Deep Dive — What Happens When You Access a URL

Requirements

This is an open-ended conversation: from the moment you enter a URL (like www.example.com) into a browser, walk through the entire process. Be prepared for deep dives on:

• DNS resolution and its inner workings.
• CDN and edge caching behavior.
• Service discovery — how services locate each other.
• Authentication.
• Inter-service communication protocols.

Notes

• This round is truly open and unscripted — the questions may seem arbitrary, and the interviewer will probe deeper into whatever topics you bring up. Candidates who started with a wide scope often got cornered into specifics they couldn't handle.
• The best approach is to intentionally steer the discussion toward the subsystems you're most confident in and explore them thoroughly, rather than attempting to cover the entire stack superficially.

Preparation

• Construct a single, well-reasoned story that traces the request lifecycle (DNS → TLS → routing/CDN → load balancing → service → database), and decide in advance which two or three areas you'll guide the conversation toward.
• Practice the most frequently examined topics — DNS resolution steps, CDN caching behavior, service discovery, and authentication token flow — until you can handle a series of follow-up questions with confidence.