1 unstable release

0.1.0 May 9, 2024

#2 in #deep-l


393 lines


Command line tool to localize Flutter apps using the DeepL translation API.


cargo install arb


Configure your Flutter l10n.yaml file to include a name-prefix and overrides-dir for human translations, for example:

arb-dir: i10n/translations
template-arb-file: app_en.arb
output-localization-file: app_localizations.dart
nullable-getter: false
untranslated-messages-file: untranslated.txt
overrides-dir: i10n/overrides
name-prefix: app


Convert all the strings from the template language into French and write the translations to app_fr.arb:

export DEEPL_API_KEY="<api key>"
arb translate --lang fr --apply l10n.yaml

To see what changes would be made omit the --apply option which will skip calls to the DeepL API and not write files to disc:

arb translate --lang fr l10n.yaml

After making changes to the template resource bundle run the update command to sync translations:

arb update l10n.yaml

For more commands and options run arb help.



Once a translation has been created the program will use a diff of the template keys to only translate when necessary and delete translations that have been removed. In order to detect changes to strings a cache file is kept in the application resource bundle directory named .cache.json.


If you have human improvements or corrections to the machine-generated translations you can use the --overrides option to prefer human provided translations.


To prevent placeholders from being translated they are converted to XML tags (<ph>) and the API requests are configured to ignore translations for those tags.


Set an API key to run the tests:

export DEEPL_API_KEY="<api key>"
cargo test


MIT or Apache-2.0 at your discretion.

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