What it is
A checker for app translation files. It reads JSON, YAML, .properties, Apple .strings, gettext .po or a plain list of keys and compares every language with the source.
Translation checks for apps in many languages
Every string gets its visa before it crosses the border.
Locale Gaps compares your source language file with each translation and stops what would break on screen: missing keys, empty or untranslated text, lost placeholders, broken markup and plural forms a language needs but the file does not have. Then it hands translators a file with exactly what is left to do.
Entry stampsP<LOCALE<GAPS
Who it is for
Frontend and mobile developers, product managers shipping in several languages, localization managers and translators who want a clean list instead of a screenshot of a raw key.
What it solves
A missing key shows users text like cart.checkout, a lost placeholder prints {{amount}} instead of a price, and a missing plural form makes Russian or Arabic read wrong. You see all of it before release.
Check your translation files
Paste the source file, add one box per language and press Check translations. Nothing leaves this page.
Options
Long translations often overflow buttons and menus. 1.6 means 60 percent longer.
Comma separated, for example brand or product names. Numbers, codes and single brand words are already ignored.
Nothing checked yet
Paste a source file and at least one translation, or load the sample app to see a full report.
What it checks
Each rule exists because it has broken a real screen somewhere. None of them needs a model or a guess.
Missing and empty keys
Every source key must exist in the translation and have text. Otherwise users see cart.checkout or an empty button.
Untranslated text
Text identical to the source is flagged unless it is a number, a code, a link or a word you allowed, like your brand name.
Placeholders
Variables like {{name}}, {name}, %s, %1$d, %{name} and :name must match the source exactly. A renamed variable prints nothing.
Plural forms
Plural rules come from your browser, the same rules apps use. Russian needs one, few and many. Arabic needs six forms. Both ICU messages and i18next suffixes like items_few are checked.
Markup
Tags like <a>, <b> or <0> must survive translation, or links and emphasis disappear.
Length, extras and duplicates
Very long translations, keys that exist only in the translation and keys defined twice are listed with lower priority.
How to use it
Paste the source file
Usually English. Open the file or paste its content. Nested keys are flattened to paths like checkout.pay.
Add each language
Type the language code and paste its file. Each language can use its own format.
Press Check translations
Each language gets a stamp with keys present and strings ready to ship, plus a count per issue type.
Fix or hand off
Filter the findings, then download the file to translate for each language or the full CSV.
Keep the note
Copy the release note into your pull request or release checklist. The hash shows the report was not edited.
What it does not do
- It does not judge translation quality or tone. A wrong but complete sentence passes.
- It does not translate anything and does not send text to any service.
- YAML support covers the usual locale file shape: nested keys and single line values.
- Gender and select rules in ICU messages are not checked yet, only plurals.
Questions
Are my files uploaded anywhere?
No. Parsing and checks run in this page. Close the tab and the text is gone.
Why does German show Untranslated for a word that is the same in both languages?
Some words really are the same. Add them to Words that may stay the same and run the check again.
Where do the plural rules come from?
From Intl.PluralRules in your browser, which follows the Unicode CLDR data that most apps use.
Can I check only keys, without text?
Yes. Paste plain lists of keys. Missing and extra keys are reported, the text checks are skipped.