What Actually Happens When You Open A Website

You click a link. A page appears 200ms later. Here's every layer that has to work in that window — and which one to check first when it feels slow. In this video: The cache and service worker checks that can skip the network entirely DNS resolution, layer by layer Why TCP's handshake costs a full round trip before your request even starts TLS 1.3, certificate validation, and Time To First Byte as a diagnostic tool The render pipeline, and what changes in a modern single-page app 🔗 Download the FREE Big Tech System Design Playbook: https://www.albertopastormr.com/playbook 🎯 Want 1:1 help with your career or interview prep? Check out the coaching program: https://www.albertopastormr.com/coaching 📬 Subscribe to the Substack newsletter for written deep-dives: https://albertopastormr.substack.com/ Chapters: 0:00 – Intro 0:32 – Cache and service worker shortcuts 1:32 – DNS resolution 2:27 – TCP's handshake cost 3:48 – TLS and certificate validation 4:57 – Time To First Byte 5:47 – Rendering and the SPA twist 7:13 – Outro #distributedsystems #systemdesign #softwareengineering