WISHCAST
Free tool

Localization check

Add your string files to find missing keys, broken placeholders like {0} or %s, text likely to overflow, untranslated lines and encoding damage. Reads JSON, CSV or TSV (including Unity Localization exports), .po, .strings and Android XML.

Files are read in your browser and never uploaded. Add a “Max Length” column to a CSV to check hard limits instead of the length ratio.