Command line

A Python package with no dependencies. Without a key it runs as the free demo: 10,000 characters per file, up to 8 languages per run.

Run

pip install kaeris
kaeris translate en.json --langs de,ja

Output, shortened

→ no key: free demo limits 10,000 chars per file, 8 languages per run, get a key: kaeris.dev/developer
→ Translating en.json → de, ja
✓ Wrote 2 file(s) to /home/you/app
/home/you/app/de.json
/home/you/app/ja.json
✓ Translation QA: no placeholder loss, no overflow risks

Next commands

Command	What it does
`kaeris init`	Writes `kaeris.json` with your source file, languages and output folder, so `kaeris translate` runs with no flags. `--preset` fills it for i18next, react-i18next, next-intl, react-intl, vue-i18n or flutter-arb.
`kaeris translate --only-new`	Translates only new and edited keys. `kaeris.lock` next to the source remembers what is done. JSON and ARB.
`kaeris check`	Finds broken translations on your machine, no key. Without Python: `npx kaeris check` (Node 18+). Details of the check.
`kaeris languages`	Prints the 46 language codes.
`kaeris quota`	How much of this month's volume is left on your key.

Flags you will use

Flag	Meaning
`--langs de,ja`	Target languages, comma-separated. Short form `-l`.
`--out locales`	Where to write the files. Default: next to the source.
`--verify`	Translates every result back to English and writes `verify.json`, so you can check the meaning.
`--keep 'KAERIS,GitHub'`	Words that stay as written in every language, such as brand names.
`--context 'a bank app'`	One line about your app. Helps with words that have two meanings.
`--tone formal`	`neutral`, `formal` or `casual`.
`--model openai/gpt-4.1`	Lifetime: the OpenRouter model to translate with. One per language: `models` in `kaeris.json`. On other plans the request is refused with the reason.
`--key`	Your API key. Or set `KAERIS_API_KEY`, which is safer: a key typed after `--key` stays in your shell history and shows in the process list.
`--source-lang en`	Language of the source file. Default `en`; also finds `locales/<lang>/<namespace>.json` layouts.
`--back-lang en`	Language `--verify` translates back into. Default `en`.
`--lock PATH`	Where `kaeris.lock` lives. Default: next to the source.
`--assume-current`	First `--only-new` run on a project that is already translated: trust the existing translations instead of translating everything again.
`--tm PATH`	Translation memory file, `kaeris-tm.json` next to the source by default. It reuses translations by text, so a renamed key or a fresh clone does not pay twice. `--no-tm` turns it off.
`--receipt run.json`	Writes a record of the run: model, plan, languages delivered, characters charged and reused. Counts only, no strings.

Files: .json .yml .yaml .strings .xcstrings .po .arb .xml .csv .xliff .xlf .properties .resx .ftl .md .mdx. An unknown language code is refused before anything is sent: kaeris languages lists the valid ones. Exit codes of translate: 0 done, 1 error, 3 some languages came back untranslated. Full list: kaeris translate --help.

Guides by format: JSON · YAML · PO · XLIFF · ARB · .strings · .xcstrings · Fluent · .properties · .resx · CSV · Markdown · Android XML

CI recipes (in English): GitHub Actions · GitLab CI · pre-commit · Make and npm scripts