flutter_auto_localizations

Effortlessly automate the localization process in your Flutter applications with Flutter Auto Localizations. This CLI tool streamlines the integration of internationalization (i18n) by parsing ARB files and generating the necessary localization code, ensuring a seamless multilingual user experience.

✨ Features

✅ Fully compatible with flutter_localizations

✅ Automatic parsing of ARB files and localization for specified languages

✅ Generates localization delegates and localized string accessors

✅ Supports ICU Plural and Select messages for advanced translations

✅ Customizable configurations via l10n.yaml

✅ Seamless integration with existing Flutter projects

✅ Estimates API costs for translation requests

📦 Installation

1. Enable Flutter Localizations

Add the following to your pubspec.yaml under dev_dependencies if not already present:

dependencies:
  flutter_localizations:
    sdk: flutter

Enable code generation by adding this under flutter:

flutter:
  generate: true

2. Add the package

Add the following under dev_dependencies in pubspec.yaml:

dev_dependencies:
  flutter_auto_localizations: ^1.0.0

Then, run:

flutter pub get

⚙️ Configuration

1. Configure l10n.yaml

Create a l10n.yaml file in the root of your project and define your localization settings:

arb-dir: lib/l10n
template-arb-file: app_en.arb
output-localization-file: app_localizations.dart
enable-cache: true # Enables caching for optimized translations

languages:
  - si
  - es
  - fr

🔹 Find supported translation languages here.

2. Create the ARB Directory and Default ARB File

After configuring l10n.yaml, create the localization directory and the default ARB file as specified in arb-dir and template-arb-file.

📌 Example app_en.arb File

{
  "title": "Welcome to My App",
  "welcomeMessage": "Hello, {username}!",
  "cartItems": "{count, plural, zero{Your cart is empty} one{You have one item} other{You have {count} items}}",
  "@cartItems": {
    "description": "Pluralized message for cart items."
  }
}

2. Set Up Google Cloud Translation API

To enable automatic translations, follow these steps:

🔑 Create an API Key & Configure Google Cloud Console

Create an API key from Google Cloud Console.
Enable Cloud Translation API.
Billing must be enabled to use this API.

💡 Google offers free translations for the first 500,000 characters per month (equivalent to $10 free credit monthly). After 500,000 characters, the cost is $20 per million characters.

⚠️ Important: These prices and quota might be changed over time. Always check the latest pricing details.

3. Store API Key Securely**

Create a .env file in your project’s root directory.
Add your API key like this:

GOOGLE_TRANSLATE_API_KEY=<put_your_api_key>

⚠️ Important: Add .env to your .gitignore file to avoid exposing your API key in version control.

🚀 Usage

After configuration, generate localization files by running:

dart run flutter_auto_localizations

🛠️ Example Usage in Flutter

Once localization files are generated, use them in your Flutter app:

import 'package:flutter/material.dart';
import 'generated/app_localizations.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      localizationsDelegates: AppLocalizations.localizationsDelegates,
      supportedLocales: AppLocalizations.supportedLocales,
      home: HomePage(),
    );
  }
}

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final localizations = AppLocalizations.of(context)!;
    return Scaffold(
      appBar: AppBar(
        title: Text(localizations.title),
      ),
      body: Center(
        child: Text(localizations.welcomeMessage),
      ),
    );
  }
}

🛠 Configuration Options

Below is a detailed explanation of all possible configurations in the l10n.yaml file.

🌐 Global Configuration

🔹 enable-cache

enable-cache: true

Enables caching to reduce API calls and optimize translations.
Set to false to always fetch fresh translations.

🔹 arb-dir

arb-dir: lib/l10n

Defines the directory where .arb (Application Resource Bundle) files are stored.

🔹 template-arb-file

template-arb-file: app_en.arb

Specifies the base ARB file used as a reference for translations.
Must be located inside the arb-dir directory.
The default language is inferred from this filename (app_en.arb → en).

🔹 output-localization-file

output-localization-file: app_localizations.dart

Defines the Dart file where the localization implementation will be generated.

🔹 languages

languages:
  - en
  - es
  - fr

A list of languages to be generated from the template ARB file.
ARB file will be generated to each specified language.
Supported languages: See Google Cloud Translate Docs

🔹 global-ignore-phrases

global-ignore-phrases:
  - "Technology"
  - "Notebook"
  - "Settings"

These settings help control how translations handle specific words and phrases.
Defines words/phrases that should never be translated, across all keys.
Useful for brand names, technical terms, or proper nouns.
These phrases will always remain in their original language and case sensitive.

📌 Example

If Technology is in global_ignore_phrases, then:

English: "Latest Technology"
Spanish Translation: "Última Technology" (Technology remains unchanged!)

📍 Key Level Configuration

🔹 key-config (Per-Key Customization)

Defines per-key translation behavior by allowing you to override global settings or specify custom ignore phrases for individual translation keys.

To customize translations for a specific key, use the key name from your ARB file and define configurations under key-config.

📌 How it works

Each key in your ARB file can have its own configuration.
Use skip-global-ignore to bypass the global ignore list.
Use key-ignore-phrases to specify words that should not be translated for that key.

📌 Example ARB File (app_en.arb)

{
  "productDescription": "This is a premium service available worldwide.",
  "specialOffer": "This exclusive deal is available for a limited time!"
}

📌 Corresponding l10n.yaml Configuration

key-config:
  productDescription:
    skip-global-ignore: true

  specialOffer:
    key-ignore-phrases:
      - "exclusive"
      - "deal"

🔹 skip-global-ignore

key-config:
  productDescription:
    skip-global-ignore: true

skip-global-ignore: true forces everything in productDescription to be translated without considering global-ignore-phrases.
Useful when some keys need full translations without restrictions.

📌 Example Behavior

Suppose "service" is in global_ignore_phrases.
Normally, it would not be translated.
But for productDescription, it will be translated because skip-global-ignore: true.

🔹 key-ignore-phrases

key-config:
  specialOffer:
    key-ignore-phrases:
      - "exclusive"
      - "deal"

Unlike global-ignore-phrases, this only affects one key.
"exclusive" and "deal" will not be translated, but everything else will.

📌 Example Behavior

English: "This exclusive deal is available for a limited time!"
Spanish Translation: "¡Esta exclusive deal está disponible por un tiempo limitado!" ("exclusive" and "deal" remain in English.)

🔹 no-cache

key-config:
  specialOffer:
    no-cache: true

The specific key will not use the cached translations, but always use the API for translation.

🔹 ignore

key-config:
  specialOffer:
    ignore: true

The specific key will be excluded from the translation.

📌 Key Differences Between Global and Key-Level Ignores

Feature	global-ignore-phrases	key-ignore-phrases
Affects all keys	✅ Yes	❌ No (only one key)
Can be bypassed?	✅ Yes (skip-global-ignore: true)	❌ No
Good for	Brand names, technical terms	Case-by-case exceptions

📌 Example Full l10n.yaml Configuration

arb-dir: lib/l10n
template-arb-file: app_en.arb
output-localization-file: app_localizations.dart
enable-cache: true

languages:
  - en
  - es
  - fr

global-ignore-phrases:
  - "Flutter"
  - "Dart"
  - "Running Man"

key_config:
  productDescription:
    skip-global-ignore: true
  specialCase:
    key-ignore-phrases:
      - "exclusive"
      - "deal"
  cartItems:
    ignore: true
  cartEmptyState:
    no-cache: true

📌 This setup ensures

"Flutter", "Dart", and "Running Man" will never be translated.
"exclusive" and "deal" will be ignored only in specialCase.
productDescription will translate everything, not considering global-ignore-phrases.
cartItems will not be translated.
cartEmptyState will be translated, however it will not consider cached translations.

💡 Contributing

Contributions are welcome! If you find a bug or want to suggest an improvement, please open an issue or submit a pull request on GitHub.

☕ Support the Project

If you find this package helpful and want to support its development, consider buying me a coffee!

Your support helps keep the project updated and maintained. Thank you! ❤️

✨ Features

📦 Installation

1. Enable Flutter Localizations

2. Add the package

⚙️ Configuration

1. Configure l10n.yaml

🔹 Find supported translation languages here.

2. Create the ARB Directory and Default ARB File

📌 Example app_en.arb File

2. Set Up Google Cloud Translation API

🔑 Create an API Key & Configure Google Cloud Console

3. Store API Key Securely**

🚀 Usage

🛠️ Example Usage in Flutter

🛠 Configuration Options

🌐 Global Configuration

🔹 enable-cache

🔹 arb-dir

🔹 template-arb-file

🔹 output-localization-file

🔹 languages

🔹 global-ignore-phrases

📌 Example

📍 Key Level Configuration

🔹 key-config (Per-Key Customization)

📌 How it works

📌 Example ARB File (app_en.arb)

📌 Corresponding l10n.yaml Configuration

🔹 skip-global-ignore

📌 Example Behavior

🔹 key-ignore-phrases

📌 Example Behavior

🔹 no-cache

🔹 ignore

📌 Key Differences Between Global and Key-Level Ignores

📌 Example Full l10n.yaml Configuration

📌 This setup ensures

💡 Contributing

☕ Support the Project

Libraries

flutter_auto_localizations package