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RenderPeek · a free tool from mod_pagespeed

See what AI crawlers miss. Optimize the HTML you serve, on your own servers.

Most AI crawlers read your raw HTML and never run your JavaScript, so anything your scripts render is invisible to them. Paste a URL to see the gap. The same self-hosted mod_pagespeed worker that powers this site then optimizes and cleans that HTML inline, on your own servers rather than behind a CDN. The optimizer worker can also serve AI agents a clean, rendered copy of the page at the same URL — an experimental feature, off by default, that we dogfood here.

Free · no signup · one page at a time · renders your page in a headless browser (~5–10s).

Only scan sites you own or are authorized to test. Scanned content is used only to produce this readability result and is not retained or shared beyond that. Your IP address is logged and rate-limited to 20 requests per minute per visitor to prevent abuse. See our Privacy policy.

Free · no signup · one page at a time · usually under a minute.

Only check sites you own or are authorized to test. The URL goes to Google's PageSpeed Insights API (in the US) through a proxy on this site, and our scanner (also in the US) requests the page a few times: once in a headless browser and a few times as plain requests. The result, including a shareable link, is kept for up to 24 hours. Scanned content is used only for this result. We log your IP address and rate-limit requests per address to prevent abuse. See our Privacy policy.

This tool calls Google's public PageSpeed Insights API. mod_pagespeed 2.1 is developed by We-Amp B.V. and is not affiliated with or endorsed by Google. PageSpeed Insights is a trademark of Google LLC.

From We-Amp — the team behind ngx_pagespeed.

Can AI crawlers execute JavaScript?

Most do not. GPTBot, ClaudeBot and PerplexityBot fetch your raw HTML and do not run your scripts; Google’s stack, which renders pages for Gemini through Googlebot, is the exception. When we rendered the top 1,000 sites on 28 May 2026, 403 of the 711 we could read at all (57%) showed a non-rendering agent a nearly empty page: their content appeared only after JavaScript ran. Read the full results.

Which AI crawlers render JavaScript?

The major AI crawlers fetch your raw HTML and do not run your scripts. Only Google’s stack renders JavaScript today. This reflects crawler behavior in 2026 and can change, so re-scan to confirm what an agent sees now. We measured the same rendering gap across the top 1,000 sites — see what we found.

Crawler Used by Renders JavaScript?
GPTBot ChatGPT No — static HTML only
ClaudeBot Claude No — static HTML only
PerplexityBot Perplexity No — static HTML only
Googlebot Google / Gemini Renders JS

Frequently asked questions

Can AI crawlers read JavaScript-rendered content?

Most cannot. GPTBot (ChatGPT), ClaudeBot, and PerplexityBot fetch raw HTML and do not execute JavaScript, so content that only appears after your scripts run is invisible to them. Google’s Gemini is the exception — it reuses Googlebot’s rendering.

Which AI crawlers render JavaScript?

As a rule, only Google’s stack (Gemini via Googlebot) renders JavaScript. GPTBot, ChatGPT-User, ClaudeBot, and PerplexityBot read static HTML only. If your content is client-rendered, those agents see a near-empty page.

How do I check what an AI crawler sees on my page?

Disable JavaScript and reload — what remains is roughly what a non-rendering crawler reads. Or paste your URL into the scanner above: it shows the raw-HTML vs rendered token counts side by side.

How do I make my site readable to AI agents?

Serve the meaningful content in the initial HTML response (server-side rendering or pre-rendering). A self-hosted optimizer like mod_pagespeed reduces page weight and cleans markup, which helps both browsers and machine readers.

Does llms.txt make my site AI-readable?

No. llms.txt is an optional hint file; it does not fix content that is invisible because it requires JavaScript to render. Readability still depends on the content existing in the HTML the agent fetches.

Docs: Serve Markdown to AI agents, Verify AI crawlers with Web Bot Auth and Validate RSL license capability tokens.

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