Open Source CAPTCHA & Bot Protection Tools using JavaScript
A curated collection of the best open source tools for distinguishing humans from bots (CAPTCHA) and preventing spam. using JavaScript.
Privacy-first CAPTCHA alternative with proof-of-work
Stars
Stars growing over the last 30 days8,236Last commit
4 days agoLicense
Apache-2.0
Lightweight open-source CAPTCHA solution using SHA-256 proof-of-work. 250x smaller than hCaptcha, fully customizable, and privacy-focused with zero telemetry.
Open Source Alternative to:
Next-Gen CAPTCHA and Spam Protection, GDPR compliant
Stars
2,869Last commit
12 days agoLicense
MIT
ALTCHA offers cutting-edge spam and abuse protection for websites and apps, with privacy-friendly CAPTCHA alternatives designed for GDPR compliance.
Open Source Alternative to:
Privacy-first proof-of-work CAPTCHA without user friction
Stars
2,498Last commit
1 year agoLicense
AGPL-3.0
Privacy-focused proof-of-work CAPTCHA system that silently protects websites without tracking users or requiring image solving. Drop-in replacement for reCAPTCHA.
Open Source Alternative to:
Decentralized CAPTCHA for enhanced web security
Stars
303Last commit
9 hours agoLicense
Apache-2.0
A blockchain-based CAPTCHA solution offering improved security, user experience, and resistance to bot attacks for web applications.
Open Source Alternative to:
GDPR-compliant bot protection without user friction
Stars
199Last commit
3 days agoLicense
Unknown
Privacy-first CAPTCHA service that blocks bots while keeping forms accessible. No puzzles, no tracking, no cookies - just invisible cryptographic protection.
Open Source Alternative to:
Invisible bot protection that respects user privacy
Stars
37Last commit
14 hours agoLicense
MPL-2.0
Privacy-compliant CAPTCHA alternative using proof-of-work technology. Protects websites from bots and spam without user interaction or data tracking.
Open Source Alternative to:
Access control for AI agents your customers log in with
Stars
22Last commit
12 days agoLicense
BUSL-1.1
Detects AI agents using customer credentials, masks private fields, holds risky actions for passkey approval, and signs every decision on your own server.
Open Source Alternative to:
Capture – Capture screenshots, generate PDFs, scrape content, extract metadata, and automate browsers with one API.
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