Next.js 15 has fundamentally changed the SEO landscape for React developers. With the App Router, we've moved away from the Head component to a powerful, server-side Metadata API.
#The Metadata API
Static metadata is easy, but real-world apps have dynamic content. The generateMetadata function is your new best friend.
#Dynamic Sitemaps
Next.js 15 supports a sitemap.ts file in your app/ directory that generates a valid XML sitemap at build time.
#Core Web Vitals Mastery
• LCP: Use the <Image priority /> prop for above-the-fold hero images.
• CLS: Never serve an image without dimensions.
• INP: Move logic to Server Components to keep the main thread idle.