Deployment and Production React Interview Questions

Deployment and Production React Interview Questions

Deployment and production knowledge come up in interviews, especially for mid-level and senior roles. Here are the common questions.

How do you deploy a React app?

Run npm run build to create the production bundle, then deploy to a host like Vercel, Netlify, or Firebase Hosting. Set environment variables in the dashboard, and configure SPA routing so deep links work.

What is the difference between dev and production builds?

Dev builds keep readable code, source maps, and hot reload. Production builds minify code, remove development warnings, and optimize for size and speed. Users load less and faster with a production build.

How do you handle environment variables in production?

Set them in the hosting platform's dashboard, not in committed code. Remember that frontend env vars are visible to users, so real secrets go in a backend, not in React.

Why do React routes break after deployment and how do you fix it?

Because the host serves 404 for routes that are not files. Fix by redirecting all routes to index.html with a rewrite rule, so React Router handles them client-side.

What would you check before shipping a React app to production?

Production build succeeds, bundle size, environment variables, error boundaries, loading and error states, auth in production, responsiveness, and accessibility. A production app is held to a higher bar than a dev one.

How to Answer Well

Show you understand the gap between dev and production. Interviewers want to hear that you know production has its own concerns: builds, env vars, routing, error boundaries, and real testing on the deployed app.

The Takeaway

Know how to deploy, dev vs production builds, how to handle env vars, why routes break and the fix, and what to check before shipping. Frame answers around the gap between dev and production.