How to Bypass CAPTCHA in C#

[CAPTCHAFORUM]

https://2captcha.com/lang/csharp

CAPTCHA is a security measure used to distinguish between human users and automated bots. If you're developing an application that requires bypassing CAPTCHA, you can use the 2Captcha service. This guide will show you how to solve CAPTCHA in C#.

Prerequisites​

Before starting, ensure you have:

• A 2Captcha account (Sign up here)
• Your 2Captcha API key
• C# development environment (Visual Studio or any C# IDE)
• System.Net.Http for sending web requests

Step 1: Find the CAPTCHA Site Key​

Most CAPTCHAs (especially Google reCAPTCHA) use a site key embedded in the page. To find it, inspect the webpage’s HTML and locate:

<script src="https://www.google.com/recaptcha/api.js" data-sitekey="SITE_KEY_HERE"></script>

Extract the data-sitekey value.

Step 2: Send CAPTCHA to 2Captcha​

Use HttpClient in C# to send a request to 2Captcha for solving the CAPTCHA.

using System;
using System.Net.Http;
using System.Threading.Tasks;
using Newtonsoft.Json.Linq;

class Program
{
private static readonly string API_KEY = "your_2captcha_api_key";
private static readonly string SITE_KEY = "site_key_from_target_website";
private static readonly string PAGE_URL = "https://targetwebsite.com";

static async Task Main()
{
using (HttpClient client = new HttpClient())
{
var requestData = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string, string>("key", API_KEY),
new KeyValuePair<string, string>("method", "userrecaptcha"),
new KeyValuePair<string, string>("googlekey", SITE_KEY),
new KeyValuePair<string, string>("pageurl", PAGE_URL),
new KeyValuePair<string, string>("json", "1")
});

HttpResponseMessage response = await client.PostAsync("http://2captcha.com/in.php", requestData);
string responseString = await response.Content.ReadAsStringAsync();
JObject jsonResponse = JObject.Parse(responseString);

if ((int)jsonResponse["status"] != 1)
{
Console.WriteLine("Error submitting captcha request");
return;
}

string captchaId = jsonResponse["request"].ToString();
Console.WriteLine("Captcha submitted. Waiting for solution...");

await Task.Delay(15000); // Wait for 2Captcha to solve it

string solution = await GetCaptchaSolution(client, captchaId);
Console.WriteLine("Captcha solved: " + solution);
}
}

private static async Task<string> GetCaptchaSolution(HttpClient client, string captchaId)
{
while (true)
{
HttpResponseMessage response = await client.GetAsync($"http://2captcha.com/res.php?key={API_KEY}&action=get&id={captchaId}&json=1");
string responseString = await response.Content.ReadAsStringAsync();
JObject jsonResponse = JObject.Parse(responseString);

if ((int)jsonResponse["status"] == 1)
{
return jsonResponse["request"].ToString();
}

Console.WriteLine("Solution not ready, retrying...");
await Task.Delay(5000);
}
}
}

Step 3: Submit CAPTCHA Solution​

Once 2Captcha provides the solution, you need to send it to the target website’s form:

var formData = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string, string>("g-recaptcha-response", solution),
new KeyValuePair<string, string>("other_form_fields", "values_here")
});

HttpResponseMessage finalResponse = await client.PostAsync(PAGE_URL, formData);
Console.WriteLine("Final Response: " + await finalResponse.Content.ReadAsStringAsync());

Using 2Captcha, you can effectively bypass CAPTCHA in C#. Always ensure your automation adheres to legal and ethical guidelines when interacting with websites.