03 / ENGINEERING LAB

Engineering Lab

A collection of interactive experiments exploring how systems work underneath the abstractions.

Read less. Understand by interaction · run, step and break things to see them move

  1. Event Loopcall stack / microtasks / timersWhy the output of that async snippet is A, D, C, B — not A, B, C, D.
  2. HTTP Lifecycledns / tcp / tls / application / databaseWhat actually happens between hitting Enter and seeing 200 OK.
  3. Database Indexsequential scan / index lookupWhy finding a row by email can be one lookup instead of a full scan.

Every experiment is a small, honest simulation: the order of events and the numbers you see are computed by the simulation itself, not invented for the animation.