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
revalidateingetStaticProps
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