Server-Side Rendering (SSR)

Why is server-side rendering no longer a preference?

Because no major AI crawler executes JavaScript. Vercel’s analysis of AI crawler traffic across its network, published 17 December 2024, found them requesting JavaScript files and running none: 11.5% of GPTBot’s requests were for scripts, 23.84% of ClaudeBot’s, with no rendering behind either. Googlebot renders, which is why a client-rendered site can look healthy in Search Console and be absent from every assistant.

The consequence is categorical rather than gradual. Client-rendered content is not ranked lower for these systems; it is not seen. There is no partial credit and no amount of structure, markup or writing quality that compensates.

How do you check whether yours actually works?

View source, not the inspector. The browser’s element inspector shows the DOM after JavaScript has run, which is exactly the thing these crawlers never do, so a page can look complete there and arrive empty at a crawler. The reliable check is to fetch the raw HTML and search it for a distinctive sentence from the page:

curl -s https://example.com/page | grep -q "a distinctive sentence" \
  && echo OK || echo "NOT SERVER-RENDERED"

If that fails, nothing else on any AI visibility checklist matters yet. Two traps in running it. Some frameworks serve full HTML to a request with no user agent and a shell to a browser, so check with a realistic user agent as well. And a page can be server-rendered while its most important sentence still is not, which is why the check greps for a specific sentence rather than for any text at all.

What about agentic browsers that do render?

They are real and they are a different job. Agent modes in ChatGPT, Perplexity’s browser and Claude for Chrome drive real browsers and do execute JavaScript, so a client-rendered page is readable by them. But those are per-user sessions rather than index crawls, and citation still runs on the indexes built by the non-rendering crawlers.

So the honest position is that rendering matters for one visitor at a time and server-side HTML matters for being findable at all. Building for the first and neglecting the second is optimising the rarer case. The good news is that this is one of the few AI visibility problems with a definite fix. Every modern framework can render on the server, the change is a build configuration rather than a rewrite on most sites, and once it is done the page either passes the check above or it does not.

Related terms

• AI CrawlerAn AI crawler is an automated fetcher run by an AI company to collect web pages.
• Core Web VitalsCore Web Vitals are Google’s three measurements of real-user page experience: Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness, and Cumulative Layout Shift for visual stability.
• ClaudeBotClaudeBot is Anthropic’s training crawler, documented as collecting web content that can contribute to training its models.
• ChunkingChunking is the step that splits a page into passages so a retrieval system can select one without the rest.