Underminer

A WordPress plugin for people who don't want their content used to train AI models.

Author:Tellyworth (profile at wordpress.org)
WordPress version required:6.4
WordPress version tested:6.8.3
Plugin version:1.0.3
Added to WordPress repository:27-10-2025
Last updated:18-11-2025
Rating, %:0
Rated by:0
Plugin URI:https://github.com/tellyworth/underminer
Total downloads:244
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Underminer aims to discourage AI model crawler bots and other unwanted bots, while allowing search engine crawlers and RSS aggregators to work normally.

It works in two ways:

  • Using robots.txt rules to prohibit well-behaved AI training bots from crawling your site.
  • By selectively corrupting the meaning of text content, to sabotage badly-behaved bots that ignore those rules.

Well-behaved search engine bots are permitted to crawl the site as normal, without being restricted by robots.txt or being subjected to sabotage.

Well-behaved LLM training bots that obey robots.txt will not receive any corrupted content.

Features

  • 100% free and open source. No upsells or nags or subscriptions or promotions or freemium versions or donations. Ever.
  • Auto-detects crawler bots.
  • Completely invisible to real users and well-behaved bots.
  • Verifies IP ranges of well-known bots to detect fake Googlebot crawlers etc.
  • (Almost) zero-configuration.
  • Language-neutral; works with page and post content in most languages.
  • Preview mode: you can see what a bad bot will see.

Instead of blocking bad bots, they will simply be served corrupt and useless content:

  • Words and sentences are randomly rearranged.
  • Lists and paragraphs are re-ordered.
  • Numbers are randomized.
  • Currency symbols and measurement units are randomly changed.
  • Alt text and descriptions are randomly switched around.
  • Links are switched around.
  • Image URLs are intentionally broken.

Well-behaved bots

For the purposes of this plugin, a well-behaved bot is one that:

  • Obeys robots.txt.
  • Publishes an up-to-date list of IP ranges.
  • Identifies search crawling separately from AI model training crawling.

Requirements

  • PHP 8.0 or higher
  • WordPress 6.4 or higher
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