Flavor Architecture

• Define three flavors: dev , staging , prod

• Use a single main.dart entry point for all flavors

• Pass flavor-specific configuration via --dart-define-from-file : flutter run --flavor dev --dart-define-from-file=config/dev.json flutter run --flavor staging --dart-define-from-file=config/staging.json flutter run --flavor prod --dart-define-from-file=config/prod.json

• NEVER create separate main_dev.dart , main_staging.dart , main_prod.dart entry points

Config JSON Structure

• Store per-flavor JSON config files in a config/ directory at project root: config/ ├── dev.json ├── staging.json └── prod.json

• Example config/dev.json : { "FLAVOR": "dev", "BASE_URL": "https://api-dev.example.com", "APP_NAME": "MyApp Dev", "ENABLE_LOGGING": "true", "ENABLE_CRASHLYTICS": "false" }

• NEVER put secrets (API keys, signing credentials) in these JSON files — use CI-injected env vars or flutter_secure_storage

• Add config/*.json to .gitignore if they contain any environment-specific secrets; otherwise commit them for team convenience

Entry Point Pattern

// lib/main.dart void main() { const flavor = String.fromEnvironment('FLAVOR', defaultValue: 'dev'); AppConfig.init(flavor: Flavor.fromString(flavor)); runApp(const App()); }

• Read all compile-time values via String.fromEnvironment('KEY') or bool.fromEnvironment('KEY')

• Use a sealed Flavor enum: sealed class Flavor { dev, staging, prod }

• AppConfig is a singleton holding flavor, base URL, feature flags, and Firebase config

Environment Configuration

• Store per-flavor config in a centralized AppConfig class:

• baseUrl — API endpoint per environment

• enableLogging — verbose logging for dev only

• enableCrashlytics — disabled in dev

• appName — display name per flavor (e.g., "MyApp Dev", "MyApp")

• All values come from the JSON file via --dart-define-from-file — NO hardcoded per-flavor logic in Dart code

• NEVER put secrets in the JSON config files — use flutter_secure_storage or CI-injected env vars

Platform-Specific Flavor Setup

Android

• Define flavorDimensions and productFlavors in android/app/build.gradle : flavorDimensions "environment" productFlavors { dev { dimension "environment"; applicationIdSuffix ".dev"; resValue "string", "app_name", "MyApp Dev" } staging { dimension "environment"; applicationIdSuffix ".staging"; resValue "string", "app_name", "MyApp Staging" } prod { dimension "environment"; resValue "string", "app_name", "MyApp" } }

iOS

• Create Xcode schemes for each flavor (Dev, Staging, Prod)

• Use xcconfig files for per-flavor bundle ID, display name, and signing

• Map Flutter flavors to Xcode schemes in ios/Runner.xcodeproj

Firebase Per-Flavor

• Use separate Firebase projects per flavor (dev, staging, prod)

• Place google-services.json (Android) and GoogleService-Info.plist (iOS) in flavor-specific directories

• Use flutterfire configure with --project flag for each environment

Build Commands

Development

flutter run --flavor dev --dart-define-from-file=config/dev.json

Staging

flutter run --flavor staging --dart-define-from-file=config/staging.json

Production release

flutter build appbundle --flavor prod --dart-define-from-file=config/prod.json --release flutter build ipa --flavor prod --dart-define-from-file=config/prod.json --release

Rules

• NEVER hardcode environment-specific values (URLs, API keys, feature flags)

• NEVER commit production secrets to the repository

• Every team member MUST be able to run any flavor locally with a single command

• CI/CD pipelines MUST specify both --flavor and --dart-define-from-file explicitly

• Use a single main.dart — NEVER create separate entry points per flavor