How to Bypass Text Captcha (Letter Captcha)

Bypassing text CAPTCHAs can be a challenging task for automated systems, but the 2Captcha API provides a simple solution. This guide offers a step-by-step tutorial on integrating the captcha solver API to effectively solve text-based CAPTCHAs. Follow these instructions to streamline the process and achieve optimal results.

Text captcha and letter captcha both refer to the type of captcha that displays distorted characters or letters that the user must identify and type in to prove they are human. So, essentially, they are the same type of captcha, just described in slightly different ways.

Step 1: Prerequisites

Before starting, ensure you have:

2Captcha API Key: Sign up on captcha solver and obtain your API key from the dashboard.
HTTP Client: Use a tool like cURL, Postman, or a library to perform HTTP requests.
Programming Environment: Python is used in this guide, but the API is compatible with other languages.

Step 2: Understand the API Workflow

Key Endpoints:

Create Task: Send the CAPTCHA for solving.
- Endpoint: https://api.2captcha.com/createTask
Get Task Result: Retrieve the solved CAPTCHA response.
- Endpoint: https://api.2captcha.com/getTaskResult

Step 3: Create a CAPTCHA Task

The first step is to create a task with the CAPTCHA details. Here is how to send the request:

Example Request (Python):

import requests

API_KEY = "your_2captcha_api_key"

url = "https://api.2captcha.com/createTask"

data = {
    "clientKey": API_KEY,
    "task": {
        "type": "TextCaptchaTask",
        "comment": "What is the capital of France?"
    }
}

response = requests.post(url, json=data)
response_data = response.json()

if response_data["errorId"] == 0:
    task_id = response_data["taskId"]
    print(f"Task created successfully. Task ID: {task_id}")
else:
    print(f"Error: {response_data['errorDescription']}")

Parameters:

clientKey: Your unique API key.
type: Must be TextCaptchaTask.
comment: The text-based CAPTCHA question.

Step 4: Check Task Result

After creating the task, use the Task ID to retrieve the result. Allow a few seconds for the task to process.

Example Request (Python):

import time

result_url = "https://api.2captcha.com/getTaskResult"

while True:
    result_response = requests.post(result_url, json={
        "clientKey": API_KEY,
        "taskId": task_id
    })
    result_data = result_response.json()

    if result_data["status"] == "ready":
        answer = result_data["solution"]["text"]
        print(f"CAPTCHA Solved: {answer}")
        break
    else:
        print("Waiting for the result...")
        time.sleep(5)

Parameters:

clientKey: Your API key.
taskId: ID of the created task.

Step 5: How to Bypass Text-Based CAPTCHA

Letter-based CAPTCHAs require recognizing distorted or obfuscated text. The 2Captcha API provides an OCR-based approach to solve these CAPTCHAs.

Create a Text CAPTCHA Task

To bypass a letter-based CAPTCHA, submit an image of the CAPTCHA for processing.

Example Request (Python):

import base64

image_path = "captcha_image.png"
with open(image_path, "rb") as image_file:
    encoded_image = base64.b64encode(image_file.read()).decode("utf-8")

url = "https://api.2captcha.com/createTask"

data = {
    "clientKey": API_KEY,
    "task": {
        "type": "ImageToTextTask",
        "body": encoded_image,
        "phrase": False,
        "case": True
    }
}

response = requests.post(url, json=data)
response_data = response.json()

if response_data["errorId"] == 0:
    task_id = response_data["taskId"]
    print(f"Task created successfully. Task ID: {task_id}")
else:
    print(f"Error: {response_data['errorDescription']}")

Parameters:

clientKey: Your unique API key.
type: Must be ImageToTextTask.
body: Base64-encoded image of the CAPTCHA.
phrase: Set to True if the CAPTCHA requires multiple words.
case: Set to True if case sensitivity is required.

Retrieve the Solved CAPTCHA

Use the same method as Step 4 to get the solution.

Step 6: Handle API Errors

While working with the 2Captcha API, you may encounter errors. Here are some common scenarios and how to address them:

Common Error Codes

Error Code	Description
`1`	Invalid API key.
`10`	CAPTCHA not solvable.
`100`	Maximum task count reached.

Error Handling in Python

To ensure errors are handled gracefully, include error-checking logic in your script:

def handle_api_error(response_data):
    if response_data["errorId"] != 0:
        print(f"Error occurred: {response_data['errorDescription']}")
        # Additional error-handling logic
        if response_data["errorId"] == 1:
            raise ValueError("Invalid API Key")
        elif response_data["errorId"] == 10:
            print("CAPTCHA not solvable. Please try a different task.")
        else:
            print("Unknown error. Refer to the documentation for details.")

Use this function during both task creation and result retrieval to efficiently manage errors.

Step 7: Optimize Performance

To improve your system's performance and reliability, follow these best practices:

Use Webhooks for Notifications
Instead of polling the API repeatedly, configure a webhook to receive a callback once the CAPTCHA is solved. This reduces server load and response times. For setup details, refer to the webhook documentation.
Monitor Account Balance
Always check your account balance using the getBalance endpoint before creating tasks.
Retry with Exponential Backoff
Implement retry logic with exponential backoff to minimize request failures.
Log and Monitor
Maintain detailed logs of API interactions and monitor unusual patterns to ensure smooth operation.

Conclusion

Integrating the 2Captcha API to bypass both text and letter-based CAPTCHAs is a reliable and efficient approach for automating tasks requiring human-like interactions. By following this guide, you can set up and optimize your system to handle various CAPTCHA challenges seamlessly. For more details, refer to the captcha solver documentation.