Rule: SSR or SSG is the DEFAULT for any content that must be indexed; CSR for indexable content is a GAMBLE whose downside lands hardest on new low-authority sites

Rule: For any content that must be indexed (marketing pages, landing pages, articles, service pages, product pages), server-side rendering or static-site generation is the default. Client-side rendering for indexable content is a gamble whose downside lands hardest on exactly the sites least able to absorb it: new, low-authority domains with no crawl-priority cushion.

CSR is acceptable only for content that does not need to be indexed — typically logged-in app views, internal dashboards, or admin surfaces.

Why: Google's render queue is real (Google two-stage processing — crawl raw HTML first; all 200-status pages queued for rendering ("a headless Chromium renders the page and executes the JavaScript") with delays from seconds to hours per Vercel/MERJ), the favourable rendering numbers come from established high-authority sites (Vercel + MERJ July 2024 rendering study — analyzed 100,000+ Googlebot fetches; 100% HTML pages rendered; median delay 10s, p75 26s, p90 ~3h, p95 ~6h, p99 ~18h; VENDOR INCENTIVE FLAGGED + high-authority test sites), the punishing numbers come from a zero-authority test subdomain (Onely November 2022 experiment (Ziemek Bućko) — brand-new zero-authority test subdomain; JS-folder page 7 took 313 HOURS vs HTML 36 hours (9x slower); first link 52h vs 25h — different stage (discovery, not render) but the high-authority/low-authority contrast is the point), and most non-Google AI crawlers do not run JS at all (Vercel + MERJ — non-Google AI crawlers (GPTBot, ClaudeBot, PerplexityBot) do NOT execute JavaScript; over 500M GPTBot fetches tracked with zero evidence of JS execution). The downside is concentrated on the population Candid serves.

How to apply: Default to Next.js / Remix / Astro / SvelteKit with SSG or SSR for marketing pages. If a contractor proposes a CSR React SPA for the public site, push back hard and verify rendered HTML via URL Inspection (Rule: in the first weeks after launch, validate RENDERED HTML via Search Console URL Inspection — confirm critical content, links, canonical, and structured data survive rendering) before shipping. Threshold to revisit: only consider CSR for indexable content once the site has strong crawl authority and rendering is verified end-to-end.