UI & Frontend Prep
Prepare for frontend loops: JavaScript depth, React internals, UI coding and frontend system design.
About this course
Frontend interviews test more than LeetCode. You'll be asked to explain the event loop, build a component under time pressure, debug a performance problem, and design the client side of a product. UI & Frontend Prep covers all four.
The course starts with the JavaScript and browser fundamentals interviewers dig into, moves through React rendering and state management, and finishes with machine-coding problems and frontend system design case studies such as autocomplete, an infinite feed and a design system.
What you'll learn
- Explain closures, prototypes, the event loop and this binding with confidence
- Implement debounce, throttle, Promise.all and deep clone from scratch
- Describe how React renders, reconciles and schedules updates
- Choose a state management approach and justify it
- Build accessible, keyboard-friendly components
- Diagnose and fix Core Web Vitals and rendering performance problems
- Complete 60 to 90-minute machine-coding rounds
- Lead a frontend system design discussion from requirements to component API
Course index
10 sections · 53 lessons · 21h total · 4 free previews
- Welcome and the frontend interview loopPreview10m
- What changes between frontend and generalist interviewsPreview12m
- Study plan for 2, 4 and 6 weeks8m
Frequently asked questions
Do I need the DSA course as well?
Most frontend loops still include one algorithmic round, so we recommend pairing this add-on with DSA Prep. The rest of the loop is covered here.
Is everything taught in React?
Framework-specific lessons use React, since it's what most companies ask about. The JavaScript, browser, performance and accessibility sections are framework-agnostic.
Are TypeScript solutions included?
Yes. Every machine-coding solution is available in both JavaScript and TypeScript.
How long does it take?
About 5 to 6 weeks at 5 hours a week.
Pairs with the core courses
Most role-specific loops still include these rounds.
Data structures, algorithms and problem-solving patterns for coding rounds
143 questions · 79+ hours
Designing scalable, reliable distributed systems for architecture rounds
13 questions · 28+ hours
Storytelling, leadership and level-calibrated answers for behavioral rounds
17 questions · 15+ hours
Other add-ons
ML fundamentals, ML coding and large-scale ML system design
8 questions · 15+ hours
Linux, CI/CD, infrastructure as code and cloud platform interviews
11 questions · 13+ hours
Swift, SwiftUI, UIKit and mobile architecture interviews
8 questions · 12+ hours
Kotlin, Jetpack Compose, coroutines and Android architecture interviews
5 questions · 11+ hours
Smart contracts, Solidity, the EVM and cryptographic protocols
8 questions · 11+ hours
Ready to start UI & Frontend Prep?
JavaScript, React, browser internals and frontend architecture interviews