i18n Checker
Compare locale JSON files: missing, extra and empty keys, untranslated text, placeholders that don't match, strings that may overflow.
About this tool
Paste or open a base locale and one or more translated locale files in JSON to find missing, extra and empty keys, text that was left untranslated, placeholders that do not match and strings that are much longer than the original.
Placeholders in the {name}, {{name}} and %s styles are compared, including ICU plural and select messages. The files are read in a background worker on this page and never uploaded. At most 3 MB in total is read, and the first 500 issues are listed.