How can you minimize bundle size in React applications?

0-2 years experience

1. 1You have a React app created with Create React App and the production bundle is 1.5 MB. What concrete steps would you take right now to shrink it before the next release?
2. 2If you notice that importing a utility library brings in the entire library, how would you rewrite the import to keep the bundle small?
3. 3How does using a named export instead of a default export affect tree‑shaking in a typical bundler?

2-5 years experience

1. 1Your team added a new charting library and the bundle grew by 400 KB, causing a performance regression. Walk me through how you’d investigate the cause and what you’d do to mitigate the impact.
2. 2We need a heavy component to load only when a user navigates to a specific route. Explain how you’d implement code‑splitting for that route and what trade‑offs you’d consider.
3. 3During a release the production bundle size increased unexpectedly even though no new features were merged. How would you debug and pinpoint the source of the bloat?

5-8 years experience

1. 1Design a strategy to keep the bundle size under 500 KB for a large React application used by multiple teams. Discuss tooling, architecture, and ongoing monitoring you’d put in place.
2. 2Explain how you’d configure Webpack (or Vite) to enforce strict tree‑shaking and eliminate dead code in a monorepo with shared packages, and what edge cases you watch out for.
3. 3When the app uses server‑side rendering, how does bundle‑size optimization differ, and which techniques would you apply to ensure a fast initial load?

8+ years experience

1. 1Our organization is consolidating several legacy React apps into a single micro‑frontend platform. How would you establish a bundle‑size governance model that scales across teams, including CI checks, shared library policies, and versioning strategies?
2. 2Compare the trade‑offs of shipping a large monolithic bundle versus multiple federated modules using Module Federation, focusing on long‑term maintainability, performance, and team autonomy.
3. 3Describe how you’d lead a cross‑team effort to replace heavyweight UI dependencies with lighter alternatives while ensuring backward compatibility and minimal disruption.