Gemini image editing API

curl --request POST \
  --url https://bettertoken.ai/v1beta/models/{model}:generateContent \
  --header 'Content-Type: application/json' \
  --header 'x-goog-api-key: <api-key>' \
  --data '
{
  "contents": [
    {
      "role": "user",
      "parts": [
        {
          "text": "Change the mug to red. Keep its shape, the background, and the lighting unchanged."
        },
        {
          "inlineData": {
            "mimeType": "image/png",
            "data": "REPLACE_WITH_IMAGE_BASE64"
          }
        }
      ]
    }
  ],
  "generationConfig": {
    "responseModalities": [
      "IMAGE"
    ],
    "candidateCount": 1,
    "imageConfig": {
      "imageSize": "1K",
      "aspectRatio": "1:1"
    }
  }
}
'

import requests

url = "https://bettertoken.ai/v1beta/models/{model}:generateContent"

payload = {
    "contents": [
        {
            "role": "user",
            "parts": [{ "text": "Change the mug to red. Keep its shape, the background, and the lighting unchanged." }, { "inlineData": {
                        "mimeType": "image/png",
                        "data": "REPLACE_WITH_IMAGE_BASE64"
                    } }]
        }
    ],
    "generationConfig": {
        "responseModalities": ["IMAGE"],
        "candidateCount": 1,
        "imageConfig": {
            "imageSize": "1K",
            "aspectRatio": "1:1"
        }
    }
}
headers = {
    "x-goog-api-key": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {'x-goog-api-key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    contents: [
      {
        role: 'user',
        parts: [
          {
            text: 'Change the mug to red. Keep its shape, the background, and the lighting unchanged.'
          },
          {inlineData: {mimeType: 'image/png', data: 'REPLACE_WITH_IMAGE_BASE64'}}
        ]
      }
    ],
    generationConfig: {
      responseModalities: ['IMAGE'],
      candidateCount: 1,
      imageConfig: {imageSize: '1K', aspectRatio: '1:1'}
    }
  })
};

fetch('https://bettertoken.ai/v1beta/models/{model}:generateContent', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://bettertoken.ai/v1beta/models/{model}:generateContent",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'contents' => [
        [
                'role' => 'user',
                'parts' => [
                                [
                                                                'text' => 'Change the mug to red. Keep its shape, the background, and the lighting unchanged.'
                                ],
                                [
                                                                'inlineData' => [
                                                                                                                                'mimeType' => 'image/png',
                                                                                                                                'data' => 'REPLACE_WITH_IMAGE_BASE64'
                                                                ]
                                ]
                ]
        ]
    ],
    'generationConfig' => [
        'responseModalities' => [
                'IMAGE'
        ],
        'candidateCount' => 1,
        'imageConfig' => [
                'imageSize' => '1K',
                'aspectRatio' => '1:1'
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "x-goog-api-key: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://bettertoken.ai/v1beta/models/{model}:generateContent"

	payload := strings.NewReader("{\n  \"contents\": [\n    {\n      \"role\": \"user\",\n      \"parts\": [\n        {\n          \"text\": \"Change the mug to red. Keep its shape, the background, and the lighting unchanged.\"\n        },\n        {\n          \"inlineData\": {\n            \"mimeType\": \"image/png\",\n            \"data\": \"REPLACE_WITH_IMAGE_BASE64\"\n          }\n        }\n      ]\n    }\n  ],\n  \"generationConfig\": {\n    \"responseModalities\": [\n      \"IMAGE\"\n    ],\n    \"candidateCount\": 1,\n    \"imageConfig\": {\n      \"imageSize\": \"1K\",\n      \"aspectRatio\": \"1:1\"\n    }\n  }\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("x-goog-api-key", "<api-key>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://bettertoken.ai/v1beta/models/{model}:generateContent")
  .header("x-goog-api-key", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"contents\": [\n    {\n      \"role\": \"user\",\n      \"parts\": [\n        {\n          \"text\": \"Change the mug to red. Keep its shape, the background, and the lighting unchanged.\"\n        },\n        {\n          \"inlineData\": {\n            \"mimeType\": \"image/png\",\n            \"data\": \"REPLACE_WITH_IMAGE_BASE64\"\n          }\n        }\n      ]\n    }\n  ],\n  \"generationConfig\": {\n    \"responseModalities\": [\n      \"IMAGE\"\n    ],\n    \"candidateCount\": 1,\n    \"imageConfig\": {\n      \"imageSize\": \"1K\",\n      \"aspectRatio\": \"1:1\"\n    }\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://bettertoken.ai/v1beta/models/{model}:generateContent")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["x-goog-api-key"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"contents\": [\n    {\n      \"role\": \"user\",\n      \"parts\": [\n        {\n          \"text\": \"Change the mug to red. Keep its shape, the background, and the lighting unchanged.\"\n        },\n        {\n          \"inlineData\": {\n            \"mimeType\": \"image/png\",\n            \"data\": \"REPLACE_WITH_IMAGE_BASE64\"\n          }\n        }\n      ]\n    }\n  ],\n  \"generationConfig\": {\n    \"responseModalities\": [\n      \"IMAGE\"\n    ],\n    \"candidateCount\": 1,\n    \"imageConfig\": {\n      \"imageSize\": \"1K\",\n      \"aspectRatio\": \"1:1\"\n    }\n  }\n}"

response = http.request(request)
puts response.read_body

{
  "candidates": [
    {
      "content": {
        "role": "model",
        "parts": [
          {
            "inlineData": {
              "mimeType": "image/png",
              "data": "BASE64_IMAGE_DATA"
            }
          }
        ]
      },
      "finishReason": "STOP"
    }
  ]
}

POST

v1beta

models

{model}

:generateContent

Gemini image editing API

curl --request POST \
  --url https://bettertoken.ai/v1beta/models/{model}:generateContent \
  --header 'Content-Type: application/json' \
  --header 'x-goog-api-key: <api-key>' \
  --data '
{
  "contents": [
    {
      "role": "user",
      "parts": [
        {
          "text": "Change the mug to red. Keep its shape, the background, and the lighting unchanged."
        },
        {
          "inlineData": {
            "mimeType": "image/png",
            "data": "REPLACE_WITH_IMAGE_BASE64"
          }
        }
      ]
    }
  ],
  "generationConfig": {
    "responseModalities": [
      "IMAGE"
    ],
    "candidateCount": 1,
    "imageConfig": {
      "imageSize": "1K",
      "aspectRatio": "1:1"
    }
  }
}
'

import requests

url = "https://bettertoken.ai/v1beta/models/{model}:generateContent"

payload = {
    "contents": [
        {
            "role": "user",
            "parts": [{ "text": "Change the mug to red. Keep its shape, the background, and the lighting unchanged." }, { "inlineData": {
                        "mimeType": "image/png",
                        "data": "REPLACE_WITH_IMAGE_BASE64"
                    } }]
        }
    ],
    "generationConfig": {
        "responseModalities": ["IMAGE"],
        "candidateCount": 1,
        "imageConfig": {
            "imageSize": "1K",
            "aspectRatio": "1:1"
        }
    }
}
headers = {
    "x-goog-api-key": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {'x-goog-api-key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    contents: [
      {
        role: 'user',
        parts: [
          {
            text: 'Change the mug to red. Keep its shape, the background, and the lighting unchanged.'
          },
          {inlineData: {mimeType: 'image/png', data: 'REPLACE_WITH_IMAGE_BASE64'}}
        ]
      }
    ],
    generationConfig: {
      responseModalities: ['IMAGE'],
      candidateCount: 1,
      imageConfig: {imageSize: '1K', aspectRatio: '1:1'}
    }
  })
};

fetch('https://bettertoken.ai/v1beta/models/{model}:generateContent', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://bettertoken.ai/v1beta/models/{model}:generateContent",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'contents' => [
        [
                'role' => 'user',
                'parts' => [
                                [
                                                                'text' => 'Change the mug to red. Keep its shape, the background, and the lighting unchanged.'
                                ],
                                [
                                                                'inlineData' => [
                                                                                                                                'mimeType' => 'image/png',
                                                                                                                                'data' => 'REPLACE_WITH_IMAGE_BASE64'
                                                                ]
                                ]
                ]
        ]
    ],
    'generationConfig' => [
        'responseModalities' => [
                'IMAGE'
        ],
        'candidateCount' => 1,
        'imageConfig' => [
                'imageSize' => '1K',
                'aspectRatio' => '1:1'
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "x-goog-api-key: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://bettertoken.ai/v1beta/models/{model}:generateContent"

	payload := strings.NewReader("{\n  \"contents\": [\n    {\n      \"role\": \"user\",\n      \"parts\": [\n        {\n          \"text\": \"Change the mug to red. Keep its shape, the background, and the lighting unchanged.\"\n        },\n        {\n          \"inlineData\": {\n            \"mimeType\": \"image/png\",\n            \"data\": \"REPLACE_WITH_IMAGE_BASE64\"\n          }\n        }\n      ]\n    }\n  ],\n  \"generationConfig\": {\n    \"responseModalities\": [\n      \"IMAGE\"\n    ],\n    \"candidateCount\": 1,\n    \"imageConfig\": {\n      \"imageSize\": \"1K\",\n      \"aspectRatio\": \"1:1\"\n    }\n  }\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("x-goog-api-key", "<api-key>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://bettertoken.ai/v1beta/models/{model}:generateContent")
  .header("x-goog-api-key", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"contents\": [\n    {\n      \"role\": \"user\",\n      \"parts\": [\n        {\n          \"text\": \"Change the mug to red. Keep its shape, the background, and the lighting unchanged.\"\n        },\n        {\n          \"inlineData\": {\n            \"mimeType\": \"image/png\",\n            \"data\": \"REPLACE_WITH_IMAGE_BASE64\"\n          }\n        }\n      ]\n    }\n  ],\n  \"generationConfig\": {\n    \"responseModalities\": [\n      \"IMAGE\"\n    ],\n    \"candidateCount\": 1,\n    \"imageConfig\": {\n      \"imageSize\": \"1K\",\n      \"aspectRatio\": \"1:1\"\n    }\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://bettertoken.ai/v1beta/models/{model}:generateContent")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["x-goog-api-key"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"contents\": [\n    {\n      \"role\": \"user\",\n      \"parts\": [\n        {\n          \"text\": \"Change the mug to red. Keep its shape, the background, and the lighting unchanged.\"\n        },\n        {\n          \"inlineData\": {\n            \"mimeType\": \"image/png\",\n            \"data\": \"REPLACE_WITH_IMAGE_BASE64\"\n          }\n        }\n      ]\n    }\n  ],\n  \"generationConfig\": {\n    \"responseModalities\": [\n      \"IMAGE\"\n    ],\n    \"candidateCount\": 1,\n    \"imageConfig\": {\n      \"imageSize\": \"1K\",\n      \"aspectRatio\": \"1:1\"\n    }\n  }\n}"

response = http.request(request)
puts response.read_body

{
  "candidates": [
    {
      "content": {
        "role": "model",
        "parts": [
          {
            "inlineData": {
              "mimeType": "image/png",
              "data": "BASE64_IMAGE_DATA"
            }
          }
        ]
      },
      "finishReason": "STOP"
    }
  ]
}

Send a reference image and an editing instruction to Nano Banana Pro, 2, or 2.1. POST /v1beta/models/{model}:generateContent Text-to-image and image editing use the same endpoint. Image editing adds a reference image to the request.

Reference images

Use a separate part for each text instruction and image. inlineData.data contains raw base64 without a Data URL prefix. Use PNG or JPEG reference images; this endpoint accepts JSON, not multipart uploads or image URLs. Before sending, replace REPLACE_WITH_IMAGE_BASE64 with your image’s base64 and set inlineData.mimeType to match the file. The sample instruction describes a mug; change it too if you use a different subject.

Try a request

Prepare your reference image first. Enter your BetterToken API Key in x-goog-api-key and select model. In contents, provide the editing instruction and image data. Check that inlineData.data has been replaced and inlineData.mimeType matches the file, then click Send.

Clicking Send makes a real generation request and may incur charges. Wait for the synchronous response. After a timeout or disconnection, check usage records and the request result before sending it again.

All three offer 1K, 2K, and 4K. Nano Banana 2 and 2.1 support 14 aspect ratios; Pro supports 10. X-BetterToken-Max-Images is a delivery and billing cap, not a guaranteed image count. Aspect ratios

BetterToken API does not support search-assisted image generation, including Google Web Search and Image Search grounding. Do not add search tools.

Use non-streaming generateContent. Files / fileData, Batch, Interactions, and streaming are not supported by this integration.

Read the response

Images are returned in candidates[].content.parts[].inlineData. Iterate over the parts, skip thought: true, decode data, and choose the file extension from mimeType. Do not assume the image is always the first part or always PNG.

Authorizations

x-goog-api-key

string

header

required

BetterToken API Key.

Headers

X-BetterToken-Max-Images

integer

default:1

Maximum number of returned and billable images, not a guaranteed count. Defaults to 1.

Required range: 1 <= x <= 4

Path Parameters

model

enum<string>

default:nano-banana-2.1

required

BetterToken Model ID. Choose one of the three Nano Banana models.

Available options:

nano-banana-pro,

nano-banana-2,

nano-banana-2.1

Body

application/json

contents

object[]

required

Conversation contents. Keep the complete model content and thoughtSignature for follow-up edits.

Minimum array length: 1

Show child attributes

generationConfig

object

Image generation settings.

Show child attributes

Response

Generation response. Inspect final image parts and finishReason.

candidates

object[]

Show child attributes

promptFeedback

object

usageMetadata

object

​Reference images

​Try a request

​Read the response

​Related guides

Authorizations

Headers

Path Parameters

Body

Response

Reference images

Try a request

Read the response

Related guides