flutter locale gen

Dart tool that will convert your default locale json to dart code.

pub package Build Status Analyzer Build Status Formatting Build Status Test Coverage Status MIT license




Add dependency to pubspec

pub package

  sprintf: ^6.0.2
  locale_gen: <latest-version>

Add config to pubspec

Add your locale folder to the assets to make use all your translations are loaded.

    - assets/locale/

Add the local_gen config to generate your dart code from json files

  default_language: 'nl'
  languages: ['en', 'nl']
  locale_assets_path: 'assets/locale/' #This is the location where your json files should be saved.
  assets_path: 'assets/locale/' #This is the location where your json files are located in your flutter app.
  output_path: 'lib/util/locale/' #This is the location where your localization files will be created in your flutter app.
  doc_languages: ['en'] #Only generate docs for the given languages. Defaults to all languages. An empty list will skip doc generation

Run package with Flutter

flutter packages pub run locale_gen

Run package with Dart

pub run locale_gen

Migration steps <9.0.0 to >=9.0.0

With version 9.0.0 of local gen you no longer have static access to the translations, instead you can now manually manage the different localization instances. You can for example store a localization instance as a static. This way you can use it largely the same way as before. Example from the example project:

class LocaleViewModel with ChangeNotifier {
  static final Localization localizationInstance = Localization();

  Future<void> init(){
    await Localization.load(
      locale: locale,
      localizationOverrides: customLocalizationOverrides,

You can then access this localizationInstance anywhere in the project like:


Custom asset bundle

Since version 10.0.0 you can specify the bundle to load the assets from in the load function. This can be used as an alternative to overriding translations, fetching them from the network, ...

Migration steps <7.0.0 to >=7.0.0

With the newest version of locale_gen the context no longer needs to be provided when accessing the translations. This means there are a couple of breaking changes.

The first one is that you can now directly get the translation from the Localization object without having to pass the context, so instead of:


you can now do


The second breaking change is how you initialize/change the locale. Before you could do this by changing the localizationDelegate that is passed to the materialApp, but now you just call the load function of the Localization object. So instead of:

      localeDelegate = LocalizationDelegate(
        newLocale: locale,
        localizationOverrides: customLocalizationOverrides,

you now do:

await Localization.load(
      locale: locale,
      localizationOverrides: customLocalizationOverrides,


Arguments are supported as of 0.1.0

You can pass a String, an integer or a double to as an argument. (int and double since 8.0.0, num before that)

Since 8.0.0 you can use more specifications from C's sprintf to apply format to numbers. If any modifier is causing a mismatch, please create a ticket

Formatting for String: %1$s Formatting for int: %1$d Formatting for double: %1$f

The number in between % and $ indicate the index of the argument. It is possible to place an argument in 1 language first but in another second:

ex (Grammatically incorrect but it makes my point):

nl '%1$s, ik woon in %2$s. Wist je dat niet?' => KOEN, ik woon in ANTWERPEN. Wist je dat niet?

fr 'I live in %2$s. You didn't knew that %1$s?" => I live in ANTWERP. You didn't knew that KOEN?

Note: As of 6.0.0 non-positional arguments are also supported. You cannot use both positional and non-positional arguments in the same string. Example:

'%s, ik woon in %s. Wist je dat niet?' => KOEN, ik woon in ANTWERPEN. Wist je dat niet?


Since 8.0.0 plurals are supported. To specify a plural, you can use the following syntax in the json file:

  "example_plural": {
    "zero": "You have no items",
    "one": "You have %1$d item",
    "two": "You have 2 items, party!",
    "few": "You have a few items, nice!",
    "many": "You have many items, fantastic!",
    "other": "You have %1$d items"

This will generate functions where you pass the number of items as an argument. The function will then return the correct translation based on the number of items. The count argument WILL NOT be passed as an argument for string interpolation.

Note that the "other" key is always required, the other keys are dependant on the language in question

Working on mac?

add this to you .bash_profile

 flutter packages get && flutter packages pub run locale_gen

now you can use the locale_gen with a single command.



This repo contains an example how to use this package.

Packages used:

  • flutter_localizations
  • shared_preferences
  • provider
  • kiwi

Other packges based on locale_gen

  • icapps_translations