Cap
Lightweight open-source CAPTCHA solution using SHA-256 proof-of-work. 250x smaller than hCaptcha, fully customizable, and privacy-focused with zero telemetry.
6,781
Other
Alternative to: reCAPTCHA
Best Open Source CAPTCHA & Bot Protection
Explore open-source CAPTCHA & Bot Protection with repository signals, licensing, categories, and product details for faster software evaluation.
CAPTCHA & Bot Protection6 tools
Open-source tools
Showing 6 of 6 curated projects from this topic.
ALTCHA
ALTCHA offers cutting-edge spam and abuse protection for websites and apps, with privacy-friendly CAPTCHA alternatives designed for GDPR compliance.
2,331
MIT
Alternative to: reCAPTCHA
mCaptcha
Privacy-focused proof-of-work CAPTCHA system that silently protects websites without tracking users or requiring image solving. Drop-in replacement for reCAPTCHA.
2,445
AGPL-3.0
Alternative to: reCAPTCHA
Procaptcha
A blockchain-based CAPTCHA solution offering improved security, user experience, and resistance to bot attacks for web applications.
297
Apache-2.0
Alternative to: reCAPTCHA
Private Captcha
Privacy-first CAPTCHA service that blocks bots while keeping forms accessible. No puzzles, no tracking, no cookies - just invisible cryptographic protection.
167
Other
Alternative to: reCAPTCHA
Friendly Captcha
Privacy-compliant CAPTCHA alternative using proof-of-work technology. Protects websites from bots and spam without user interaction or data tracking.
27
MPL-2.0
Alternative to: reCAPTCHA