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POST
/
v1
/
chat
/
completions
Image to Image
curl --request POST \
  --url https://gptproto.com/v1/chat/completions \
  --header 'Authorization: <authorization>' \
  --header 'Content-Type: application/json' \
  --data '{
  "messages": [
    {
      "role": "<string>",
      "content": "<string>",
      "experimental_attachments": [
        {
          "contentType": "<string>",
          "url": "<string>"
        }
      ]
    }
  ],
  "model": "<string>"
}'
{
  "error": {
    "message": "Invalid signature",
    "type": "401"
  }
}

​
Overview

Google Gemini 2.5 Flash Image preview, a powerful new image generation and editing model with advanced features and creative control.

​
Supported inputs & outputs :

Inputs: Text and Images Outputs: Text and image

​
Authentication

This endpoint requires authentication using a Bearer token.
​
Authorization
string
default:"sk-***********"
required
Your API key in the format: YOUR_API_KEY

​
Request Body

​
messages
array
required
Array of message objects for the conversation
​
model
string
default:"gemini-2.5-flash-image-preview"
required

​
Image to Image

The default output size for chat mode is 1:1 (1024x1024) 
curl -X POST "https://gptproto.com/v1/chat/completions" \
  -H "Authorization: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "messages": [
    {
      "role": "user",
      "content": "Two people standing together",
      "experimental_attachments": [
        {
          "contentType": "image/png",
          "url": "https://mgszhhytxjyitifbalro.supabase.co/storage/v1/object/public/chat-attachments/uploads/guakmauqtr.png"
        },
        {
          "contentType": "image/jpeg",
          "url": "https://mgszhhytxjyitifbalro.supabase.co/storage/v1/object/public/chat-attachments/uploads/3ox9ikxbcxc.jpeg"
        }
      ],
  	  "model": "gemini-2.5-flash-image-preview"
    }
  ]
}'

​
Response

{
  "candidates": [
      {
          "content": {
              "role": "model",
              "parts": [
                  {
                      "inlineData": {
                          "mimeType": "image/png",
                          "data": "base64"
                      }
                  }
              ]
          },
          "finishReason": "STOP"
      }
  ],
  "usageMetadata": {
      "promptTokenCount": 1302,
      "candidatesTokenCount": 1290,
      "totalTokenCount": 2592,
      "thoughtsTokenCount": 0,
      "promptTokensDetails": [
          {
              "modality": "IMAGE",
              "tokenCount": 1290
          },
          {
              "modality": "TEXT",
              "tokenCount": 12
          }
      ]
  },
  "modelVersion": "gemini-2.5-flash-image-preview"
}

{
  "error": {
    "message": "Invalid signature",
    "type": "401"
  }
}