How AI Leaves a Hidden Footprint in Your HTML (And How to Fix It)

Have you ever copied and pasted AI-generated content into your website’s rich text editor? You might be unknowingly leaving behind a digital footprint that exposes your use of AI—and it’s not just about the em dashes or writing style.

I recently came across a great LinkedIn post by SEO expert Bill Hartzer that dives into this exact issue. In his post, he shows how copying text from tools like ChatGPT can leave invisible code markers in your HTML that can be picked up by search engines like Google and Bing.
Read the original post here.

What’s the AI Footprint?

When you copy and paste AI-generated content directly into a CMS like WordPress or HubSpot, you may inadvertently paste hidden metadata along with it. Common examples include:

• data-start and data-end attributes in paragraph tags
• Classes like ai-optimize
• Extra inline styles or nested spans

These aren’t just harmless artifacts—they could signal to search engines that the content wasn’t written by a human. While that isn’t necessarily a penalty-worthy offense, it is a transparency issue and could impact how your content is interpreted and ranked.

How to Detect AI Footprints on a Website

Bill recommends using Screaming Frog SEO Spider and running a custom search for strings like data-start or data-end. This lets you quickly spot pages where AI content may have been pasted without cleaning.

In his example, roughly 6% of a site’s posts had telltale signs of AI content embedded in the HTML. That’s a significant number, especially if you’re managing a large site with hundreds of pages.

My Solution to Clean Up AI Footprints

If you’ve already found URLs with these issues, here’s how you can visually isolate and remove the AI residue:

1. Highlight Problematic Text in the Browser

Open your site in Chrome and enter the following code into the Developer Tools Console:

document.querySelectorAll('[data-start], [data-end]').forEach(function(el) {
  el.style.color = 'red';
});

This will highlight any text with those data- attributes in red, making them easy to spot and fix in your CMS editor.

2. Clean the HTML with a Free Online Tool

Copy your HTML source code and paste it into this cleaner:
HTML Cleaner – Remove data attributes.

• Select the option to “Remove data attributes”
• Copy the cleaned code and paste it back into your CMS

3. Always Paste Without Formatting

When pasting into a rich text field, use the “paste without formatting” shortcut to prevent copying over hidden code:

• Windows: Ctrl + Shift + V
• Mac: Cmd + Shift + V

Alternatively, if you’re working with markdown, use
this markdown-to-HTML tool to convert your text to clean, ready-to-paste HTML.

Rename AI-Generated File Names

Another subtle indicator that content was created with AI tools is the filename of uploaded assets—especially screenshots, images, or documents. Many AI tools and screen-capture software assign default file names that include random characters or references to AI usage (e.g., chatgpt-export-2024-06.html, ai_image_001.png, openai_screenshot.png).

To maintain a clean, professional presence and avoid leaving clues about your content’s origin:

• Rename files before uploading them to your CMS or media library.
• Use descriptive, SEO-friendly filenames like seo-checklist-2024.pdf or html-cleaning-example.png.
• Avoid names that include “chatgpt”, “ai”, timestamps, or other non-human-readable identifiers.

Doing so not only improves your site’s credibility but also enhances your on-page SEO through better image and asset optimization.

Final Thoughts

AI-generated content can be incredibly helpful—but if you’re not careful, the tools you use may leave behind a hidden signature that search engines can detect. With just a few extra steps, you can make sure your content is clean, optimized, and human-like in both appearance and structure.

Thanks again to Bill Hartzer for the insightful tip. It’s a good reminder that what you paste is just as important as what you publish.