hCAPTCHA Image

Overview

hCaptcha Image is a captcha type that requires users to identify and select images according to requirements, click points, or drag images.

🖼️

hCaptcha Token is widely used on many websites such as Cloudflare, Discord, OpenSea and many other services to protect against bots.

1. Create Task

Request

POST https://api.achicaptcha.com/createTask

Parameters

Parameter Name	Data Type	Required?	Description
`clientKey`	string	yes	Api key
`task.type`	string	yes	HCaptchaImageTask
`task.subType`	string	yes	Value equals 0
`task.image`	string	yes	List of base64 images separated by `\|` `base64_question1\|base64_question2\|...\|base64_question9\|base64_sample1\|base64_sample2\|...\|base64_sampleN` Note: Sample images may or may not be present. Images must be encoded to base64
`task.other`	string	yes	Question\|Image count\|Captcha type Example: `"Please identify and click on all pictures featuring a bird\|9\|grid"` - Question: "Please identify and click on all pictures featuring a bird" - Image count: 9 (Only count images in `question` grid, not `sample` images) - Captcha type: `grid` (select cells in 9 cells that meet condition) or `bbox` (click one/multiple points or drag to mark an object that meets condition) or `drag` (drag one/multiple puzzle pieces to create complete image)

Request Example

POST /createTask HTTP/1.1
Host: api.achicaptcha.com
Content-Type: application/json
 
{
  "clientKey": "YOUR_API_KEY",
  "task": {
    "type": "HCaptchaImageTask",
    "subType": "0",
    "image": "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg==|iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg==|...(9 base64 images joined by |)",
    "other": "Please identify and click on all pictures featuring a bird|9|grid"
  }
}

Response

When successful, server returns errorId = 0 and taskId

{
  "errorId": 0,
  "taskId": "f2fc70d6-c76b-4fba-9480-205ac1fe9fb9"
}

Image Samples to Send to Captcha Solving Server

Tip: For best captcha recognition quality, crop your image as shown in the red and purple boxes in the sample images below.
Make sure the cropped image resolution remains at least 500–600 pixels wide/high to ensure best results.

2. Get Result

Request

POST https://api.achicaptcha.com/getTaskResult

Parameters

Parameter Name	Data Type	Required?	Description
`clientKey`	string	yes	Api key
`taskId`	string	yes	TaskId obtained from (1)

Request Example

POST /getTaskResult HTTP/1.1
Host: api.achicaptcha.com
Content-Type: application/json
 
{
  "clientKey": "YOUR_API_KEY",
  "taskId": "f2fc70d6-c76b-4fba-9480-205ac1fe9fb9"
}

Response

{
  "errorId": 0,
  "status": "ready",
  // solution: coordinates of points to click (x1,y1,x2,y2,...) 
  "solution": "20,30,40,50"
}

Status Explanation

errorId = 0 and status = ready: Successfully solved, read result in solution.gRecaptchaResponse
errorId = 0 and status = processing: Solving captcha, wait 2 seconds and try again
errorId > 0: System error, returns error code and description

Integration Examples

import requests
import time
import base64
 
def image_url_to_base64(url):
    """Convert image URL to base64"""
    response = requests.get(url)
    return base64.b64encode(response.content).decode('utf-8')
 
def solve_hcaptcha_image(image_base64_list, question, image_count, captcha_type, api_key='YOUR_API_KEY'):
    # Step 1: Create task
    create_task_url = 'https://api.achicaptcha.com/createTask'
    create_task_payload = {
        'clientKey': api_key,
        'task': {
            'type': 'HCaptchaImageTask',
            'subType': '0',
            'image': image_base64_list,
            'other': f'{question}|{image_count}|{captcha_type}'
        }
    }
    
    response = requests.post(create_task_url, json=create_task_payload)
    result = response.json()
    
    if result['errorId'] != 0:
        raise Exception(result['errorDescription'])
    
    task_id = result['taskId']
    
    # Step 2: Get result
    get_result_url = 'https://api.achicaptcha.com/getTaskResult'
    
    while True:
        time.sleep(2)  # Wait 2 seconds
        
        get_result_payload = {
            'clientKey': api_key,
            'taskId': task_id
        }
        
        response = requests.post(get_result_url, json=get_result_payload)
        result = response.json()
        
        if result['errorId'] != 0:
            raise Exception(result['errorDescription'])
        
        if result['status'] == 'ready':
            return result['solution']['gRecaptchaResponse']
        
        # If status == 'processing', continue loop
 
# Usage
# Convert image URLs to base64
image_urls = [
    'https://example.com/image1.jpg',
    'https://example.com/image2.jpg',
    # ... other images
    'https://example.com/image9.jpg'
]
 
base64_images = [image_url_to_base64(url) for url in image_urls]
image_base64_list = '|'.join(base64_images)
 
question = 'Please identify and click on all pictures featuring a bird'
image_count = 9
captcha_type = 'grid'  # or 'bbox'
 
token = solve_hcaptcha_image(image_base64_list, question, image_count, captcha_type, 'YOUR_API_KEY')
print('hCaptcha token:', token)

Common Error Codes

Error Code	Description	Notes
0	success	Success
1	processing	Processing
2	missing required fields	Missing required fields, check parameters again
3	task not supported	Task type not supported
4	task creation failed	Task creation failed
5	client key does not exist	API key does not exist, check API key again
6	insufficient account balance	Insufficient account balance, add more credits
7	task failed, please create a new task	Task failed, please create a new task
8	task ID does not exist	Task ID does not exist

Best Practices

For best results when using Achicaptcha API, follow these principles:

1. Validate Input Data

Check image list before sending request
Images must be encoded to base64 before sending
Ensure correct format: base64_image1|base64_image2|...|base64_image9 or with additional sample images
Verify question and captcha type (grid/bbox) are accurate
Image count must match actual number of images in grid

2. Handle Multiple Rounds

hCaptcha may require solving multiple consecutive rounds
Achicaptcha API automatically handles these rounds
Solving time may be longer than text captcha (15-30 seconds)

3. Polling Interval

Wait at least 2 seconds between result checks
Don't spam API with too many consecutive requests
Set timeout to avoid infinite loops (recommended 120 seconds)

4. Retry Logic

Implement retry for temporary errors like ERROR_NO_SLOT_AVAILABLE
Use exponential backoff when retrying
Limit maximum retry attempts

5. API Key Security

Don't hardcode API key in code
Use environment variables
Don't expose API key on client-side

Useful links:

Funcaptcha Token