SSR · Server-side rendering
Server-Side Rendering (SSR) generates HTML on the server before sending it to the browser. It is recommended for GEO: most LLM crawlers do not render JavaScript, and content that exists only on the client side stays invisible to them.
Standalone definition · 39 words
How does SSR work?
The server runs the application, produces complete HTML with the content, then sends it. The browser displays the page immediately and hydrates the JavaScript afterward. By contrast, with client-side rendering (CSR), the initial HTML is nearly empty and the content appears after JavaScript runs.
Why does SSR matter for AI crawlers?
Googlebot renders JavaScript, with a delay. According to the Vercel and MERJ study of December 2024, the main AI crawlers tested do not execute it. A CSR site can therefore be complete for Google and empty for an AI crawler.
How do you check rendering?
View the page source (not the inspector) and look for the key content, or fetch the page with curl. If the text, headings and links are not there, a crawler without rendering will not see them. Modern frameworks offer SSR, SSG or ISR to fix this.
Frequently asked questions
SSR, SSG or ISR?
All serve complete HTML. SSG pre-generates at build time, ISR regenerates at intervals, SSR generates on demand. The choice depends on how often content changes.
Does SSR slow the site down?
It can increase TTFB. A cache or a CDN limits the effect.
Does Googlebot render all JavaScript?
It renders it, with a delay and constraints documented in JavaScript SEO basics. Better not to rely on it for essential content.
Related terms
Further reading
- Checklist GEO and LLM / AI 2026
- 2026 GEO Tools Comparison: The Decision Guide
- ← Back to the GEO glossary (114 terms)