A tool which automatically generates Flutter localization resources from CSV and Excel files.

This is especially useful as any team member can edit the CSV/Excel file, with the subsequent translations imported into the project with the use of a simple terminal command. This contrasts starkly to the default i18n approach in which dart files need to be manually for new keys and languages. More information can be found in Internationalizing Flutter apps.

Getting Started

In order to use the flappy_translator package, please provide your translations in a CSV or Excel file. For CSV files, delimiters , and ; have been tested to work.

The following table is used in the example project:

appTitleMa super applicationMy awesome applicationMi gran applicationMeine tolle App
subtitleUn sous titreA subtitleUn subtitulòEin Untertitel
descriptionUn texte avec une variable : %1$sText with a variable: %1$sUn texto con una variable : %1$sText mit einer Variable: %1$s
littleTest"Voici, pour l'exemple, ""un test"" avec la variable %age$d""Here is, for the example, ""a test"" with the variable %age$d""Aqui esta, por ejemplo, ""una prueba"" con la variable %age$d""Hier ist, zum Beispiel, ""ein Test"" mit der Variable %age$d"

Add dependency

    sdk: flutter

Note that flappy_translator requires dart sdk >= 2.7.

Define Settings

Settings for flappy_translator can be optionally set in your project's pubspec.yaml file:

  input_file_path: "test.csv"
  output_dir: "lib"
  file_name: "i18n"
  class_name: "I18n"
  delimiter: ","
  start_index: 1
  depend_on_context: true
  use_single_quotes: false
  replace_no_break_spaces: false
  expose_get_string: false
  expose_loca_strings: false
  expose_locale_maps: false
input_file_pathN/AA path to the input CSV/Excel file.
output_dirlibA directory to generate the output file.
file_namei18nA filename for the generated file.
class_nameI18nA class name for the generated file.
delimiter,CSV files only: a delimited to separate columns in the input CSV file.
start_index1The column index where translations begin (i.e. column index of main language.)
depend_on_contexttrueWhether the generated localizations should depend on BuildContext
use_single_quotesfalseWhether the generated file should use single or double quotes for strings.
replace_no_break_spacesfalseWhether no break spaces (\u00A0) should be replaced with normal spaces (\u0020).
expose_get_stringfalseThe default value for whether a getString method should be exposed.
expose_loca_stringsfalseThe default value for whether a locaStrings getter should be exposed.
expose_locale_mapsfalseThe default value for whether a localeMaps getter should be exposed.

Run package

Make sure that your current working directory is the project root.

An input file path must be supplied, either as a setting in pubspec.yaml or as a command line argument (CLA), while the output directory can also be optionally supplied as a CLA.

flutter pub get
flutter pub run flappy_translator <test.csv> <output dir>

Update iOS Info.plist

For iOS, ios/Runner/Info.plist needs to be updated with an array of the languages that the app will supports:


For more information, see Internationalizing Flutter apps.

Use the i18n generated file

The package used your input file in order to generate a file named file_name in output_dir you provided. The following example uses the default class_name I18n with a dependency on BuildContext.

Firstly, add the I18nDelegate to your delegates:

class MyApp extends StatelessWidget {
  Widget build(BuildContext context) {
    return MaterialApp(
      localizationsDelegates: [
        const I18nDelegate(),
      supportedLocales: I18nDelegate.supportedLocals,
      home: Home(),

Then use the generated I18n class!

class Home extends StatelessWidget {
  Widget build(BuildContext context) {
    return Scaffold(
      body: SafeArea(
        child: Center(
          child: Column(
            children: <Widget>[
              Text(I18n.of(context).description(var1: 2)),
              Text(I18n.of(context).littleTest(age: 32)),

Please see example for more information.

Rules and functionalities

Default language

The first language's column of your CSV file will be considered as the default one. That means :

  • If other languages does not have translation for specific words, it will take the corresponding one in the default language.

  • The first column must be totally filled ! It will not work otherwise.

Handling different languages for one country

You have the possibility, since version 1.4 to write something like de_CH. It will take the Swiss's German language.

Add variables in Strings

We added the possibility to handle variables in the Strings. This means respecting some rules :

  1. In order to be able to recognize them, you must write them this way :
  • %myVariable$d (d stands for an int type)
  • %myVariable$s (s stands for a String type)
  1. if your variable's name start with a number, the generated name will be varmyVariable Otherwise, the generated variable name would be the name you provided.
  • %1$d becomes var1
  • %age$d becomes age
  1. Variables are required in the generated dart code

Let's take the example of the description String in the CSV we used.

The generated function signature will be :

String description({
  @required String var1,