Do AI crawlers render JavaScript?

RushilFounder, Ru Visibility2 October 2026

Short answer

Mostly not. Vercel's analysis of AI crawler traffic found that “none of the major AI crawlers currently render JavaScript”: ChatGPT's and Claude's crawlers fetch JavaScript files but don't run them. If your text only appears after JavaScript runs, those crawlers may see an empty page.

What the data showed

Vercel studied traffic from AI crawlers across the sites it hosts and published the results in December 2024. Its finding: “while ChatGPT and Claude crawlers do fetch JavaScript files (ChatGPT: 11.50%, Claude: 23.84% of requests), they don't execute them” (Vercel).

Google is different. It says it “processes JavaScript web apps in three main phases”: crawling, rendering and indexing. Even so, Google itself advises that “server-side or pre-rendering is still a great idea because it makes your website faster for users and crawlers, and not all bots can run JavaScript” (Google Search Central).

Why it matters for a business

Some website builders and apps send an almost empty page and fill it in with JavaScript in the browser. People see a full page; a crawler that doesn't run scripts sees a shell. Your services, prices and location might as well not be there.

How to check your site

Open a page, right-click and choose View page source (not Inspect). Search the source for a sentence you can see on screen. If it is there, crawlers can read it. If it isn't, it is being added by JavaScript. From a terminal you can do the same check:

curl -s https://yourdomain.com/ | grep -i "a sentence from your page"

The fix

Vercel's advice is to “prioritize server-side rendering for critical content”. In practice, make sure the text that describes your business is in the HTML the server sends. Most modern frameworks can do this; this site is built that way, so every page arrives with its text already in it.

Sources

Find out what AI says about you.

Send us your web address. We run our own tool on it, free, and send you what it says. The whole thing — not a taster with the useful bits taken out.

Whether AI can even read your site

ChatGPT, Claude, Perplexity, Google and Bing all send a small program to read your pages. We knock on your door as each one and see who gets let in. If they are being turned away, nothing else matters until that is fixed.

Two scores out of 100 — one for Google, one for AI

Plus what is behind each number. Where we could only make a fair guess, we say so instead of dressing it up as a measurement.

A list of fixes, best one first

Ordered by what gives you the most for the least work, so the top of the list is the quickest win. It is yours either way — use it with us or without us.

We ran it on our own site too. It told us what we were getting wrong, and we published that. A tool you will not point at yourself is not worth much.

One thing the free check does not do: actually ask ChatGPT, Perplexity and Gemini for businesses like yours, dozens of times, and count how often your name comes up. That costs us real money each time we run it, so it comes with paid work.