Question 1

What is required to deploy a Next.js App Router app?

Accepted Answer

A platform supporting Node (and optionally Edge), env vars, build (next build), and correct output mode. Vercel is turnkey; Node hosts need next start or adapters. Configure image optimization and caching headers.

Question 2

What is output: 'standalone' useful for?

Accepted Answer

Creates a minimal Node deployment folder for Docker/self-hosting. Copy static assets correctly. Smaller images than shipping full node_modules naively. Pair with multi-stage Docker builds.

Question 3

How do env vars work between build and runtime in Next?

Accepted Answer

NEXT_PUBLIC_* inlined at build; server env read at runtime; secrets must not use NEXT_PUBLIC_. Misusing public prefix leaks secrets. Rebuild when public env changes. Use platform secret stores.

Question 4

How do you run Next.js behind a reverse proxy?

Accepted Answer

Set trust/host configuration as needed, forward proto/host headers, and ensure asset prefixes if under subpath. Terminate TLS at proxy. Align cookie Secure flags. Test redirects don't break hosts.

Question 5

Preview deployments: what should differ from production?

Accepted Answer

Separate env, noindex, isolated data/secrets, and auth gates for private previews. Never point previews at prod writable DBs without safeguards. Use branch-specific env.

Question 6

Lead: choose Vercel vs self-hosted Kubernetes for Next.

Accepted Answer

Vercel for speed/DX/edge; K8s for control/compliance/custom networking — weigh ops cost, caching, and image optimization needs. Hybrid exists (app on K8s, assets on CDN). Decide based on team skills, regions, and regulatory constraints — not hype.

Deployment Next.js Interview Questions

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