My Zscaler Frontend Interview Journey — From Rejection to Progress

Overview

This document details a candidate's two-time interview experience for frontend positions at Zscaler. The candidate applied for the Software Engineer — UI (React.js) role initially and was later contacted for a UI Developer role. The interview process consisted of three technical rounds, each designed to evaluate different aspects of frontend development expertise.

Interview Rounds

Round 1: Frontend Fundamentals

This round focused on core frontend knowledge, including React, JavaScript, and CSS. The interviewer assessed the candidate's understanding through conceptual questions and basic coding tasks. Specific areas covered included:

• React.js Questions:
  • React vs. Vue comparison, focusing on flexibility vs. simplicity.
  • Version of React used in projects.
  • API call methods (Axios vs. Fetch API) and their pros and cons.
  • Functional vs. Class Components, highlighting the benefits of functional components.
  • Lifecycle methods in class and functional components.
  • Explanation of useEffect, useState, and useRef hooks.
  • Difference between useMemo and useCallback.
  • Redux flow: Actions → Reducers → Store → UI updates.
  • Purpose of mapDispatchToProps.
  • How the Virtual DOM works.
• CSS Questions:
  • Different display properties in CSS.
  • Explanation of flex properties.
  • Difference between inline and block elements.
  • justify-content vs. align-items.
  • Different position properties in CSS.
  • Meaning of display: inline-block.
  • Explanation of the CSS Box Model.
• JavaScript Questions:
  • Writing a Promise in JavaScript.
  • Removing duplicates from an array.
  • Explanation of async/await.
  • How .indexOf() works.

Round 2: Implementation-Focused

This round was more challenging, emphasizing practical problem-solving skills. Candidates were required to apply their knowledge to solve real-world problems and demonstrate strong implementation abilities.