server-side rendering
Also called: SSR, server side rendering
Server-side rendering (SSR) is when the server builds a page's full HTML and sends it to the browser ready-made, instead of shipping an empty shell plus JavaScript that assembles the page in the browser. Users and search engines then get complete content on the first request.
Server-side rendering sits opposite client-side rendering (CSR), where the server sends a minimal HTML document plus JavaScript and the browser assembles the page. With SSR, that work happens on the server, so the response already contains the title, headings, copy, links, and structured data.
Why it matters for indexing
Google processes JavaScript in three phases: crawling, rendering, and indexing. Pages that return a 200 status get queued for rendering, and per Google that page “may stay on this queue for a few seconds, but it can take longer than that.” A headless Chromium then executes the JavaScript. SSR skips that wait. The content is already present on the first crawl pass, so nothing depends on a second rendering step.
The tradeoff is server speed. web.dev notes that “generating pages on the server takes time, which can increase your page’s TTFB.” Static rendering (prebuilt HTML served from cache) avoids that cost. Hydration then runs client-side scripts on top of the server HTML to add state and interactivity.
Google’s own guidance is to use SSR for content-driven sites and reserve CSR for interactive tools, rather than forcing one approach everywhere. Google also points out that “not all bots can run JavaScript,” which matters as more of your traffic and citations come from AI crawlers that read raw HTML.
How it affects your traffic
If your pages only assemble in the browser, Google can index an empty shell or defer the real content until a later rendering pass, and anything that appears only after JavaScript runs may be missed entirely by AI crawlers that read raw HTML. That is lost rankings and lost AI citations on pages you already paid to build. Choosing SSR (or prerendering) for content pages puts the full page in front of every crawler on the first request. A Technical SEO audit is where we check how your site actually renders to crawlers and fix the gaps.
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