
    }
  }
}

curl -X POST "{BASE_URL}/v1beta/models/{modeName}:generateContent" \
 -H "Authorization: Bearer sk-***" \
 -H "Content-Type: application/json" \
 -d '{"contents": [{"role": "user",
 "parts": [{"text": "[] HA[style], []and[]. [style]and[style].. "}]}],
 "generationConfig": {"responseModalities": ["IMAGE"],
 "imageConfig": {"aspectRatio": "9:16",
 "imageSize": "1K"}}}'

image editing

{
  "contents": [
    {
      "role": "user",
      "parts": [
        {
          "text": " [] [] one[styledescription]. reserved [], [new /]"
        },
        {
          "inline_data": {
            "mime_type": "image/jpeg",
            "data": "image_base64"
          }
        }
      ]
    }
  ],
  "generationConfig": {
    "responseModalities": [
      "IMAGE"
    ],
    "imageConfig": {
      "aspectRatio": "9:16",
      "imageSize": "1K"
    }
  }
}

curl -X POST "{BASE_URL}/v1beta/models/{modeName}:generateContent" \
 -H "Authorization: Bearer sk-***" \
 -H "Content-Type: application/json" \
 -d '{"contents": [{"role": "user",
 "parts": [{"text": " [] [] one[styledescription]. reserved [], [new /]"},
 {"inline_data": {"mime_type": "image/jpeg",
 "data": "image_base64"}}]}],
 "generationConfig": {"responseModalities": ["IMAGE"],
 "imageConfig": {"aspectRatio": "9:16",
 "imageSize": "1K"}}}'

{
  "contents": [
    {
      "role": "user",
      "parts": [
        {
          "text": "useprovides image, [image2items in] [image1items in]. [image1items in]. [description]. "
        },
        {
          "inline_data": {
            "mime_type": "image/jpeg",
            "data": "image_base64_1"
          }
        },
        {
          "inline_data": {
            "mime_type": "image/jpeg",
            "data": "image_base64_2"
          }
        }
      ]
    }
  ],
  "generationConfig": {
    "responseModalities": [
      "IMAGE"
    ],
    "imageConfig": {
      "aspectRatio": "9:16",
      "imageSize": "1K"
    }
  }
}

curl -X POST "{BASE_URL}/v1beta/models/{modeName}:generateContent" \
 -H "Authorization: Bearer sk-***" \
 -H "Content-Type: application/json" \
 -d '{"contents": [{"role": "user",
 "parts": [{"text": "useprovides image, [image2items in] [image1items in]. [image1items in]. [description]. "},
 {"inline_data": {"mime_type": "image/jpeg",
 "data": "image_base64_1"}},
 {"inline_data": {"mime_type": "image/jpeg",
 "data": "image_base64_2"}}]}],
 "generationConfig": {"responseModalities": ["IMAGE"],
 "imageConfig": {"aspectRatio": "9:16",
 "imageSize": "1K"}}}'

Response Fields

Field	Type	Required	Title	Description

Response Examples

Success

{
  "candidates": [
    {
      "content": {
        "role": "model",
        "parts": [
          {
            "inlineData": {
              "mimeType": "image/jpeg",
              "data": "image_base64"
            }
          }
        ]
      },
      "finishReason": "STOP",
      "safetyRatings": []
    }
  ],
  "usageMetadata": {
    "promptTokenCount": 0,
    "candidatesTokenCount": 0,
    "totalTokenCount": 0
  }
}