
DNS is just a phonebook until it isn't
76K views · May 18, 2026
How your browser turns a domain into an IP in 20 milliseconds, and the four caches that make it lie to you.
Related reading
NetworkingWhy localhost has two addresses
Type localhost and you usually hit 127.0.0.1. Sometimes you hit ::1 instead, your app works in one terminal and dies in another, and nobody tells you why. Here's the actual reason.
Jun 19, 2026 · 9 min read
System DesignHow Stripe actually works
Your card gets charged in under a second, across half a dozen systems, in a way that survives a server dying mid-payment. I traced one $20 charge from click to settlement.
Jun 14, 2026 · 14 min read
System DesignHow Discord serves millions of messages a second
One channel, a hundred thousand people typing at once. Discord stores it in a data model most tutorials tell you never to build. Here's why it holds up.
Jun 9, 2026 · 13 min read


