Cities are runtimes that refuse to restart, and that's the most interesting thing about them

Hot-reloading is the wrong metaphor for cities and we should stop reaching for it. A city has no maintenance window. Every change is a live migration with people inside the data.

I want to write more about what it actually means to deploy to an environment you cannot turn off — and why I think most of the best ideas in software design are quietly stolen from people who design buildings, streets, and bus routes.