@json-translate/check

Validate translated JSON locale files before they break your app.

@json-translate/check is a small dependency-free CLI for i18n and localization workflows. It compares translated JSON files against a source locale and fails when structure or placeholders drift.

Usage

npx @json-translate/check --source locales/en.json --target locales/fr.json --target locales/de.json

You can also pass comma-separated targets:

npx @json-translate/check -s locales/en.json -t locales/fr.json,locales/de.json

Checks

• Target JSON parses successfully
• Source keys are not missing from target files
• Unexpected extra keys are reported
• Placeholders are preserved across source and target strings

Placeholder patterns checked:

• {name}
• {{count}}
• ${value}
• %s, %d, %i, %f

Example Output

FAIL locales/fr.json
  missing key: nav.save
  extra key: legacy.banner
  placeholder missing at greeting: {name}

GitHub Actions

name: Locale checks

on:
  pull_request:

jobs:
  json-locales:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Validate translated JSON locale files
        run: npx @json-translate/check --source locales/en.json --target locales/fr.json,locales/de.json

Exit Codes

• 0: no validation issues
• 1: validation issues found
• 2: usage error or JSON read/parse error

Where It Fits

Use JSON Translate to create draft translations, then run this CLI before merging translated locale files.

• Translate JSON files online: https://www.json-translate.com/?utm_source=cli&utm_medium=devtool&utm_campaign=json_translate_check
• CLI guide: https://www.json-translate.com/json-translate-check
• i18next workflow: https://www.json-translate.com/translate-i18next-json

Common Use Cases

• i18next locale files
• next-intl JSON files
• React Intl message catalogs
• FormatJS JSON catalogs
• Vue I18n locale files
• Chrome extension _locales/*/messages.json files