Existing translations

You don't have to start from an empty project. If you already have translated files, the CLI works alongside them: it fills in what's missing and leaves your existing translations in place.

Point the config at what you have#

Set your source and target locales and the file patterns, matching wherever your translations already live:

{
  "sourceLocale": "en",
  "targetLocales": ["de", "fr"],
  "files": [{ "pattern": "locales/en.json" }]
}

If locales/de.json and locales/fr.json already exist, they stay as they are.

Fill the gaps#

lingo push --backfill-missing

--backfill-missing only produces targets that are missing — a locale with no file yet, or (after the first run) keys the engine hasn't translated. Files you already have aren't overwritten.

✓ Run lfr_a8c...: localized 1 target file(s), 2 already up-to-date.

Keep specific values frozen#

If some existing translations are hand-reviewed and must never change, mark them preservedKeys so no future run touches them:

{ "pattern": "locales/en.json", "preservedKeys": ["legal.terms"] }

How the lockfile bootstraps#

The first push records a hash of every source file in .lingo/lock.json. From then on, plain lingo push only sends sources that changed — your existing translations are never re-sent unless you change the source or force it. Commit the lockfile alongside your translations. See Configuration.