Internationalization (or "I18N") features are those being in relation to program's ability to support localized messages (see locale), currencies, and other region-specific settings.

Interchange has a rich set of I18N features that allow conditional message display, differing price formats, different currency definitions, price factoring, sorting, and other settings. Currently, those features are implemented as Interchange-specific, and do not rely on Perl's I18N/L10N features, except for the built-in POSIX support (use locale and setlocale()).

The definitions are maintained in the catalog.cfg file, through the use of Interchange's Locale directive. All settings are independent for each catalog and each user visiting that catalog; in other words, customers can access the same catalog in an unlimited number of languages, currencies and regional settings.

See locale glossary entry for more specific information.