Lightweight, modern open-source CAPTCHA alternative designed using SHA-256 proof-of-work and JS instrumentation



Captoshi is described as 'Web3 startup redefining online earning through interactive math challenges' and is an website in the bitcoin & cryptocurrency category. There are more than 10 alternatives to Captoshi, not only websites but also apps for a variety of platforms, including SaaS, Self-Hosted, Google Chrome and Wordpress apps. The best Captoshi alternative is Cap Captcha, which is both free and Open Source. Other great sites and apps similar to Captoshi are reCAPTCHA, Procaptcha, IronWall and Private Captcha.
Lightweight, modern open-source CAPTCHA alternative designed using SHA-256 proof-of-work and JS instrumentation



reCAPTCHA is a free service that protects your site from spam and abuse, using risk analysis techniques to tell humans and bots apart.


Prosopo Procaptcha redefines user verification with a unique approach that emphasizes privacy and security. It's a pioneering solution designed to offer an alternative to conventional CAPTCHA systems that often compromise user privacy.




Private Captcha is an independent, privacy-first, self-hostable Proof-of-Work CAPTCHA service made in EU. Instead of asking users to solve complex puzzles or track their behavior, Private Captcha solves an invisible cryptographic task in the background.








ALTCHA is a privacy-first solution built to help developers and website owners stop bots, spam, and automated abuse — without making things harder for real users. It replaces traditional CAPTCHA systems with a smarter, quieter approach to verification and threat detection.

Turnstile is Cloudflare's smart CAPTCHA alternative. It automatically chooses from a rotating suite of non-intrusive browser challenges based on telemetry and client behavior exhibited during a session.
hCaptcha is designed to solve the most labor intensive problem in machine learning: labeling massive amounts of data in a timely, affordable, and reliable way.



mosparo is the modern solution for protecting your online forms from spam. The protection method is quite simple: mosparo blocks spam using rules matching the form’s data. The detection method is comparable to an e-mail spam filter.




Friendly Captcha is a leading cybersecurity company with a clear mission: to reliably defend against modern bot attacks and spam while complying with the GDPR and other privacy regulations. As Germany's largest CAPTCHA provider, Friendly Captcha uses innovative technology to...
