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Open Source CAPTCHA & Bot Protection Tools using GitHub

A curated collection of the best open source tools for distinguishing humans from bots (CAPTCHA) and preventing spam. using GitHub.

Privacy-first CAPTCHA alternative with proof-of-work
  • Stars


    7,928
  • Last commit


    1 day 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:

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


    2,493
  • Last commit


    1 year ago
  • License


    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:

GDPR-compliant bot protection without user friction
  • Stars


    195
  • Last commit


    1 day ago
  • License


    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


    36
  • Last commit


    1 month ago
  • License


    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:

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