How I Set Up i18n in My React/Next.js App Without Losing My Mind

Last month I shipped a SaaS app in 6 languages. The translation part took me 2 days. Not 2 weeks. Two days. If you've ever set up internationalization in a production app, you know that sounds suspicious. The typical i18n story goes like this: you spend a day configuring the library, another day wiring up translation files, then you lose the next two weeks chasing down missing keys, syncing JSON files back and forth with translators, and praying that your build doesn't break because someone added a comma in the wrong place. I want to share what actually worked for me, and the specific decisions that saved me from the usual i18n death spiral. The problem nobody warns you about Every i18n tutorial starts the same way: install a library, create a locales/ folder, add some JSON files. Done! Except that's only 10% of the work. The other 90% is: Key management - Who decides the key names? What happens when you rename a component and forget to update the key? What about unused keys from featu