What bots see: test your JavaScript rendering
Most search engines and AI crawlers cannot execute JavaScript. That means your React, Vue, or Angular application might look completely blank to Googlebot, ChatGPT, and LinkedIn's link previewer.
This free tool fetches your page exactly as a bot would see it - showing you the raw HTML source without any client-side rendering. Compare what humans see against what bots see, and identify content that is invisible to crawlers.
No signup needed, no software to install. Just paste your URL and discover whether your site is truly visible across the web.
How to use this tool
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Paste any URL into the input field above
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Click 'Scan this URL' to fetch the page as a bot would see it
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Review the raw HTML output - look for missing content, empty divs, or loading spinners
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Compare against your live page to identify JavaScript-dependent content
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If content is missing, consider server-side rendering or a prerendering service like PageGlass
How it works
This tool sends a server-side HTTP request to your URL using a standard bot User-Agent string. The request bypasses your browser entirely - it replicates what happens when a search engine or AI crawler visits your page.
The response is captured exactly as your server returns it: the raw HTML before any JavaScript executes. We then parse this HTML to extract key SEO elements including the title tag, meta description, Open Graph tags, canonical URL, heading structure, and structured data (JSON-LD).
Each extracted element is checked against a set of SEO best-practice rules. Missing titles, empty meta descriptions, absent Open Graph images, and other issues are flagged with a severity rating (critical, warning, or info) and an explanation of the impact on search visibility.
The tool also calculates a bot visibility score from 0 to 10 based on the completeness and quality of the content available in the raw HTML. A score of 10 means a bot can access all essential SEO elements without executing JavaScript. A low score indicates content that is invisible to non-rendering crawlers.
Why this matters for your site
When a search engine bot visits your website, it sends an HTTP request and reads the HTML response. Modern JavaScript frameworks like React, Vue, Angular, and tools like Lovable and Bolt build pages dynamically in the browser. The initial HTML response often contains just a single empty div and a bundle of JavaScript files.
While Googlebot can execute some JavaScript, it does so on a delayed schedule - sometimes days after the initial crawl. Other crawlers like GPTBot, ClaudeBot, LinkedInBot, and Facebook's scraper do not execute JavaScript at all. This means your page title, meta descriptions, Open Graph images, and actual content may be completely invisible to these platforms.
Prerendering solves this by generating a fully-rendered HTML snapshot that bots receive instead of the empty JavaScript shell. The result: your content is immediately visible to every crawler, every search engine, and every social platform that links to your site.
Frequently asked questions
What is the difference between what humans see and what bots see?▾
Humans see your page after the browser executes JavaScript, loads data from APIs, and renders the final visual layout. Bots typically see only the initial HTML response before any JavaScript runs. If your content is loaded dynamically, bots may see an empty page, a loading spinner, or just a root div element.
Does Google execute JavaScript when crawling?▾
Yes, Googlebot uses a headless Chromium-based renderer. However, JavaScript rendering is a separate phase that may happen hours or days after the initial crawl. During this delay, your content is not indexed. Additionally, Googlebot has a rendering budget - not every page gets rendered, especially on large sites.
Can AI crawlers like ChatGPT and Claude read JavaScript sites?▾
No. GPTBot (ChatGPT), ClaudeBot (Claude), and PerplexityBot do not execute JavaScript. They read the raw HTML response only. If your content is rendered client-side, these AI systems cannot access, reference, or recommend your content.
How does prerendering fix bot visibility?▾
Prerendering intercepts requests from known bots and serves a pre-generated HTML snapshot of your page. The bot receives fully-rendered content including text, meta tags, and structured data. Human visitors continue to receive your normal JavaScript application. This happens transparently with one simple change - no code modifications required.
Is this tool free to use?▾
Yes, completely free with no signup required. You can test any publicly accessible URL. For automated, always-on prerendering of your entire site, PageGlass offers simple per-site pricing.
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PageGlass renders your JavaScript pages for every bot automatically. One simple change, no code modifications, simple per-site pricing.