How to bypass captcha in C#

Introduction

Need to add captcha solving to your C# application? The 2captcha-csharp module is the official tool from 2Captcha that handles all the complex work of interacting with the API.

In this guide, we will explain why you should choose this library, how to connect it quickly, and what possibilities it opens for your projects.

General Information

2captcha-csharp is a native C# client for the 2Captcha API. It provides a convenient object-oriented interface for sending recognition tasks and getting results.

Why You Should Use This Module

• Single interface for all captcha types - no need to learn different endpoints, the library abstracts the details
• Full async support - use async/await without blocking the main thread
• Flexible configuration - set timeouts, polling intervals, callback notifications for your task
• Built-in error handling - clear exceptions instead of raw HTTP responses
• Proxy support - pass proxies right in the captcha object, no extra steps needed
• Up-to-date docs and support - the library is maintained by the 2Captcha team

Environment Setup

Minimum requirements:

• .NET SDK 5.0 or higher
• API key from your 2Captcha account dashboard

Install in one step via NuGet:

dotnet add package 2captcha-csharp

After installation, add the needed using statements to your file:

using TwoCaptcha;
using TwoCaptcha.Captcha;

How the Module Works

Main Class: TwoCaptcha

All interactions with the service go through an instance of the TwoCaptcha class:

var solver = new TwoCaptcha("YOUR_API_KEY");

Flexible Behavior Configuration

You can configure the client for your needs:

var solver = new TwoCaptcha(apiKey)
{
    DefaultTimeout = 120,        // timeout for regular captchas
    RecaptchaTimeout = 600,      // separate timeout for reCAPTCHA
    PollingInterval = 10,        // result polling interval
    SoftId = 123,                // your software ID for statistics
    Callback = "https://your.site/webhook",  // URL for async notifications
    ExtendedResponse = true      // get response in extended JSON
};

Configuration Properties

Basic Usage Pattern

Regardless of captcha type, the workflow looks the same:

using System;
using System.Threading.Tasks;
using TwoCaptcha;
using TwoCaptcha.Captcha;

class Program
{
    static async Task Main(string[] args)
    {
        var apiKey = Environment.GetEnvironmentVariable("APIKEY_2CAPTCHA");
        var solver = new TwoCaptcha(apiKey);

        // 1. Create object of needed captcha type
        var captcha = new YourCaptchaType();
        // 2. Set parameters
        captcha.SetParam("value");
        
        try
        {
            // 3. Send and wait for result
            await solver.Solve(captcha);
            
            // 4. Use the response
            Console.WriteLine("Result: " + captcha.Code);
        }
        catch (Exception e)
        {
            Console.WriteLine("Error: " + e.Message);
        }
    }
}

This template works for any captcha type, only the class and parameter set change.

Supported Captcha Types

The module covers all popular formats:

• Text based: Normal, Text, Audio
• Google: reCAPTCHA v2, reCAPTCHA v3, Invisible reCAPTCHA
• Cloudflare: Turnstile, Challenge
• Other providers: GeeTest, FunCaptcha, KeyCaptcha, Capy, Lemin, MTCaptcha, DataDome, Amazon WAF and many more

Full list with parameter examples is in the captcha types documentation.

Advanced Features

Async Mode with Callback

If you do not want to block code execution while waiting for a result, set up a Callback:

solver.Callback = "https://your.site/captcha-result";
await solver.Solve(captcha);
// Result will arrive as a separate POST request to the specified URL

Manual Flow Control

For complex scenarios, low-level control is available:

var taskId = await solver.Send(captcha);  // send only
// ... your logic ...
var result = await solver.GetResult(taskId);  // manual polling

Working with Proxies

Many captchas require a request from a specific IP. Pass the proxy right in the object:

captcha.SetProxy("login:pass@123.123.123.123:8000");
captcha.SetProxyType("HTTP");  // or HTTPS, SOCKS4, SOCKS5

Additional Captcha Parameters

For text and some other types, you can clarify expectations:

captcha.SetMinLen(4);
captcha.SetMaxLen(20);
captcha.SetCaseSensitive(true);
captcha.SetLang("en");
captcha.SetHintText("Enter only uppercase letters");

Error Handling

The library throws exceptions with clear messages. Always use try-catch:

try
{
    await solver.Solve(captcha);
}
catch (Exception e)
{
    // Log the error and decide: retry, notify, or fallback
    Console.WriteLine($"Failed: {e.Message}");
}

Common Error Codes

Integration Tips

• Store keys securely - use environment variables or secret managers, do not hardcode your API key
• Set timeouts for your task - complex captchas can take longer, do not set limits that are too short
• Add logging - save task IDs and response times for debugging and auditing
• Test in the sandbox - before production launch, check your integration in a test environment
• Watch your balance - set up low balance notifications to avoid downtime

Additional Resources

• Source code on GitHub - examples, issues, releases
• Full API documentation - all endpoints and parameters
• C# examples - ready snippets for each captcha type
• Error reference - explanation of all response codes
• Support - if something goes wrong

Pre-Launch Checklist

• Library installed via NuGet
• API key obtained and saved in an environment variable
• Correct captcha class selected and required parameters configured
• Timeouts and polling interval set for your load
• Exception handling and basic logging implemented
• Solution tested with real parameters from the target site
• Callback or proxy configured if needed

Conclusion

The 2captcha-csharp module is a reliable and convenient way to add captcha solving to any C# application. It hides API complexity behind a simple object-oriented interface, supports async operations, is flexible to configure, and covers all popular captcha types.

Start with basic client setup, pick the captcha type you need, and add error handling, that is enough for stable operation. And when your task grows, the library scales with you: callback notifications, manual flow control, proxies, and extended logging are all supported.

Documentation, code examples, and 2Captcha support will help you quickly handle any scenario.

Automate captcha bypass efficiently and with minimal effort using 2captcha-csharp.