How To Solve CAPTCHA In Python Using 2Captcha
Published: 2023-04-13 11:17:37

You may have solved millions of captchas for verification, which can be a tedious chore when you need to authenticate your identity as a human. These websites offer an additional layer of security by utilizing captcha services to prevent bots and automation scripts from accessing their website.

## What is CAPTCHA?

CAPTCHA (**Completely Automated Public Turing Test to Tell Computers and Humans Apart**) is a form of challenge-response test used to assess whether or not a user is human.

CAPTCHAs display jumbled, scrambled, or distorted text, images, numbers, and audio that is tough for computers to solve but relatively easy for people to solve. These are used to protect websites and applications against harmful actions.

## 2captcha API

There are numerous applications and services available to assist us in solving a captcha in seconds. **2captcha** is a website that offers captcha-solving services.

[2captcha](https://2captcha.com/) provides API for various programming languages, including Python, and we'll utilise the `2captcha-python` library to solve the captcha in a few steps.

## Installing dependencies

The primary work is to install the Python library called 2captcha-python. Run the following command in your terminal.

```bash
pip install 2captcha-python
```

Please keep in mind that we are using pip to install the library. If you are not using pip, the installation command will be different.

## Solving reCAPTCHA

We'll use a reCAPTCHA testing website and here's the URL of the website [https://patrickhlauke.github.io/recaptcha/](https://patrickhlauke.github.io/recaptcha/). It provides a reCAPTCHA widget for testing purposes.


![reCAPTCHA demo site](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ty1cwtcyn2tzc4m3pi65.png)

### Code

First, we must import the library and create an instance of the class `TwoCaptcha`, which we will initialise with the API key. To make a **POST** request to the target site, we also need the `requests` library.

```python
# Imported the required libs
from twocaptcha import TwoCaptcha
import requests

# Instance of TwoCaptcha
solver = TwoCaptcha('YOUR_API_KEY')
```

After we've built the instance, the next step is to obtain the token from the 2captcha server.

```python
# Target website URL
site_url = "https://patrickhlauke.github.io/recaptcha/"

# Getting the token
try:
    # For solving reCAPTCHA
    token = captcha_solver.recaptcha(
        sitekey='6Ld2sf4SAAAAAKSgzs0Q13IZhY02Pyo31S2jgOB5',
        url=site_url
    )

# Handling the exceptions
except Exception as e:
    raise SystemExit('Error: CAPTCHA token not recieved.')

# Print the token and exit the program
else:
    SystemExit('Token- ' + str(token))
```

We called the `recaptcha` method from the instance `captcha_solver` within the `try` block and passed the reCAPTCHA data-sitekey to the `sitekey` parameter and the URL of the target site to the `url` parameter.

To get the **sitekey** from the website, open it in inspect mode and look for the tag `<iframe>` with `title="reCAPTCHA"` and you'll find the key within the `src` attribute.


![reCAPTCHA sitekey](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/4ti24dh997ri99azfhty.png)

If any exceptions are triggered within the `except` block, the program will display an error message and exit. If the program is successfully executed, it will return the token that will be used to solve reCAPTCHA and then quit.

The final step will be to transfer the token to the target site, which will be accomplished by sending a **POST** request to the target site via the `requests` library.

```python
# Imported the required libs
from twocaptcha import TwoCaptcha
import requests

# Instance of TwoCaptcha
captcha_solver = TwoCaptcha('YOUR_API_KEY')

# Target website URL
site_url = "https://patrickhlauke.github.io/recaptcha/"

# Getting the token
try:
    # For solving reCAPTCHA
    token = captcha_solver.recaptcha(
        sitekey='6Ld2sf4SAAAAAKSgzs0Q13IZhY02Pyo31S2jgOB5',
        url=site_url
    )

# Handling the exceptions
except Exception as e:
    raise SystemExit('Error: CAPTCHA token not recieved.')

# Sending the token to the website
else:
    # Sending spoof user-agent
    headers = {'user-agent': 'Mozilla/5.0 Chrome/52.0.2743.116 Safari/537.36'}

    # Sending recieved token
    data = {'recaptcha-token': str(token)}

    # Making POST request to the target site
    token_response = requests.post(site_url, headers=headers, data=data)

    print('Token sent')
```

We changed the `else` part of the code, and the result is the code seen above. Before performing the **POST** request to the target site, we've established certain configurations to send along with the request within the `else` block.

We used the `requests` library's `post` function to send a **POST** request to the target site, passing the `site_url` (target site URL), `headers` (containing the user-agent), and `data` (containing token). The data can contain more parameters depending on the form.

Note: The received token from the 2captcha servers will only be valid for 120 seconds, so you need to submit the token to the target site within the time limit.

## Solving hCAPTCHA

The URL of the hCAPTCHA demo site is [https://accounts.hcaptcha.com/demo](https://accounts.hcaptcha.com/demo).


![hCAPTCHA demo site](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/qik07al3wum8gcguguag.png)

The procedure will be the same as with reCAPTCHA, with the exception that we must modify the method to hcaptcha from the `2captcha-python` package.

```python
# Imported the required libs
from twocaptcha import TwoCaptcha
import requests

# Instance of TwoCaptcha
captcha_solver = TwoCaptcha('YOUR_API_KEY')

# Target website URL
site_url = "https://accounts.hcaptcha.com/demo"

# Getting the token
try:
    # For solving hCAPTCHA
    token = captcha_solver.hcaptcha(
        sitekey='a5f74b19-9e45-40e0-b45d-47ff91b7a6c2',
        url=site_url
    )

# Handling the exceptions
except Exception as e:
    raise SystemExit('Error: CAPTCHA token not recieved.')

# Sending the token to the website
else:
    # Sending spoof user-agent
    headers = {'user-agent': 'Mozilla/5.0 Chrome/52.0.2743.116 Safari/537.36'}

    # Sending recieved token
    data = {'hcaptcha-token': str(token)}

    # Making POST request to the target site
    token_response = requests.post(site_url, headers=headers, data=data)

    print('Token sent')
```

We'll get the `sitekey` of the hCAPTCHA within the `src` attribute of the `<iframe>` tag.


![hCAPTCHA sitekey](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/rv5k8rsvlvr0g0gqm9fz.png)

## Conclusion

We've used the `2captcha-python` package for solving the reCAPTCHA and hCAPTCHA. The `2captcha-python` package provided by 2captcha provides captcha-solving services and almost all types of captcha can be solved using their APIs. They provide a browser extension for solving CAPTCHAs.