Interface, server logic, database and the hosting it runs on. You describe what it needs to do; I hand back something working at an address you can open, not a prototype that only runs on my laptop.

Plenty of teams have something that works locally and nobody who wants to own the server. I set that part up: the machine, the domain, certificates that renew themselves, applications kept separate so one failure cannot spread, and alerts when something stops responding.

Fixing, maintaining and extending an existing system, including one with no documentation and no original author available. I am used to reading unfamiliar code and finding out what holds it up before changing it.

Between hosting providers, or from a managed service onto your own infrastructure, with the data intact and the old addresses still working afterwards. Every project on this site has been moved this way, database included.