# How to Set Up Flutter Localization with flutter_localizations and intl > Easily set up Flutter localization using flutter_localizations and intl. Learn to configure pubspec.yaml, l10n.yaml, and integrate AppLocalizations for global app reach. - Repository: [Flutter/skills](https://github.com/flutter/skills) - Tags: how-to-guide - Published: 2026-05-09 --- **To set up Flutter localization, add the `flutter_localizations` and `intl` packages to your project, enable code generation in [`pubspec.yaml`](https://github.com/flutter/skills/blob/main/pubspec.yaml), configure the [`l10n.yaml`](https://github.com/flutter/skills/blob/main/l10n.yaml) build file, and import the generated `AppLocalizations` class into your app's localization delegates.** Flutter's internationalization (i18n) workflow relies on two core packages: **`flutter_localizations`**, which provides the SDK's localization delegates and generation infrastructure, and **`intl`**, which handles locale-aware formatting and pluralization logic. According to the official `flutter/skills` repository, specifically the skill file at [`skills/flutter-setup-localization/SKILL.md`](https://github.com/flutter/skills/blob/main/skills/flutter-setup-localization/SKILL.md), this setup creates a type-safe `AppLocalizations` class that stays synchronized with your ARB translation files automatically. ## Configure Dependencies and Code Generation The first phase involves declaring dependencies and instructing the Flutter tool to generate localization code automatically. ### Add Required Packages You need both the Flutter SDK localization package and the Dart intl library. Run the following commands or update your [`pubspec.yaml`](https://github.com/flutter/skills/blob/main/pubspec.yaml) directly: ```bash flutter pub add flutter_localizations --sdk=flutter flutter pub add intl:any ``` Your [`pubspec.yaml`](https://github.com/flutter/skills/blob/main/pubspec.yaml) should include these entries: ```yaml dependencies: flutter: sdk: flutter flutter_localizations: sdk: flutter intl: any ``` ### Enable Flutter Generation To activate the automatic code generation that converts ARB files into Dart classes, add the `generate` flag under the `flutter` section in [`pubspec.yaml`](https://github.com/flutter/skills/blob/main/pubspec.yaml): ```yaml flutter: generate: true ``` This setting ensures the localization builder runs automatically after each `flutter pub get` or any Flutter command. ## Set Up the Localization Toolkit Once dependencies are configured, you must define where translation files live and how they should be processed. ### Create the l10n.yaml Configuration Create a file named [`l10n.yaml`](https://github.com/flutter/skills/blob/main/l10n.yaml) in your project root to configure the code generator: ```yaml arb-dir: lib/l10n template-arb-file: app_en.arb output-localization-file: app_localizations.dart synthetic-package: true ``` This configuration tells the builder to: - Look for ARB files in `lib/l10n/` - Use `app_en.arb` as the template for type generation - Output the generated class to the synthetic package `flutter_gen/gen_l10n/app_localizations.dart` ### Define ARB Resource Files Create the directory `lib/l10n/` and add your Application Resource Bundle (ARB) files. Start with the template file `app_en.arb` containing default strings and metadata: ```json { "helloWorld": "Hello World!", "@helloWorld": { "description": "The conventional newborn programmer greeting" } } ``` Add translation files for additional locales, such as `app_es.arb` for Spanish: ```json { "helloWorld": "¡Hola Mundo!" } ``` ## Generate and Integrate AppLocalizations With configuration in place, generate the Dart code and wire it into your application widget tree. ### Trigger Code Generation Run the following command to generate the localization class: ```bash flutter pub get ``` Because `flutter.generate: true` is enabled in [`pubspec.yaml`](https://github.com/flutter/skills/blob/main/pubspec.yaml), the tool automatically produces `app_localizations.dart` in the synthetic package. You do not need to manually edit generated files. ### Wire Delegates into MaterialApp Import the generated localizations and required delegates in your `lib/main.dart` or entry point file: ```dart import 'package:flutter/material.dart'; import 'package:flutter_localizations/flutter_localizations.dart'; import 'package:flutter_gen/gen_l10n/app_localizations.dart'; ``` Add the `AppLocalizations.delegate` along with the global delegates to your `MaterialApp` or `CupertinoApp`: ```dart MaterialApp( localizationsDelegates: const [ AppLocalizations.delegate, GlobalMaterialLocalizations.delegate, GlobalWidgetsLocalizations.delegate, GlobalCupertinoLocalizations.delegate, ], supportedLocales: const [ Locale('en'), Locale('es'), ], home: const MyHomePage(), ) ``` Access localized strings using `AppLocalizations.of(context)`: ```dart class MyHomePage extends StatelessWidget { const MyHomePage({super.key}); @override Widget build(BuildContext context) { final l10n = AppLocalizations.of(context)!; return Scaffold( appBar: AppBar(title: Text(l10n.helloWorld)), body: const Center(child: Text('…')), ); } } ``` ## Handle Advanced Message Types The ARB format supports placeholders, plurals, and select statements. Define these in your template ARB file with proper metadata: ```json { "hello": "Hello {userName}", "@hello": { "description": "A message with a single parameter", "placeholders": { "userName": { "type": "String", "example": "Bob" } } }, "nWombats": "{count, plural, =0{no wombats} =1{1 wombat} other{{count} wombats}}", "@nWombats": { "description": "A plural message", "placeholders": { "count": { "type": "num", "format": "compact" } } } } ``` Use these in Dart by passing the parameters directly: ```dart Text(l10n.hello('Alice')); Text(l10n.nWombats(notificationCount)); ``` ## Summary - **Add dependencies**: Include `flutter_localizations` (SDK) and `intl` in [`pubspec.yaml`](https://github.com/flutter/skills/blob/main/pubspec.yaml). - **Enable generation**: Set `flutter.generate: true` to trigger automatic code generation. - **Configure builder**: Create [`l10n.yaml`](https://github.com/flutter/skills/blob/main/l10n.yaml) specifying your `arb-dir`, template file, and output location. - **Define translations**: Create ARB files in `lib/l10n/` with metadata for type safety. - **Wire the app**: Import `flutter_gen/gen_l10n/app_localizations.dart` and add `AppLocalizations.delegate` to your `MaterialApp.localizationsDelegates`. - **Access strings**: Use `AppLocalizations.of(context)` to retrieve strongly-typed, localized messages. ## Frequently Asked Questions ### Where are the generated localization files located? When `synthetic-package: true` is set in [`l10n.yaml`](https://github.com/flutter/skills/blob/main/l10n.yaml) (the default), Flutter generates the `app_localizations.dart` file in the synthetic package `flutter_gen/gen_l10n/`. You import this using `import 'package:flutter_gen/gen_l10n/app_localizations.dart';` even though the directory does not exist in your source tree. ### Why is flutter.generate: true required in pubspec.yaml? The `flutter.generate: true` flag activates the Flutter tool's code generation hooks. Without this setting, the localization builder does not run automatically after `flutter pub get`, and the `AppLocalizations` class will not be created or updated when you modify ARB files. ### Can I use Flutter localization without the intl package? No. While `flutter_localizations` provides the delegates and generation infrastructure, the underlying locale-aware formatting, pluralization rules, and ICU message parsing rely on the `intl` package. The generated `AppLocalizations` class uses `intl` functions internally to handle complex message syntax. ### How do I add support for a new language? Create a new ARB file in your configured `arb-dir` (e.g., `lib/l10n/app_fr.arb` for French) containing the translated strings for that locale. Add the corresponding `Locale` to your `MaterialApp.supportedLocales` list, then run `flutter pub get` to regenerate the localizations class. The new locale becomes available immediately through `AppLocalizations.of(context)`.