rendering-strategies

SEO Technical: Rendering Strategies

Guides rendering strategy selection and optimization for search engine and AI crawler visibility. Golden rule: Page data and metadata must be available on page load without JavaScript execution for optimal SEO.

When invoking: On first use, if helpful, open with 1–2 sentences on what this skill covers and why it matters, then provide the main output. On subsequent use or when the user asks to skip, go directly to the main output.

Scope (Technical SEO)

• Static vs dynamic: SSG, SSR, ISR, CSR; when to use each
• Crawler behavior: Googlebot renders JS (with delays); AI crawlers do not
• Component-level: Content in initial HTML; tabs, carousels, nav
• Dynamic rendering: Prerender for bots when full SSR/SSG is not feasible

Rendering Methods

Method	When HTML generated	SEO	Best for
SSG (Static Site Generation)	Build time	✅ Best	Blog, docs, marketing pages; content rarely changes
SSR (Server-Side Rendering)	Request time	✅ Good	News, product pages; dynamic, personalized content
ISR (Incremental Static Regeneration)	Build + revalidate	✅ Good	Large sites; static with periodic updates
CSR (Client-Side Rendering)	Browser (after JS)	❌ Poor	Dashboards, account pages; no SEO needed
Dynamic rendering	On-demand for bots	✅ Fallback	SPAs; prerender for crawlers, SPA for users

SSG (Static Site Generation)

HTML generated at build time; same HTML for every request. Best for SEO: crawlers receive full HTML immediately; optimal performance.

• Use when: Blog, docs, marketing pages, content that doesn't change frequently
• Framework: Next.js getStaticProps, Astro, Gatsby

SSR (Server-Side Rendering)

HTML generated on each request. Good for SEO: crawlers receive complete HTML; supports dynamic, personalized content.

• Use when: News, product pages, user-specific content
• Tradeoff: Higher server load; slower TTFB than SSG
• Framework: Next.js getServerSideProps, Remix

ISR (Incremental Static Regeneration)

Static at build; pages can revalidate after a period. Good for SEO: combines static performance with freshness.

• Use when: Large sites (millions of pages); content updates periodically
• Framework: Next.js revalidate in getStaticProps

CSR (Client-Side Rendering)

Server sends minimal HTML shell; content renders in browser after JS loads. Not for SEO: crawlers may see empty content; indexing delays or failures.

• Use when: Dashboards, account pages, internal tools—no search visibility needed
• Avoid for: Public content, marketing pages, blog

Dynamic Rendering

Serve prerendered HTML to crawlers; serve SPA to users. Fallback when full SSR/SSG is not feasible (e.g. legacy SPA migration).

• How: Detect crawler user-agent; route to prerender service (e.g. Prerender.io) or headless render
• When: JavaScript-heavy sites; migration period; product/docs with CSR
• Note: Google permits this; prerendered content should match user experience

Crawler Behavior

Crawler	JavaScript	Content in initial HTML
Googlebot	Renders JS (Chrome); may have multi-day queue	Full weight; SSR/SSG preferred
AI crawlers (GPTBot, ClaudeBot, PerplexityBot)	Do not execute JS	Required—CSR content invisible
Bingbot	Renders JS	Same as Googlebot

AI crawlers: ~28% of Googlebot's crawl volume. Critical content (articles, meta, nav) must be in initial HTML. See site-crawlability for AI crawler optimization; generative-engine-optimization for GEO.

Component-Level: Content in Initial HTML

Google does not simulate user clicks (tabs, carousels, "Load more"). Content loaded via AJAX or on interaction is not discoverable.

Component	Requirement	Implementation
Tabs / Accordion	All tab content in DOM at load	Server-render; use <details>/<summary> or CSS show/hide
Carousel	All slides in initial HTML	Server-render; CSS/JS for show/hide only
Hero	Headline, CTA, LCP image in HTML	No JS-only rendering
Navigation	All nav links in first paint	No JS-injected menus for critical links

Recommendation: Server-render (SSR/SSG) all critical content; use JS only for interaction (show/hide, animation). Content loaded on click = not indexed.

Decision Guide

Content type	Rendering	Reason
Blog, docs, marketing	SSG or ISR	Best SEO; fast; static
Product, news, dynamic	SSR	Fresh content; crawler-ready
Dashboard, account	CSR	No SEO; auth required
Legacy SPA	Dynamic rendering	Bridge until SSR/SSG migration

Output Format

• Current setup: SSG, SSR, CSR, or hybrid
• Recommendation: By page type
• Component checks: Tabs, carousel, nav—content in initial HTML?
• References: Next.js Rendering, Vercel SSR vs SSG

Related Skills

• site-crawlability: AI crawler optimization; SSR for critical content; URL management
• generative-engine-optimization: GEO; AI crawlers don't execute JS
• core-web-vitals: LCP; SSR/SSG for above-fold; client-side hurts LCP
• mobile-friendly: Mobile-first indexing; content parity
• tab-accordion: Content in DOM at load; server-render tabs
• carousel: Content in initial HTML; server-render slides
• hero-generator: Hero in initial HTML; avoid JS-only
• navigation-menu-generator: Nav in first paint; no JS-only menus