Technologies Coding Problems Bookmarks Learning Paths

Technologies Coding Problems Bookmarks Learning Paths

AI-powered interview preparation platform. Practice with curated questions, mock interviews, and personalized learning paths to crack your dream tech interview.

Quick Links

Technologies
Saved Questions
Pricing

Company

About Us
Contact Us

Legal

Privacy Policy
Terms of Use

© 2026 nextRound. All rights reserved.

What is Hot Module Replacement? | HMR | Webpack Interview Questions | NextRound.in

Questions

1 of 1

1What is Hot Module Replacement?

Webpack

01 / 01

What is Hot Module Replacement?

Difficulty: 5/10

development workflow, webpack configuration, state handling

Hot Module Replacement (HMR) exchanges, adds, or removes modules while an application is running, without a full reload. This can significantly speed up development in a few ways:

1
Retain application state which is lost during a full reload.
2
Save valuable development time by only updating what's changed.
3
Instantly update the browser when modifications are made to CSS/JS in the source code, which is almost comparable to changing styles directly in the browser's dev tools.
4
HMR is an opt-in feature that only affects modules containing HMR code.

Scenario Questions

0-2 years experience

1You're adding a new React component to a project that uses Webpack with HMR enabled. How would you verify that changes to this component are hot‑reloaded without a full page refresh?
2If you modify a CSS module while HMR is running and the styles don't update, what steps would you take to troubleshoot the issue?

2-5 years experience

1During development you notice that after updating a module, the application crashes and HMR falls back to a full reload. Walk me through how you'd diagnose why HMR failed.

Follow-up Questions

What are common reasons HMR might silently fail?
How does HMR interact with global state libraries like Redux?
When would you choose to disable HMR for a particular module?

Sharethis question

Share via WhatsApp, X, Facebook, LinkedIn or copy link. Open Graph preview enabled.

2You need to add a third‑party library that doesn't support HMR out of the box. How would you configure Webpack to make it work, and what trade‑offs would you consider?

5-8 years experience

1Our large monorepo uses Webpack with HMR across multiple micro‑frontends. What architectural concerns arise with state synchronization and module boundaries, and how would you mitigate them?
2Explain how you would instrument performance monitoring to ensure HMR updates stay under a latency threshold, and what fallback strategies you'd implement if they exceed it.

8+ years experience

1We are planning to migrate a legacy codebase that currently relies on full page reloads to a HMR‑enabled development pipeline. What cross‑team processes, tooling changes, and long‑term maintenance considerations would you address?
2Discuss the implications of enabling HMR in production builds for a SaaS platform, including security, bundle size, and CI/CD impacts, and decide whether to adopt it.