Meta Frontend Engineer Interview Questions

I would place business-critical logic where it is easiest to enforce, secure, and maintain. Presentation logic should stay in the client, but validation, authorization, and anything that must be trusted should live on the server.

I would compare the production build, environment variables, asset paths, browser support, and data shape. Many production-only bugs come from minification, stale caches, feature flags, or assumptions about data that do not hold at scale.

I would bake it into component design, code review, and testing rather than treating it as a final pass. That means semantic markup, keyboard support, focus order, and screen-reader behavior are part of the definition of done.

I would separate urgent from non-urgent events, group related updates, and give users control over frequency and visibility. The UI should make it easy to scan, dismiss, and revisit important items without turning the page into noise.

I would balance unit tests, integration tests, and a small number of end-to-end tests so the suite is both trustworthy and maintainable. The most valuable tests cover user behavior and critical workflows, not internal implementation details.