Next.js Deep Dive

Next.js is the production React framework SDE-2 frontend interviews expect you to know deeply, not just syntax, but rendering strategies, Server Components, and when to reach for client boundaries.

This module covers App Router file-based routing, hybrid rendering, RSC, data fetching patterns, middleware, Server Actions, and the optimizations that ship with next/image, next/font, and next/script.

Interviewers often ask where to draw the client boundary, how caching works with fetch in Server Components, and how middleware differs from client-side route guards: all covered with decision tables and code examples.

Learn file-based routing, route groups, loading.tsx streaming, generateStaticParams for SSG, dynamic rendering, Server Actions for mutations, and built-in optimizations that ship with every Next.js production app.

Phase 9 (Week 9) of the interview roadmap. Senior Track spans modules 1–19; the Staff Track starts at module 20.