RuCaptcha.dll is a .NET library designed to integrate the RuCaptcha.com CAPTCHA-solving service into C# applications with minimal effort.

Simply reference the RuCaptcha.dll file in your C# project, initialize it with your API key, and call its functions to send and solve CAPTCHA tasks.

It primarily supports image CAPTCHAs and some reCAPTCHA types, depending on what RuCaptcha.com supports.

Yes, the library itself is free to download and use. However, solving CAPTCHAs through RuCaptcha.com requires a paid balance.

RuCaptcha.dll was originally built for classic .NET Framework. Compatibility with .NET Core or .NET 5+ may require testing or wrapper adjustments.

• Limited support for advanced CAPTCHA types (like GeeTest, FunCAPTCHA).
   
• Occasional delays or lower accuracy on RuCaptcha.com during peak hours.
   
• Lack of updates or documentation from the original author (last updated years ago).

Yes, it can be used with both WPF and WinForms, as long as you're using a compatible version of the .NET Framework.

The library returns an error or null. You’ll need to handle retries or fallback logic in your application.

CaptchaAI offers broader support for CAPTCHA types (including image, reCAPTCHA V2/V3, and dynamic challenge types), faster response times, and more robust infrastructure. Unlike RuCaptcha, it’s actively maintained, with real-time support and superior reliability.

While RuCaptcha.dll is hardcoded for RuCaptcha.com, you can easily bypass this by sending the same request structure directly to CaptchaAI’s official API (https://ocr.captchaai.com/in.php) using C#’s native HttpClient. This gives you full control and avoids the limitations of the outdated DLL.