nextjs

Next.js enables server-side rendering through the App Router and Server Components, which fetch data on the server and send pre-rendered HTML to the client. This approach reduces JavaScript sent to browsers and improves initial page load performance while maintaining dynamic interactivity with Client Components where needed.

Server Components run only on the server, accessing databases and APIs securely without exposing credentials to browsers, while Client Components run in the browser and handle interactivity. Next.js automatically optimizes which components render where, reducing bundle size and improving security.

Next.js provides Server Actions for form handling directly within components and API routes for building endpoints. Server Actions execute on the server, securing sensitive logic and database operations, while API routes follow REST patterns for external clients or complex endpoint needs.

Yes. Next.js combines SSG with revalidation strategies—time-based (ISR) regenerates pages at intervals, on-demand revalidation updates pages when data changes. This lets you pre-render high-traffic pages for speed while keeping dynamic content fresh without server requests per visitor.

TypeScript is optional but recommended. Next.js has built-in TypeScript support with zero configuration, automatically detecting `.ts` and `.tsx` files. Using TypeScript catches type errors early, improves IDE autocompletion, and makes server and client code safer without extra build setup.

The App Router uses a file-system based structure where folders represent routes and `page.tsx` files define route content. Special files like `layout.tsx` declare persistent UI, `loading.tsx` shows pending states, and `error.tsx` handles errors—creating a declarative, cohesive structure with nested layouts and error boundaries built in.