Networking
What actually happens between your fetch call and someone else's server, and where it goes wrong.
8 topics
What happens when you type a URL
The end-to-end walkthrough that every layer of the stack hangs off, told once so the rest of networking has somewhere to attach.
core30 minDNS and name resolution
A distributed, aggressively cached lookup from names to addresses — and the reason "it's DNS" is a recurring incident postmortem punchline.
core20 minTCP, UDP, and QUIC
Reliable ordered bytes, unreliable datagrams, and the newer transport that keeps reliability without inheriting TCP's head-of-line blocking.
core25 minTLS and certificates
How two strangers agree on a shared secret over a hostile network, and what a certificate actually proves.
core25 minHTTP semantics and status codes
Methods, status codes, and headers as a contract — safe, idempotent, and cacheable are properties you promise, not descriptions of your handler.
core25 minLatency, bandwidth, and the speed of light
Bandwidth keeps improving and round-trip time does not, which is why most web performance work is about removing round trips rather than bytes.
core20 minProxies, CDNs, and the network edge
Everything sitting between the browser and your origin — and why "the server" in a request is usually four servers.
deep20 minNetwork failure modes
The network is not reliable, and the hardest failure is not an error — it is a request that neither succeeds nor returns.
core25 min