active

60h estimated105 questions

Senior Frontend

Architecture, performance engineering, security, and system design. The bar for senior+ roles at top-tier product companies.

Performance

Bundle optimisation, CWV, virtualization.

60 questions

Easy

Big list rendering: windowing and virtualization3m

Hard

Build a reusable UI component with focus on modularity, performance, and design tradeoffs3m

Medium

Code splitting and lazy loading — how they improve performance6m

Medium

Code splitting strategies — route, component, vendor6m

Easy

Debouncing vs throttling — when to use which5m

Easy

Difference between SSR and CSR3m

Easy

Explain lazy loading vs preloading vs prefetching6m

Medium

Explain Web Performance Metrics3m

Hard

Frontend system design fundamentals (component structure, state, performance)3m

Hard

Frontend system design: Performance, SSR, and SEO3m

Medium

How can you do caching on a website3m

Medium

How do you explain frontend performance metrics (like TTI, FCP, CLS) to non-technical stakeholders3m

Medium

How do you handle bundle analysis and optimization3m

Medium

How do you measure and quantify the impact of a performance fix3m

Medium

How do you measure performance in real-world projects3m

Medium

How do you optimise bundle splitting3m

Medium

How do you optimize Core Web Vitals?9m

Medium

How do you optimize web performance and reduce load times3m

Medium

How do you prevent XSS and CSRF attacks3m

Medium

How do you reduce bundle size in production?8m

Medium

How do you reduce Time to Interactive (TTI)?7m

Medium

How thunk-based API calls work and how caching behaves3m

Medium

How to cancel previous API requests3m

Medium

How unnecessary re-renders happen and how to avoid them3m

Medium

How would you build maps.google.com (tile loading, performance, UI responsiveness)3m

Hard

How would you design a system to handle client-side caching, API retries, and error boundaries gracefully3m

Medium

How would you implement dynamic theming (light/dark mode) in a large web application without performance issues3m

Medium

How would you manage performance if the undo stack gets large3m

Easy

HTTP caching strategies3m

Medium

If an API returns 5000 records, how do you display them efficiently in a dropdown?7m

Medium

Image optimization techniques on the frontend6m

Easy

Infinite scroll, virtual list — what's the performance model3m

Easy

Lazy loading with image optimization6m

Medium

Memoization to reduce re-renders7m

Medium

Optimize performance for scale3m

Medium

Optimize rendering for a list of 10,000 items7m

Medium

Optimizing third-party script loading7m

Easy

Performance topic: CDN + asset optimization3m

Easy

Performance topic: Code splitting and dynamic imports3m

Easy

Performance topic: Debounced inputs3m

Easy

Performance topic: Virtualization3m

Medium

Performance, SSR, and SEO — what matters and how they interact3m

Easy

Preload, prefetch, and lazy loading3m

Medium

preload, prefetch, preconnect, dns-prefetch — what's the difference?6m

Medium

Reducing reflows and repaints7m

Medium

Repaint vs reflow (layout) vs composite — what triggers what?7m

Medium

SSR vs SSG vs CSR — when to use each?7m

Medium

Tree shaking and bundling — how do they work?6m

Medium

Web Vitals — what actually matters (LCP, INP, CLS) and how to optimize each7m

Easy

What are Preload, Reconnect, Prefetch, and Prerender3m

Easy

What are resource hints (preload, prefetch, dns-prefetch, preconnect)3m

Medium

What challenges have you faced when building for large user traffic3m

Easy

What does the Next.js <Image> component do that a plain <img> doesn't?6m

Medium

What is lazy loading and how to implement it3m

Easy

What is Service Worker3m

Easy

What performance metrics do you track in production3m

Easy

What techniques would you use to ensure performance and responsiveness3m

Medium

What would be your approach for handling the drag events, and how would you optimize performance3m

Medium

When function declarations vs arrow functions impact performance3m

Medium

When would you use virtualization?7m

System Design

Scaling, micro-frontends, modular apps.

26 questions

Easy

Build a Phone Screen–style web app (LLD)5m

Hard

Build a real-time order tracker with WebSockets10m

Hard

Design a calendar UI like Google Calendar11m

Hard

Design a Jira-style 3-column Kanban board (open / in-progress / done)12m

Hard

Design the frontend for a real-time collaborative dashboard9m

Hard

Designing a frontend feature flag system10m

Hard

Designing an offline-first frontend10m

Hard

Explain the concept of component-driven architecture.3m

Hard

Frontend architecture: Code splitting3m

Hard

Frontend architecture: modular applications9m

Hard

Frontend architecture: Pure functions & testable code3m

Hard

Frontend architecture: Routing strategy3m

Hard

Frontend architecture: Scenario-based discussion on past projects, ownership, and decision-making.3m

Hard

Frontend architecture: State management layers3m

Hard

Frontend architecture: Web Workers (what problems they actually solve)3m

Hard

Frontend architecture: Whiteboard round — APIs, data modeling, scalability, trade-offs.3m

Medium

How do you manage shared dependencies in a monorepo3m

Medium

How would you build a scalable chat UI for an LLM-powered product3m

Hard

How would you design a frontend architecture that can handle 1M+ users daily3m

Hard

How would you design a realtime scalable gaming dashboard3m

Medium

How would you implement feature flags safely?8m

Hard

How would you structure a scalable frontend app with 100+ pages?10m

Hard

Micro-frontends — independent deploys10m

Hard

Started with an in-depth discussion on my project responsibilities and architecture was asked to illustrate the overall project flow using a diagram3m

Hard

Walk me through your role designing a frontend architecture3m

Hard

What is Microfrontend architecture? Explain with a real-world use case3m

Security

XSS, CSRF, cookies, auth flows.

13 questions

Medium

Asked how I approach secure storage handling (localStorage / sessionStorage)3m

Easy

Build a Security awareness (XSS, safe rendering)3m

Medium

CSRF and token refresh flow9m

Medium

How do you call and handle responses from AI APIs like OpenAI, Hugging Face, or Google Cloud AI3m

Medium

How do you handle privacy and security for AI-powered data3m

Medium

How do you handle rate-limiting or large payloads when consuming AI services3m

Medium

How do you implement Role-Based Access Control on the frontend?7m

Medium

How do you secure your application from attacks3m

Medium

JWT vs session cookies8m

Medium

Prevent XSS in React apps8m

Easy

What breaks if the merchant's CSP restricts inline scripts or frame-src3m

Medium

Why are HttpOnly cookies preferred for auth?7m

Easy

Write a function that safely serializes user input before it touches the DOM, probing XSS awareness in payment forms.3m

Architecture

Design systems, monorepos, state strategy.

1 question

Hard

How would you design a reusable component library across teams?10m

Accessibility

WCAG, ARIA, keyboard navigation.

5 questions

Easy

Build a modal component (focus trap, ARIA)7m

Medium

Frontend accessibility basics — what every interview expects you to know7m

Medium

Handle accessibility, how should screen readers announce new toasts6m

Medium

How would you ensure accessibility (e.g., screen readers)6m

Medium

What are web accessibility standards (WCAG) and how do you implement them6m