I build online stores and I run a few of my own, which means I have made most of the expensive mistakes personally. This is where I write down what the work actually involves: how a theme decides more than it looks like it does, what a checkout costs when it is clumsy, which platform suits which kind of catalog, how shipping prices and payment rails quietly set the margin. I care about numbers more than opinions, and I would rather show the wiring than describe the view. Everything here comes from stores with real stock and real postage, and I keep the notes blunt because that is the only kind worth reading twice.