SEO

SEO in Next.js is the outcome of rendering mode, crawlable HTML, metadata, canonical URLs, structured data, performance, and stable URLs — not a plugin bolted on later.

Public pages should ship meaningful HTML at first response, expose clean heading structure, avoid duplicate content without canonicals, and meet Core Web Vitals budgets.

On interviews: explain how SSR/SSG/ISR choices affect crawlers and why client-only shells hurt indexing.

Common pitfalls: blocking rendering with client data fetching, infinite faceted URLs without noindex, and soft 404s that return 200.

The trade-off is marketing agility versus index hygiene and performance budgets.

Checklist:

• Crawlable HTML for public routes.
• Canonical and robots for duplicates.
• Structured data where it helps rich results.
• Monitor Search Console and vitals.