altcha
A self-hosted, privacy-first CAPTCHA alternative using proof-of-work to protect websites and APIs from spam without tracking.
What is altcha?
ALTCHA is a self-hosted, privacy-first security solution that protects websites, APIs, and online services from spam and abuse through an innovative proof-of-work mechanism. It eliminates the need for intrusive methods like cookies or fingerprinting by using background proof-of-work calculations, offering robust protection while respecting user privacy.
Developers and organizations building websites, APIs, or online services that require spam and abuse protection, especially those with strict privacy (e.g., GDPR, HIPAA) and accessibility (e.g., WCAG 2.2 AA) compliance requirements.
Developers choose ALTCHA for its unique combination of being fully self-hosted, privacy-by-design with no tracking or data collection, and its frictionless user experience that avoids visual puzzles. Its hardware-resistant algorithms (Argon2 and Scrypt) provide strong security against bot farms while maintaining a minimal bundle size significantly smaller than alternatives like reCAPTCHA.
Overview
GDPR, WCAG 2.2 AA, and EAA compliant, self-hosted CAPTCHA alternative with PoW mechanism.
Use Cases
Best For
- Protecting form submissions and APIs from spam and automated bots without using cookies or fingerprinting.
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