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Meta·Software Engineer·Technical Phone Screen·Senior

Senior
May 2026

Summary

Meta engineering manager interview with a classic system design flavored question about browser networking. Pretty standard stuff but there's more depth hiding in it than you'd expect.

Questions Asked (1)

Q1

Walk me through everything that happens, from the network layer up, when you type https://google.com into a browser and hit enter.

System DesignTechnical Trade-offs
Author's notes

I started with DNS and worked my way through TCP handshake, TLS negotiation, HTTP request, server response, rendering.

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AI HintsAI Generated

Suggested Approach

Start with a high-level overview of the entire process, then dive into each layer from DNS resolution to rendering, emphasizing trade-offs and optimizations. Use a structured narrative that connects networking, protocols, and browser internals, and relate it to system design principles like caching and load balancing.

Pro tip: Demonstrate depth by discussing not just the happy path but also failure modes, security considerations (e.g., TLS, HSTS), and performance optimizations (e.g., HTTP/2, CDNs). This shows you think about real-world reliability and scalability, which Meta values.

1. High-Level Overview

Briefly outline the main stages: DNS resolution, TCP/TLS handshake, HTTP request/response, and browser rendering. This sets the context and shows you understand the big picture.

2. DNS Resolution and Connection Setup

Explain how the browser resolves google.com to an IP address via DNS (caching, recursive resolvers), then establishes a TCP connection (3-way handshake) and TLS handshake for HTTPS.

3. HTTP Request and Response

Describe how the browser sends an HTTP GET request, including headers (cookies, user-agent), and how Google's servers process it, possibly involving load balancers, CDNs, and backend services, then return an HTTP response.

4. Browser Rendering and Resource Loading

Explain how the browser parses HTML, builds the DOM, fetches subresources (CSS, JS, images), and renders the page, mentioning critical rendering path and optimizations.

5. Trade-offs and Optimizations

Discuss key trade-offs and optimizations at each layer, such as DNS caching vs. TTL, TCP vs. QUIC, HTTP/1.1 vs. HTTP/2, and browser caching strategies.

Key Points to Mention

  • DNS resolution process: browser cache, OS cache, recursive resolver, root/TLD/authoritative servers, and DNS caching TTLs.
  • TCP 3-way handshake and TLS handshake (including SNI, certificate validation, and session resumption).
  • HTTP request/response cycle: methods, status codes, headers, cookies, and how CDNs and load balancers fit in.
  • Browser rendering pipeline: HTML parsing, DOM/CSSOM construction, render tree, layout, paint, and compositing.
  • Performance optimizations: HTTP/2 multiplexing, QUIC, caching (browser, CDN), compression, and critical rendering path.
  • Security considerations: HTTPS, HSTS, certificate pinning, and same-origin policy.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.