scroll to fall
Descent
Every page you load falls through five layers before anything appears on screen. Most people never see any of them. Scroll, and you fall through all five.
opening the shaft…
01 · client
It starts in a browser
Someone types your domain and presses enter. Everything below this line is invisible to them, and all of it has to work for the page to appear. This is the only layer most people ever see.
GET / · TLS 1.3 · HTTP/2
02 · edge
The nearest edge answers
The request lands at whichever point of presence is closest — not at a server you own. Cached responses stop here and never travel further, which is why the fastest request is the one that never reaches your origin.
cache HIT · fra1 · 12ms
03 · balancer
Traffic is split across what's healthy
A miss goes deeper. The balancer knows which instances are alive because it keeps asking them, and it routes around the ones that stopped answering. Deploys are safe here precisely because this layer is willing to ignore a machine.
3 healthy · 0 draining
04 · compute
Something has to actually run
A container starts, or a warm one is reused. Your code executes here — the React tree renders, the queries fire, the response is assembled. This is the layer everyone means when they say "the app".
warm · 41 req · 68ms p95
05 · store
And at the bottom, the truth
The datastore is the one layer you cannot rebuild from a git push. Everything above it is replaceable in minutes. That asymmetry is the single most important fact in operating a system, and it decides where the care goes.
primary · 2ms · replicated
back at the surface
I work at every floor
Five years building the top of that shaft, five years running the bottom of it. Most engineers pick one end.