All videos
1:08
ReelNetworkingIntermediate
Why localhost has two addresses
98K views · Jun 17, 2026
127.0.0.1 and ::1 are not the same thing, and the day you learn that is usually the day your app breaks in one terminal but not the other.
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
NetworkingHow DNS finds a website in 20ms
Four servers you've never heard of answer a question you ask thousands of times a day. And four caches in between will happily give you yesterday's answer.
Apr 29, 2026 · 9 min read
