▲ Next.js
Next.js SEO Analyzer
Scan any Next.js site for framework-specific SEO issues. We detect hydration mismatches, SSR vs CSR rendering gaps, App Router metadata problems, and JavaScript-heavy pages that crawlers can't parse.
Try: vercel.com · nextjs.org · cal.com
Common Next.js SEO Issues
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Hydration Mismatch
Server-rendered HTML differs from client hydration output. Crawlers see different content than users. Caused by date/time rendering, random values, or browser-only APIs.
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Client-Only Content
'use client' components in App Router don't render server-side by default. Critical content in Client Components is invisible to crawlers.
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Missing Metadata
App Router layouts require export const metadata or generateMetadata(). Missing these means no title, description, or OG tags for crawlers.
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JS Bundle Bloat
Large JavaScript bundles increase token bloat ratio. Next.js code splitting helps, but heavy client-side packages still create excessive boilerplate.
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Dynamic Route Gaps
Next.js dynamic routes ([slug]) without generateStaticParams() may not be discovered by crawlers. Pages need internal links or sitemap entries.
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ISR Stale Content
Incremental Static Regeneration serves stale pages until revalidation. Crawlers may see outdated content, especially with long revalidation intervals.
What This Analyzer Checks
SEODiff's scanner detects Next.js sites automatically (via __next markers, _next/static paths, and Vercel headers) and runs framework-specific checks:
- JS-Trim Ratio: How much content survives JavaScript removal. Low ratio = content depends on JS execution.
- Rendering Reality: Compare static HTML vs rendered DOM. Large differences indicate hydration or CSR issues.
- Token Bloat: Measure boilerplate (nav, footer, framework code) vs actual content. Next.js sites with heavy component libraries often have 60-80% bloat.
- Meta Tag Completeness: Check title, description, canonical, OG tags, and schema.org markup.
- Internal Link Architecture: Detect orphan pages, especially dynamically generated routes missing from navigation.
See How Real Next.js Sites Score
Check the SEODiff Radar to see how popular Next.js sites perform. Compare your site against frameworks like Gatsby, Astro, and plain React: