i1n

Translating your app is never the hard part. The hard part is everything around it: five JSON files that drift out of sync, a {name} variable that some translator turned into {nombre} and broke interpolation, a typo'd key that renders blank in production, and the three strings you forgot to translate into Japanese that nobody notices for weeks because nobody on your team reads Japanese. i1n is localization as code. Your strings live in plain JSON locale files, in your repo, where they belong. One command (i1n push --translate) sends new or changed keys for AI translation into any of 182 languages, with your product's context so "Save" comes back as the verb, not the noun. Pull them back and you get typed TypeScript definitions: typo a key and the compiler catches it before your users do. The part most tools skip: i1n check runs in CI and fails the build when a language falls out of parity with your source, a placeholder gets mangled, or a value ships empty. Translation bugs become build errors instead of user reports written in languages you can't read. It also runs as an MCP server (listed in the official MCP Registry), so if you work with Claude Code, Cursor or Windsurf you can literally tell your agent "internationalize this component" and it extracts the strings, translates them, and rewrites the code with typed calls. i1n runs in production at belo, a LATAM fintech, where the dashboard ships in 10 languages. The CLI is open source (MIT). Setup is npx i1n init and about two minutes to your first translated locale. The free tier has no card and no trial countdown; paid plans start at $29/month when you outgrow it. If you've ever copy-pasted keys between locale files at 11pm, this was built for you, by someone who was doing exactly that.