POST images/upscale

Upscale Images

January 2, 2026

Request Headers
Request Body
Responses
Model
Examples
Try It

Upscale a previously generated image to 2K or 4K resolution. This endpoint uses Google Flow’s native image upscaling capabilities.

Important:

Upscaling is only supported for images generated with nano-banana-pro model. Other models (imagen-4, nano-banana) will return a 429 error.
4k resolution requires a paid Google account with an active subscription. Free accounts can only use 2k resolution.

https://api.useapi.net/v1/google-flow/images/upscale

Request Headers

Authorization: Bearer {API token}
Content-Type: application/json
# Alternatively you can use multipart/form-data
# Content-Type: multipart/form-data

API token is required, see Setup useapi.net for details.

Request Body

{
  "mediaGenerationId": "user:12345-email:6a6f...-image:CAMaJDMx...",
  "resolution": "2k"
}

mediaGenerationId is required. The mediaGenerationId from a previously generated image via POST /images.
resolution is optional. Target resolution for upscaling (default: 2k). Supported values: 2k, 4k.
captchaRetry is optional, number of captcha retry attempts (1-10, default: 3). Cycles through configured captcha providers starting with EzCaptcha if available.
captchaOrder is optional, explicit captcha provider sequence as comma-separated string (e.g., "EzCaptcha,EzCaptcha,CapSolver"). Maximum 10 entries. Each provider must have an API key configured.

Note: captchaRetry and captchaOrder are mutually exclusive - only one can be specified per request.

Responses

200 OK

Image upscaled successfully. Returns base64-encoded image data.

{
  "encodedImage": "/9j/4AAQSkZJRgABAQAAAQ...base64 encoded image data...",
  "captcha": {
    "service": "EzCaptcha",
    "taskId": "abc123...",
    "durationMs": 3500,
    "attempts": [
      {
        "service": "EzCaptcha",
        "taskId": "abc123...",
        "durationMs": 3500,
        "success": true
      }
    ]
  }
}

400 Bad Request

Invalid request (missing or invalid mediaGenerationId).
```
{
  "error": "mediaGenerationId is required"
}
```
401 Unauthorized

Invalid API token.
```
{
  "error": "Unauthorized"
}
```

403 Forbidden

Request rejected by Google.

Recommendations:

Ensure captchaRetry is set to at least 3 (default). Try increasing to a higher value (e.g., 5) to see if that helps
If issues persist, contact useapi.net support

{
  "error": {
    "code": 403,
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "PUBLIC_ERROR_SOMETHING_WENT_WRONG"
      }
    ],
    "message": "reCAPTCHA evaluation failed",
    "status": "PERMISSION_DENIED"
  },
  "captcha": {
    "service": "EzCaptcha",
    "taskId": "ab0251dc-6930-4a82-966a-71fe6ab6aa42",
    "durationMs": 5789,
    "attempts": [
      {
        "service": "EzCaptcha",
        "taskId": "ab0251dc-6930-4a82-966a-71fe6ab6aa42",
        "durationMs": 5789,
        "success": true
      }
    ]
  }
}

404 Not Found

Account not found or image not found.

{
  "error": "Google Flow account [email protected] not found"
}

429 Too Many Requests

Upscaling not supported for this image. Only images generated with nano-banana-pro model can be upscaled.

{
  "error": {
    "code": 429,
    "message": "Resource has been exhausted (e.g. check quota).",
    "status": "RESOURCE_EXHAUSTED",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "PUBLIC_ERROR_PER_MODEL_DAILY_QUOTA_REACHED_UPGRADEABLE",
        "metadata": {
          "canUpgradeForQuota": "true"
        }
      }
    ]
  },
  "captcha": {
    "service": "EzCaptcha",
    "taskId": "e07eb626-a824-40e1-ae03-51a631fbe6ef",
    "durationMs": 3519,
    "attempts": [
      {
        "service": "EzCaptcha",
        "taskId": "e07eb626-a824-40e1-ae03-51a631fbe6ef",
        "durationMs": 3519,
        "success": true
      }
    ]
  }
}

Model

encodedImage - Base64-encoded upscaled image data (JPEG format)
captcha - Captcha metadata for debugging/research
captcha.service - Provider that returned the successful token
captcha.taskId - Task ID from the captcha service
captcha.durationMs - Total time for all captcha attempts
captcha.attempts - Array of all captcha attempts (including failures)

{
  encodedImage: string                // Base64-encoded image (decode and save as .jpg)
  captcha?: {                         // Captcha metadata
    service: string                   // "EzCaptcha" | "CapSolver" | "YesCaptcha"
    taskId: string
    durationMs: number
    attempts: Array<{
      service: string
      taskId?: string
      durationMs: number
      success: boolean
      error?: string
    }>
  }
  error?: string | {                  // Error: string (useapi.net) or object (Google API)
    code: number
    message: string
    status: string
    details: Array<{
      '@type': string
      reason: string
    }>
  }
}

Examples

# First generate an image
curl -X POST \
     -H "Authorization: Bearer YOUR_API_TOKEN" \
     -H "Content-Type: application/json" \
     -d '{"prompt": "A beautiful sunset over mountains"}' \
     "https://api.useapi.net/v1/google-flow/images" > generate.json

# Extract mediaGenerationId from the response
MEDIA_ID=$(jq -r '.media[0].image.generatedImage.mediaGenerationId' generate.json)

# Upscale the image to 2K
curl -X POST \
     -H "Authorization: Bearer YOUR_API_TOKEN" \
     -H "Content-Type: application/json" \
     -d "{\"mediaGenerationId\": \"$MEDIA_ID\", \"resolution\": \"2k\"}" \
     "https://api.useapi.net/v1/google-flow/images/upscale" > upscale.json

# Decode base64 and save as image
jq -r '.encodedImage' upscale.json | base64 -d > upscaled_image.jpg

const token = 'YOUR_API_TOKEN';

// First generate an image
const generateResponse = await fetch('https://api.useapi.net/v1/google-flow/images', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${token}`,
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    prompt: 'A beautiful sunset over mountains'
  })
});

const generated = await generateResponse.json();
const mediaGenerationId = generated.media[0].image.generatedImage.mediaGenerationId;

// Upscale the image
const upscaleResponse = await fetch('https://api.useapi.net/v1/google-flow/images/upscale', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${token}`,
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    mediaGenerationId,
    resolution: '2k'
  })
});

const upscaled = await upscaleResponse.json();

// Decode base64 and save
const buffer = Buffer.from(upscaled.encodedImage, 'base64');
require('fs').writeFileSync('upscaled_image.jpg', buffer);
console.log('Upscaled image saved!');

import requests
import base64

token = 'YOUR_API_TOKEN'
headers = {
    'Authorization': f'Bearer {token}',
    'Content-Type': 'application/json'
}

# First generate an image
generate_response = requests.post(
    'https://api.useapi.net/v1/google-flow/images',
    headers=headers,
    json={'prompt': 'A beautiful sunset over mountains'}
)
generated = generate_response.json()
media_generation_id = generated['media'][0]['image']['generatedImage']['mediaGenerationId']

# Upscale the image
upscale_response = requests.post(
    'https://api.useapi.net/v1/google-flow/images/upscale',
    headers=headers,
    json={
        'mediaGenerationId': media_generation_id,
        'resolution': '2k'
    }
)
upscaled = upscale_response.json()

# Decode base64 and save
image_data = base64.b64decode(upscaled['encodedImage'])
with open('upscaled_image.jpg', 'wb') as f:
    f.write(image_data)
print('Upscaled image saved!')