What Can LLMs Actually Read on Your Website?

Most brands think they know what their website looks like.

But what matters in 2025 is what LLMs can see, not what your browser shows you after all the scripts have run.

If your content is hard for models like ChatGPT, Claude, Rufus, Gemini and Perplexity to read, you are invisible at the exact moment shoppers are asking questions that should lead to your product.

And the surprising bit:

A huge chunk of modern websites are very hard for LLMs to read in a reliable way.

Here’s a simple way to see how dependent you are on JavaScript, and what to do next.

The One-Minute Sanity Check

This is not a perfect simulation of how every crawler works, but it is a fast way to see how much of your site exists before JavaScript runs.

- Open your site in Chrome
- Right-click → Inspect (or press Cmd+Option+I on Mac / Ctrl+Shift+I on Windows) to open DevTools
- With DevTools open, press the Command Menu shortcut:
- Mac: Cmd+Shift+P
- Windows: Ctrl+Shift+P
- A search box appears at the top of DevTools. Type: Disable JavaScript
- Click the “Disable JavaScript” option that appears (or hit Enter when it’s highlighted)
- Keep DevTools open and refresh the page (Cmd+R / Ctrl+R)
(to put it back do the same but "enable Javascript")

What loads next shows you how much of your page is there without JavaScript.

If a lot disappears, you are heavily JS-dependent.

That is your first signal.

Why this test matters (and what it doesn’t tell you)

Most LLMs lean on HTML and structured data. Many do not fully execute every script on every page they ingest.

So if:

Your product information only appears after a JS framework renders it
Your PDP content is loaded via async calls
Your “experience layer” is a shell without JS
…then simpler crawlers and some LLM pipelines will see a much thinner version of your site.

However, the “disable JavaScript” view is only a diagnostic, not the full truth. LLMs can still learn about you from:

Your raw HTML (even if the page looks plain)
JSON-LD structured data (Product, FAQPage, Organisation, etc)
Sitemaps and feeds
Retailers, marketplaces and review sites that carry your data

So if the page looks empty with JS off, don’t panic. Treat it as a prompt to check what your HTML and structured data are actually exposing.

Step Two: Check What the HTML Really Contains

Pick one key page, ideally a product detail page or category page.
Load it normally (with JavaScript enabled).
Right-click and choose View page source.

In the source, look for:

Real text content
Product titles, descriptions, features, headings, bullet points.

Structured data blocks