Google domain specific round

Interview Experience
1

Google – Software Engineer (Frontend) – JavaScript & Browser Fundamentals Round

Education: B.Tech in Computer Science
YOE: 5+ (Frontend Developer at Razorpay)

Interview Focus:

Deep dive into JavaScript internals, browser architecture, and web performance optimization.

Topics Covered:

  1. JavaScript Core Concepts

Explained closures, event loop, and microtasks vs macrotasks.

Implemented debounce and throttle functions from scratch.

Discussed memoization and its role in performance optimization.

Difference between var, let, const and temporal dead zone.

  1. Browser Internals

How a browser parses HTML, constructs the DOM tree, and then the render tree.

Explained Critical Rendering Path and techniques to optimize load time (minification, code-splitting, lazy loading).

Discussed preloading, prefetching, and caching mechanisms.

Talked about event capturing & bubbling, and how to stop propagation efficiently.

  1. Networking & Caching

Explained how to manage browser cache, service workers, and cache invalidation.

Compared HTTP/1.1 vs HTTP/2 vs HTTP/3 (QUIC) and their impact on frontend performance.

Discussed CORS, same-origin policy, and security implications.

  1. Realtime & Communication

How to design a real-time chat UI using WebSockets.

Fallback mechanisms: SSE (Server-Sent Events) and long polling.