How to Check if Search Engines and AI Crawlers Can Read Your Website
JavaScript powers much of the modern web, from navigation menus and product filters to reviews, pricing and full-page copy. Visitors see a finished page, but search engines and AI crawlers don’t always get the same view.
Google can run JavaScript, but rendering adds a delay and plenty of room for error. Most AI crawlers, including those used by ChatGPT, Claude and Perplexity, don’t run it at all. They read the HTML your server sends and nothing more. If your key content only loads through scripts, it can be missed in search results and left out of AI answers altogether.
In this blog, we’ll cover how search engines and AI crawlers handle JavaScript, how to audit your website in seven steps, and what to do with the issues you find.
What Is JavaScript Rendering?
Rendering is the process of turning a page’s code into the content a user sees. With server-rendered websites, the content arrives ready in the HTML. With client-side rendered websites, the browser downloads a basic HTML shell, then runs JavaScript to build the page.
The difference matters because crawlers don’t all behave like browsers. A JavaScript rendering audit checks whether the content, links and SEO signals on your pages are available before scripts run, after they run, or only after they run.
How Do Google and AI Crawlers Handle JavaScript?
Googlebot: Crawl, Render, Then Index
Google processes JavaScript pages in three stages. Googlebot crawls the HTML, queues the page for its Web Rendering Service to run the JavaScript, then indexes the rendered result.
Rendering isn’t always instant, so script-dependent content can take longer to be indexed. If a script errors, times out or is blocked in robots.txt, Google may index a partial page instead.
AI Crawlers: Raw HTML Only
Independent studies of crawler traffic show that GPTBot, OAI-SearchBot, ClaudeBot and PerplexityBot fetch pages without executing JavaScript. They may download script files, but they don’t run them. Google’s Gemini and AI Overviews are the main exception, as they use Googlebot’s rendering.
There are early, unconfirmed reports that this could change, but for now the safe assumption is simple: if it isn’t in your initial HTML, most AI platforms can’t read it, quote it or recommend you for it.
Warning Signs Your Website Has a Rendering Issue
- Thin indexed pages: Google has indexed the URL, but the cached or tested version is missing key copy.
- Indexing gaps in Search Console: a high number of “Crawled – currently not indexed” pages on JavaScript-heavy templates.
- Snippets that don’t match the page: titles or descriptions in search results that differ from what’s on screen.
- Hard-to-reach pages: URLs only linked through JavaScript menus, filters or “load more” buttons.
- Missing from AI answers: your brand ranks well in Google but rarely appears in ChatGPT or Perplexity responses.
How to Audit JavaScript Rendering in 7 Steps?
Step 1: View the Source Code vs the Rendered DOM
Open a key page, right-click and select “View page source”. This raw HTML is close to what AI crawlers receive. Next, open Chrome DevTools and look at the Elements panel, which shows the page after JavaScript has run.
Compare the two. Your H1, main copy, prices, product details, reviews and internal links should appear in both. Anything that only shows in the rendered version relies on JavaScript. Disabling JavaScript in DevTools and reloading the page is a quick way to confirm.
Step 2: Inspect Pages in Google Search Console
Use the URL Inspection tool, click “Test Live URL” and open “View tested page”. You’ll see the HTML Googlebot rendered, a screenshot and any resources that failed to load. If content is missing here, Google can’t index it.
Work by template rather than page by page. Test one URL for each page type, such as services, locations, blog posts and products.
Step 3: Run a Rendered and Non-Rendered Crawl
Crawl your website twice with a tool such as Screaming Frog: once in text-only mode and once with JavaScript rendering switched on. Compare word counts, headings, internal links and indexable URLs. Big differences reveal which templates depend on JavaScript and how much of the website is affected.
Step 4: Confirm Links Use Crawlable HTML
Crawlers follow links coded as standard <a href> elements. Links that rely on click events, buttons or JavaScript routing without a real URL are often ignored. Check that navigation, pagination, filters and related content links are proper anchor tags with crawlable URLs in the source code.
Step 5: Check Titles, Canonicals and Schema in the Source
Some frameworks add page titles, meta descriptions, canonical tags and structured data through JavaScript. Make sure they appear in the raw HTML, not just the rendered page. A canonical that changes after rendering sends Google mixed signals, and AI crawlers will only ever see the original version.
Step 6: Fetch Pages as an AI Crawler
First, check robots.txt. Make sure you aren’t blocking the AI crawlers you want to be visible in, such as OAI-SearchBot, GPTBot, ClaudeBot and PerplexityBot, or the JavaScript and CSS files Googlebot needs to render your pages.
Then request a page as an AI crawler would. A developer can use a command such as curl -A "GPTBot" https://www.yourdomain.co.uk/page/ to return the raw HTML served to that user agent. If your key content isn’t there, AI platforms can’t use it. Look out for firewalls and bot protection that block or challenge these crawlers too.
Step 7: Review Server Logs for Bot Activity
Server logs show which bots visit, which pages they request and what response codes they get. Filter by user agent to see how often Googlebot and AI crawlers reach your priority pages and whether they hit errors, redirects or blocked resources. It replaces guesswork with evidence.
Want to know exactly what Google and AI can see on your website? FSE Digital can carry out a full technical audit and pinpoint where JavaScript is limiting your visibility. Contact Us!
How to Fix JavaScript Rendering Problems
- Server-side rendering (SSR): the server delivers fully built HTML for every request, so all crawlers get the complete page. Frameworks such as Next.js and Nuxt support this.
- Static site generation: pages are built as HTML in advance, which works well for service pages, location pages and blog posts.
- Prerendering: bots receive a rendered HTML snapshot. Google treats dynamic rendering as a workaround, so use it as a short-term fix rather than a permanent solution.
- Progressive enhancement: deliver core content and links in the HTML, then use JavaScript to add interactivity on top.
- SEO signals in the source: output titles, meta descriptions, canonicals and schema in the initial HTML.
Once changes are live, repeat the audit to confirm your content appears in both the raw HTML and Google’s rendered view.
When to Run a JavaScript Rendering Audit?
Run an audit before and after a website launch, platform migration or theme change, and whenever you add features such as filters, review widgets or booking systems. Between those, check your main templates every quarter and keep an eye on indexing reports in Search Console.
As more customers use AI tools to research and compare businesses, rendering checks belong in every SEO audit as standard.
Get Your Website Seen in Search and AI with FSE Digital
Content that search engines and AI crawlers can’t read or can’t rank, and it can’t be recommended. At FSE Digital, our technical SEO services begin with a detailed audit of rendering, crawl-ability, indexing and site structure, followed by a clear, prioritised action plan.
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