Next.js is the leading React framework, and its interviews test the thing React alone doesn't give you: rendering strategies. Server-side rendering, static generation, incremental regeneration, and now server components — knowing when to use each is the core of a Next.js interview. Here are the questions that actually get asked, with answers. (See also our React guide.)
Rendering strategies (the core)
- SSR vs SSG vs ISR vs CSR — what each is and when to use it.
- Why does Next.js exist on top of React?
- What problem does server-side rendering solve (SEO, first paint)?
- What is hydration?
App router & server components
- The app router vs the pages router.
- Server components vs client components — the difference and when to use each.
- Data fetching in the app router (async server components).
- Layouts, loading, and streaming.
Routing & features
- File-based routing and dynamic routes.
- API routes / route handlers.
- Image and font optimization.
- Middleware in Next.js.
How to prepare
Next.js rounds probe rendering and the server-component model. Practise explaining SSR vs SSG and server components out loud. Greenroom runs spoken technical interviews that follow up on your reasoning. Pair it with our React and frontend guides.
Frequently asked questions
What are the most common Next.js interview questions?
Common Next.js questions cover rendering strategies (SSR, SSG, ISR, CSR and when to use each), why Next.js exists on top of React, hydration, the app router vs pages router, server components vs client components, data fetching in the app router, layouts and streaming, file-based and dynamic routing, route handlers/API routes, image and font optimization, and middleware.
What is the difference between SSR, SSG and ISR in Next.js?
SSR (server-side rendering) generates the page HTML on each request, ideal for frequently changing, personalized data. SSG (static site generation) pre-renders pages at build time for maximum speed, ideal for content that rarely changes. ISR (incremental static regeneration) serves static pages but regenerates them in the background after a set interval, combining static speed with periodic freshness.
What are server components in Next.js?
Server components render on the server and send only the resulting HTML (and minimal data) to the client, with no JavaScript shipped for that component, which reduces bundle size and improves performance. They can fetch data directly and access server resources, but can't use browser-only features or hooks like useState. Client components, marked with 'use client', handle interactivity. You compose both for an optimal balance.
How should I prepare for a Next.js interview?
Focus on rendering strategies — knowing when SSG beats SSR, what ISR solves, and how server components reduce client JavaScript — plus the app router and data fetching, since rendering judgment is the core signal. Practise explaining which rendering mode fits a given page out loud with a voice-based mock interview that follows up.