Blog

From BGP Anycast routing to tiered cache hierarchies and Surrogate-Key purge — how CDNs actually move traffic from your origin to the nearest edge server.

Here's a scenario I see in almost every codebase I review. A developer writes an async function that reads some state, does a bit of work, then writes back a result. In tests, it's fine. In development, it's fine.

Your Node.js server calls res.send("hello") and somewhere, 1400 bytes cross the planet in 80 milliseconds and appear correctly in a browser. That's wild. But what actually happens?

Stop using boolean props as imperative commands. In React 19 ref is just a prop — accept it, or use useImperativeHandle to expose a clean typed API for focus, reset and validate.

A client-side router watches the URL, matches it against patterns, and calls a handler. Build one in 110 lines — params, wildcards, back/forward — and see the four decisions every router makes for you.

overflow:hidden and CSS stacking contexts trap your modals and tooltips. React's createPortal escapes both while keeping the React tree — and context — intact.

One 'use client' at the top of your layout wipes out every performance benefit RSC offers. Learn how to push the boundary to leaf components and keep your server tree intact.

Stop adding props for every variation. Compound components let parent and children share state via Context — the pattern powering shadcn/ui, Radix UI, and every serious React UI kit.

When useState leaves you with six interdependent state variables, useReducer gives you one coherent state machine — plus a reducer you can test without mounting a component.