Domains, environments & the operating rhythm

The app is live; this lesson makes it yours and makes changing it safe:

• The domain: buy one (~$10-15/year — the best money-per-legitimacy ratio in software), add it in the platform dashboard, set the DNS records it tells you to (the assistant translates registrar-speak), and HTTPS certificates happen automatically. replyable-seven-chi.vercel.app is a project; yourname-replyable.com is a product.
• Preview deployments — the platform's best gift: every branch you push gets its own temporary URL running that version, with production untouched. The professional rhythm, sized for one person: work on a branch → push → check the preview URL (run the critical path there) → merge to main → production updates itself. (Branches are two new git verbs, and your first one takes five minutes: git checkout -b my-change creates and switches to a branch; push it and GitHub offers the merge button; git checkout main brings you home. Ask the assistant to walk your first round trip.) You will never again test a risky change on production, which puts your deployment hygiene ahead of a depressing share of the industry.
• Production hygiene for the AI feature: confirm the spending cap and rate limit survived the move (test the limit against the live URL — actually trip it; one heads-up: Module 6's simple in-memory counter resets whenever the platform spins up a fresh server instance, so if the live test won't trip reliably, that's why — ask the assistant to move the counter into your hosted database, the durable home it always deserved), check the provider dashboard's usage view after your first day live, and set the billing alert. A public URL with an AI route is a small standing invitation; you've made abuse bounded and observable, which is the whole game at this scale.
• The operating rhythm — ten minutes a week: platform logs skimmed for errors you didn't know about, AI spend glanced at, one run of the critical path, dependencies updated monthly (npm update, then the full test script — updates are changes too). Small, boring, and the difference between an app that's up and an app that's maintained. Put it in your calendar; every operations course in this academy ends with the same sentence because it's the sentence that's true.