React Developer Interview Questions for Indian Companies 2026

Hooks are the highest-frequency topic in Indian React interviews. You need to go beyond definitions.

useState: when does a state update trigger a re-render? How do you batch multiple state updates? Common trap: why does logging state immediately after setState show the old value?

useEffect: dependency array rules, cleanup functions, when to use an empty array vs specific deps. Classic interview question: 'What is the problem with putting an async function directly inside useEffect?'

useRef: two uses: accessing DOM nodes and storing mutable values that should not trigger re-renders. Common question: 'How would you debounce a search input without re-rendering on every keystroke?': the answer uses useRef for the timer.

useCallback and useMemo: when do they help vs when do they hurt? The answer involves understanding reference equality and React's reconciliation.

State management beyond useState is a common topic at companies with complex UIs.

Context API: performance implications of putting large state in context: every consumer re-renders on any change. How to optimise: split context into smaller pieces or use a selector pattern.

Redux Toolkit: the standard in larger Indian product companies. Know createSlice, createAsyncThunk, and the RTK Query pattern. Immer's role in allowing 'mutating' immutable state.

Zustand: increasingly popular at Indian startups for its simplicity. Know the basic store creation and the selector pattern to prevent unnecessary re-renders.

Common interview question: 'When would you use Context API vs Redux vs Zustand?': the answer centres on complexity, team size, and whether you need devtools or time-travel debugging.

Performance questions appear in senior and mid-level React interviews at Indian product companies.

Re-render prevention: React.memo, useCallback, useMemo: and why overusing them can make code slower. Lazy loading: React.lazy + Suspense for code splitting; dynamic import() for heavy libraries. Virtual list: when you render 10,000 items, use react-window or tanstack-virtual. Profiler tool: know how to use the React DevTools Profiler to find which component is re-rendering most. Common question: 'Your component re-renders 50 times during a 2-second animation: how do you diagnose and fix it?'

Senior-level interviews ask about component design and architecture decisions.

Component composition patterns: compound components, render props, higher-order components: know when each is appropriate. Custom hooks: extracting logic into reusable hooks is a standard expectation for mid-level engineers. Folder structure: feature-based vs type-based: be ready to discuss trade-offs. Common question: 'Design the component architecture for a multi-step form with validation, where each step can be independently navigated.'

The depth of React interviews varies significantly by company type in India.

Flipkart/Meesho/Swiggy: heavy on performance: bundle size, lazy loading, Core Web Vitals. They care about real-user impact at scale. Razorpay/PhonePe: accessibility and cross-browser compatibility matter: payment UIs must work on low-end Android WebViews. Startups (Series A–C): expect to build a small component live in CodeSandbox: debounced search, infinite scroll, or a custom dropdown. Service IT companies (rare React depth): usually stop at hooks and lifecycle methods.