hCaptcha

Imunify360 is a comprehensive security platform designed for Linux web servers. It utilizes machine learning technology and other advanced techniques to provide robust protection against various cyber threats, including malware, viruses, and other types of attacks, ensuring the integrity and performance of web hosting environments.

Cloudflare Turnstile is a smart CAPTCHA alternative designed to provide a more user-friendly and privacy-focused approach to bot detection. It uses non-interactive challenges and machine learning to validate users without requiring them to solve puzzles or identify objects.

Friendly Captcha is an innovative proof-of-work based CAPTCHA alternative where the user's device performs computational work to prove humanity. This approach provides effective bot protection while offering a seamless, accessible user experience without traditional CAPTCHA challenges.

Slider Captcha is a free service that helps protect websites from spam and abuse.

DDoS-Guard is a Russian Internet infrastructure company that provides a range of services including DDoS protection, content delivery network (CDN) services, and web hosting. Their solutions help websites and online services maintain availability and performance in the face of distributed denial-of-service attacks.