Cap
Lightweight open-source CAPTCHA solution using SHA-256 proof-of-work. 250x smaller than hCaptcha, fully customizable, and privacy-focused with zero telemetry.
Alternative to: Cloudflare Turnstile
Best alternative software
Privacy-focused CAPTCHA alternative that protects websites from bots and spam while providing a frictionless user experience without puzzles or challenges.
Showing 6 of 6 curated projects from this topic.
Lightweight open-source CAPTCHA solution using SHA-256 proof-of-work. 250x smaller than hCaptcha, fully customizable, and privacy-focused with zero telemetry.
Alternative to: Cloudflare Turnstile
Privacy-focused proof-of-work CAPTCHA system that silently protects websites without tracking users or requiring image solving. Drop-in replacement for reCAPTCHA.
Alternative to: Cloudflare Turnstile
ALTCHA offers cutting-edge spam and abuse protection for websites and apps, with privacy-friendly CAPTCHA alternatives designed for GDPR compliance.
Alternative to: Cloudflare Turnstile
A blockchain-based CAPTCHA solution offering improved security, user experience, and resistance to bot attacks for web applications.
Alternative to: Cloudflare Turnstile
Privacy-first CAPTCHA service that blocks bots while keeping forms accessible. No puzzles, no tracking, no cookies - just invisible cryptographic protection.
Alternative to: Cloudflare Turnstile
Privacy-compliant CAPTCHA alternative using proof-of-work technology. Protects websites from bots and spam without user interaction or data tracking.
Alternative to: Cloudflare Turnstile