Altcha screenshot

Altcha

Author Avatar Theme by Altcha org
Updated: 21 May 2025
1211 Stars

GDPR, WCAG 2.2 AA, and EAA compliant, self-hosted CAPTCHA alternative with PoW mechanism and advanced anti-spam filter.

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Overview:

ALTCHA is a self-hosted alternative to CAPTCHA that uses a proof-of-work mechanism to protect websites, APIs, and online services from spam and abuse. It does not rely on cookies or fingerprinting, is GDPR compliant, and does not track users.

Features:

  • Frictionless CAPTCHA Alternative: Uses proof-of-work instead of visual puzzles.
  • Data Obfuscation: Safeguards email addresses from scraping.
  • Cookie-less: Designed to be GDPR compliant by default.
  • Self-hosted: Operates independently without external providers.
  • SaaS Available: Provides a SaaS API option at altcha.org/docs/api.
  • Server Integrations: Supports various server-side languages like TypeScript, PHP, and more.
  • CMS Integration: Offers a WordPress plugin and compatibility with other libraries.

Installation:

  1. Install ALTCHA by importing it in your main file:
    import altcha from 'altcha';
    
    or use the script tag to link the ALTCHA widget from the CDN:
    <script src="https://cdn.jsdelivr.net/gh/altcha-org/altcha@main/dist/altcha.min.js"></script>
    
  2. Use the <altcha-widget> tag in your forms for integration.
  3. Integrate ALTCHA with your server by following the server documentation.

Summary:

ALTCHA is a unique self-hosted CAPTCHA alternative that prioritizes user privacy, GDPR compliance, and efficiency. With features like data obfuscation, a lightweight bundle size, and various configuration options, ALTCHA aims to provide a seamless and secure solution for tackling spam and abuse on websites and online services.