Sent – Messaging Infrastructure for Developers. One API for SMS, WhatsApp, and RCS across 190+ countries.

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.

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Cap

Privacy-first CAPTCHA alternative with proof-of-work

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7,496
Last commit
9 days ago
License
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:

reCAPTCHA

ALTCHA

Next-Gen CAPTCHA and Spam Protection, GDPR compliant

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2,661

mCaptcha

Privacy-first proof-of-work CAPTCHA without user friction

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2,480

Procaptcha

Decentralized CAPTCHA for enhanced web security

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296

Private Captcha

GDPR-compliant bot protection without user friction

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185

Friendly Captcha

Invisible bot protection that respects user privacy

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31

Sent

Messaging Infrastructure for Developers. One API for SMS, WhatsApp, and RCS across 190+ countries.

Get Started Free

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:

reCAPTCHA

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:

reCAPTCHA

A blockchain-based CAPTCHA solution offering improved security, user experience, and resistance to bot attacks for web applications.

Open Source Alternative to:

reCAPTCHA

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:

reCAPTCHA

Last commit

7 hours ago

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:

reCAPTCHA

Sent

Messaging Infrastructure for Developers. One API for SMS, WhatsApp, and RCS across 190+ countries.

Get Started Free