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ALTCHA Spam Protection

by Daniel on WordPress.org

ALTCHA offers a free, open-source Captcha alternative, ensuring robust spam protection while respecting user privacy and GDPR compliance.

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Friction-less Captcha without puzzles

Friction-less Captcha without puzzles

ALTCHA provides a free, open-source Captcha alternative utilizing a proof-of-work mechanism to safeguard your website against spam and unwanted content. Our anti-spam solution ensures robust spam protection without compromising user privacy.

Unlike other solutions, ALTCHA is free, open-source, and self-hosted. It operates independently without external services, avoids the use of cookies and fingerprinting, refrains from user tracking, and maintains full compliance with GDPR regulations.

Privacy

No cookies, no tracking

ALTCHA prioritizes user privacy by avoiding the use of cookies and fingerprinting techniques.

No external service

Operating in Self-hosted mode (the default setting), this plugin remains fully contained within your WordPress installation, eliminating any reliance on external services. You can opt-in for our SaaS version to utilize the Spam Filter API. For more information visit https://altcha.org.

Modes of Operation

This plugin operates in two modes, you can select which mode you want in the settings (see API Region):

  • Self-hosted – fully self-contained without external services.
  • 3rd-party external service – ALTCHA’s SaaS requiring an API Key, allows you to choose EU or US region.

Note: The Spam Filter requires ALTCHA’s SaaS. Create an API Key to access it.

REST API

This plugin requires the WordPress REST API. If you are using any “Disable REST API” plugins, ensure that the endpoint /altcha/v1/challenge is allowed.

Supported Integrations

  • CoBlocks
  • Contact Form 7
  • Elementor Pro Forms
  • Enfold Theme
  • Forminator
  • GravityForms
  • HTML Forms
  • WPDiscuz
  • WPForms
  • WP-Members
  • WordPress Login, Register, Password reset
  • WordPress Comments
  • WooCommerce
  • Custom HTML (with a short code [altcha])

Source Code

All source code for the plugin, and the ALTCHA widget is available on GitHub. In the repository, you’ll also find versions of non-minified JavaScript and CSS assets:

  • Plugin: https://github.com/altcha-org/wordpress-plugin
  • ALTCHA Widget: https://github.com/altcha-org/altcha

Terms of Service And Privacy Policy for SaaS

  • Privacy Policy: https://altcha.org/privacy-policy
  • Terms of Service: https://altcha.org/terms-of-service
Active installations3K+
Weekly downloads
1,587-7.57%
Version1.25.0
Last updated8/19/2025
WordPress version5.0
Tested up to6.6.3
PHP version7.3
Tags
altchaanti-botanti-spamcaptchaspam
ALTCHA Spam Protection | Plugin0