Next.js Interview Questions

Next.js is a React framework: it uses React for the UI layer but adds the tooling, structure, and optimizations needed to build a full-stack, production-ready application. Plain React with Vite gives you a client-rendered SPA, a fast dev server, and HMR, but you have to bring your own router, data-fetching strategy, bundler configuration, and rendering strategy. Next.js bundles all of that in: file-system based routing, multiple rendering modes (server rendering, static generation, incremental static regeneration), a compiler (Turbopack/webpack under the hood), built-in image/font/script optimization, and - via the App Router - React Server Components and Server Actions, so you can write server-side data-fetching and mutation logic directly in your components without hand-building an API layer. The practical distinction interviewers look for: Vite+React ships a JS bundle that renders everything in the browser; Next.js can render on the server (or at build time) and send HTML to the client, which helps with SEO, initial load performance, and colocating backend logic with UI.