How React interviews scale by level

Junior interviews test whether you can build UI with hooks and manage state. Mid-level adds performance, testing, and component design. Senior interviews probe architecture, trade-offs, and how you would structure a large frontend codebase.

This guide maps expectations and preparation focus for each level.

Junior (0–2 YOE) expectations

You should confidently answer and demonstrate:

JSX, props, state, and event handling.
useState, useEffect, and useRef.
Conditional rendering and list rendering with keys.
Controlled form inputs.
Basic component composition and prop drilling.
Fetching data with useEffect and handling loading/error states.
CSS modules or Tailwind for styling.
Common question: Build a todo list, search filter, or pagination component.

Mid-level (2–5 YOE) expectations

Interviewers expect deeper hook knowledge and performance awareness:

Custom hooks for reusable logic.
useMemo, useCallback, and React.memo — when they help and when they hurt.
Context API with performance considerations.
Error boundaries and Suspense basics.
Testing with React Testing Library (render, fireEvent, waitFor).
Code splitting with React.lazy and Suspense.
TypeScript with React (props typing, generics in hooks).
Common question: Optimize a slow-rendering list or design a reusable modal system.

Senior (5+ YOE) expectations

Senior frontend interviews are half architecture, half deep technical:

State management strategy (Context vs Zustand vs Redux) with trade-offs.
Micro-frontend or monorepo architecture decisions.
Server Components and SSR/SSG strategy (Next.js context).
Design system creation and component API design.
Performance profiling and bundle optimization.
Accessibility (a11y) as a first-class concern.
Mentoring, code review standards, and frontend CI/CD.
Common question: Design a real-time dashboard or architect a multi-tenant SaaS frontend.

Cross-level topics everyone faces

These appear at every level — depth of answer scales:

Virtual DOM and reconciliation.
Component lifecycle (class legacy vs hooks).
Keys, refs, and portals.
Lifting state up vs colocation.
Side effect management and cleanup.
React 18 concurrent features overview.

Preparation by level

Junior: Build 3 small apps (todo, weather, e-commerce cart). Mid: Contribute to open source or refactor a personal project with tests and performance optimization. Senior: Write a system design doc for a frontend architecture. All levels: practice on InterviewVeda.