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 via a terminal command. Basic variables (strings and integers) are supported, however neither genders nor plurals are planned to be supported. If you require such functionality, consider using arb_generator.

Note that as of version 2.0.0, null safe code is generated. Please use version 1.5.0 for non-null safe projects.

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.

keys fr en en_GB de
plainText Bonjour le monde! Hello world! Hello world! Hallo Welt!
welcome Bienvenu %name$s! Welcome %name$s! Welcome %name$s! Willkommen %name$s!
favoriteColor Quelle est votre couleur préférée? What is your favorite color? What is your favourite colour? Was ist deine Lieblingsfarbe?

Localizations can be specified for a region by appending the country code.

Add dependency

    sdk: flutter

Define Settings

Settings for flappy_translator must set in your project's pubspec.yaml file. input_file_path is the only required parameter.

  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
  generate_comments: false
  comment_languages: []
Setting Default Description
input_file_path N/A Required. A path to the input CSV/Excel file.
output_dir lib A directory to generate the output file.
file_name i18n A filename for the generated file.
class_name I18n A class name for the generated file.
delimiter , CSV files only: a delimited to separate columns in the input CSV file.
start_index 1 The column index where translations begin (i.e. column index of default language).
depend_on_context true Whether the generated localizations should depend on BuildContext
use_single_quotes false Whether the generated file should use single or double quotes for strings.
replace_no_break_spaces false Whether no break spaces (\u00A0) should be replaced with normal spaces (\u0020).
expose_get_string false The default value for whether a getString method should be exposed.
expose_loca_strings false The default value for whether a locaStrings getter should be exposed.
expose_locale_maps false The default value for whether a localeMaps getter should be exposed.
generate_comments false Whether documentation comments should be used to display translations.
comment_languages [] Languages that are displayed in the comments. Empty -> All languages are used.

Run package

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

flutter pub get
flutter pub run flappy_translator

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 {
  const MyApp({super.key});

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

Then use the generated I18n class!

class Home extends StatelessWidget {
  const Home({super.key});

  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('flappy_translator'),
      body: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            Text(I18n.of(context).welcome(name: 'Dash')),

Please see example for more information.

Material Localizations

Supporting a language (i.e. ga or cy) not included in GlobalMaterialLocalizations requires adding a material localization class and delegate. Although this is out of the scope of this package, a warning is logged to the console during code generation. More info.

Rules and functionalities


Locales are specified in the top row and are expected to be given in the form en or en_US.

Default language

The column at start_index is considered the default language. This means that:

  1. If this column does not have a value, the loca key instead will be used.
  2. If another language does not have translations for a given key, the value of the default language will be used.


Each loca key must begin with a lowercase letter, after which any combinations of lowercase, uppercase, digits or underscores are valid.


In order to include variables in loca strings, they need to be written in the format %<VAR NAME>$<VAR TYPE>. Presently only integers and strings are supported as variable types.

  • %myVariable$d (d stands for an int)
  • %myVariable$s (s stands for a String)

All variables are required. Consider the key welcome from example. The generated function signature is

String welcome({
  required String name,

Note that if the variable's name starts with a number, the generated variable name will be var<VAR NAME>. So, for instance, %1$d would become var1.