What is server-side rendering (SSR)?

By the Variask team · Updated

Definition

Server-side rendering (SSR) means a web page's HTML is built on the server and sent complete to the browser or bot, instead of being assembled by JavaScript in the browser. It makes content readable to crawlers that do not run JavaScript.

Also called SSR, Pre-rendering

With Variask: Variask site health checks flag pages whose main content needs JavaScript to appear, along with other AI readability issues.

Why SSR matters for AI search

Googlebot can render JavaScript, but most AI crawlers fetch the raw HTML and do not run scripts. If your product details, prices or articles only appear after JavaScript runs, those crawlers see an empty or partial page, and AI assistants cannot quote it.

Options

  • Server-side rendering: HTML is built on each request.
  • Static generation: HTML is built ahead of time and served as files.
  • Hybrid frameworks such as Next.js, Nuxt and Astro mix both.
  • Prerendering services can serve rendered HTML to bots as a stopgap.

How to check your site

View the page source, not the inspected page, or fetch the URL with JavaScript turned off. If the main content is missing, AI crawlers are missing it too.

What it means for brands

  • Key content such as prices, specs, FAQs and reviews should be in the initial HTML.
  • Single page apps often need SSR or prerendering to be visible in AI search.

Questions

Server-side rendering (SSR):
common questions

OpenAI's crawlers are generally understood to read raw HTML. To be safe, make sure important content is present without JavaScript.

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