Cars24 Frontend Interview Experience

Note: This interview experience was contributed by a user of devtools.tech platform. You can contribute your interview experiences here and interview questions here.

Overview

The interviews focused heavily on JavaScript fundamentals, React development, machine coding, and performance optimization. Evaluated through a combination of conceptual discussions, output-based questions, practical coding exercises, and system design discussions.

Interview Process

The process typically consisted of 3–4 rounds:

1. JavaScript Fundamentals Round
2. Machine Coding / React Implementation Round
3. Hiring Manager / Techno-Managerial Round
4. System Design
5. HR / Culture Fit Round

The difficulty and depth increased with seniority.

Round 1: JavaScript Fundamentals

This round primarily focused on core JavaScript concepts, output-based questions, and small coding implementations.

Topics Covered

Hoisting and Temporal Dead Zone: Sharing some example questions:

• What is the output of the following code snippet? | JavaScript Output Based Question | JS Variables
• What would be the output? (Based on Temporal Dead Zone)

Closures

Discussion around closures and implemented examples demonstrating how inner functions retain access to outer variables.

Explore Closures based questions: https://devtools.tech/questions/all?categories=closures

Currying

• Implement Currying

this Keyword and Context

Questions tested understanding of:

• implicit binding
• explicit binding
• arrow function lexical scope

Example questions:

• What would be the output? (Different ways of Prototype calls)
• What would be the output? [JavaScript Inheritance]

More this keyword based questions: https://devtools.tech/questions/all?categories=this-keyword

Polyfills

Discussion around polyfills and asked to implement some array methods. Full polyfills based questions set can be found here.

Other discussion topics can include IIFE and Execution context, Prototype Inhertiance, Method Chaining, and more.

Round 2: Machine Coding / React Implementation

This round evaluated practical React development skills, including state management, component architecture, and performance.

Common challenges included the following:

• File Explorer UI
• File Explorer UI 2
• Grid Lights Problem
• Breadcrumb Chain Problem

There were other questions around Custom React Hooks, Progress Bars, and more.

Round 3: Hiring Manager / Techno-Managerial Round

This round focused on advanced JavaScript understanding, architecture discussions, and past experience. We discussed topics like Event Loop, Blocking the main thread, JavaScript runtime, past projects, and more.

Round 4: Frontend System Design

A common design discussion included:

Design an E-commerce Filter Component

Topics discussed:

• filter state management
• performance optimization
• debouncing search queries
• URL-based filters
• reusable UI components
• Rendering performance
• minimizing re-renders
• React memoization
• lazy loading
• code splitting
• caching

Guide that helped me in frontend system design preparation

Round 5: HR / Culture Fit

The final round focused on cultural alignment and career goals.

Typical questions included:

• Why do you want to join CARS24?
• Why are you looking to switch roles?
• Describe a complex project you worked on.
• How do you collaborate with cross-functional teams?
• What are your salary expectations?
• Notice period and joining availability.

Key Takeaways

• Strong JavaScript fundamentals are critical
• Machine coding rounds are heavily React-focused. Practice a lot of different type of questions. Recommended resource: https://devtools.tech/questions/all
• Performance knowledge matters for senior roles
• Communication matters
• Focus on building system design thinking, not just learning jargons. Recommended guide: https://devtools.tech/frontend-system-design