Next.js and React serve different purposes: React is a UI library focused solely on component rendering, while Next.js is a framework built on React that adds file-based routing, server-side rendering (SSR), static site generation (SSG), incremental static regeneration (ISR), API routes, and Server Actions. The post explains React's component and hook model, what it deliberately omits (routing, SSR, data fetching conventions), and how Next.js fills those gaps. Key differences covered include routing (manual React Router vs. file-system routing), rendering modes (CSR-only vs. SSR/SSG/ISR/CSR mix), SEO implications, and full-stack capabilities via Route Handlers and Server Actions. Guidance is provided on when to use each: plain React suits authenticated internal tools and SPAs without SEO needs, while Next.js fits public-facing apps, content-heavy sites, and full-stack projects where server rendering and collocated API routes matter.
