translint

Install

pip install git+https://github.com/munzzyy/translint

Or skip installing it, since it's one file with no dependencies:

curl -LO https://raw.githubusercontent.com/munzzyy/translint/main/translint.py
python translint.py --help

Usage

translint locales/                          # scan a directory, base=en
translint locales/ --base fr                # use fr.json as the reference instead
translint locales/en.json locales/de.json   # check specific files
translint locales/ --json                   # machine-readable report
translint locales/ --strict                 # also fail on extra keys + untranslated
translint locales/ --allow-identical brand.name   # suppress one heuristic false positive

--base defaults to en - the locale name (filename stem) every other discovered file gets checked against. Exit code is 0 when everything's clean, 1 when translint found something to fix, 2 if a path couldn't be read or parsed at all - a bad-JSON error and a real lint finding never look the same to a script.

See it catch something

This is real output, not a mockup. examples/locales/ in the repo ships one base file (en.json) and two translations (fr.json, de.json) with a handful of real, intentionally planted problems. Below is translint run against them, copied verbatim - red categories fail the run by default, amber ones are reported but only fail under --strict.

de (examples\locales\de.json):
  empty values (1):
    - checkout.success
  possibly untranslated (1, heuristic):
    - brand.name

fr (examples\locales\fr.json):
  missing keys (1):
    - nav.settings
  extra keys (1):
    - checkout.oldStep
  placeholder mismatches (1):
    - checkout.confirm: base has ['{amount}', '{last4}'], locale has ['{last4}', '{total}']
  possibly untranslated (2, heuristic):
    - brand.name
    - errors.networkDown

1

translint exits 1 whenever there's something to fix. Exit 0 means every locale is clean; exit 2 means a path couldn't even be read or parsed. Try it yourself against these same files: translint examples/locales --base en.

What it checks

• Missing keys

  A key that exists in the base locale but never made it into a translation.

• Placeholder mismatches

  {amount} became {total} - the bug that renders fine in every test that doesn't pass real interpolation data, and throws the moment one does.

• Empty values

  A key that exists but was never filled in.

• Extra keys

  Left over from a rename. Reported, but doesn't fail the run unless you pass --strict.

• Possibly untranslated

  A heuristic: the value still reads byte-identical to the base after stripping placeholders, punctuation, and numbers. Allowlist real matches with --allow-identical or --do-not-translate.

• Three file formats

  JSON (nested or flat dot-namespaced keys), gettext .po/.pot, and Java .properties, auto-detected by extension.

• Five placeholder styles

  {name}, {{name}}, %s/%d/%1$s, %(name)s, and ${name}/$name, diffed as a multiset so a doubled placeholder doesn't slip through.

• Scriptable output

  --json prints machine-readable results. Exit codes are just as script-friendly: 0 clean, 1 findings, 2 couldn't read or parse.

• Runs three ways

  CLI by hand or in a pre-commit hook, a GitHub Action that gates CI, or a Claude Code / Agent Skills skill, so a coding agent checks its own i18n changes before handing back a PR.

What it doesn't do

• No YAML locale files. Parsing YAML safely needs a dependency, and translint is stdlib-only on purpose.
• The untranslated-value check is a heuristic, not a hard rule. It flags what looks untranslated; it doesn't prove anything.
• It doesn't translate anything, and it doesn't validate translation quality - just structure: keys, placeholders, non-empty-ness.
• Non-recursive directory scan. Point it at a directory and it checks the files directly inside, not subdirectories.