diff --git a/lib/core/app_initializer.dart b/lib/core/app_initializer.dart
new file mode 100644
index 0000000..0628ab8
--- /dev/null
+++ b/lib/core/app_initializer.dart
@@ -0,0 +1,156 @@
+import 'package:flutter_dotenv/flutter_dotenv.dart';
+import 'package:firebase_core/firebase_core.dart';
+import '../config/config_loader.dart';
+import '../data/local/local_storage_service.dart';
+import '../data/nostr/nostr_service.dart';
+import '../data/sync/sync_engine.dart';
+import '../data/firebase/firebase_service.dart';
+import '../data/session/session_service.dart';
+import '../data/immich/immich_service.dart';
+import 'app_services.dart';
+import 'service_locator.dart';
+import 'logger.dart';
+
+/// Initializes all application services.
+/// 
+/// Handles the complete initialization sequence:
+/// 1. Load environment configuration
+/// 2. Initialize Firebase (if enabled)
+/// 3. Initialize local storage
+/// 4. Initialize Nostr service and sync engine
+/// 5. Initialize Immich service
+/// 6. Initialize Firebase service (if enabled)
+/// 7. Initialize session service
+/// 8. Register all services with ServiceLocator
+class AppInitializer {
+  /// Initializes all application services.
+  /// 
+  /// [environment] - The environment to use ('dev' or 'prod').
+  /// 
+  /// Returns an [AppServices] instance with all initialized services.
+  /// 
+  /// Throws if initialization fails.
+  static Future<AppServices> initialize({
+    String environment = 'dev',
+  }) async {
+    Logger.info('Starting application initialization...');
+
+    // Load .env file (optional - falls back to defaults if not found)
+    try {
+      await dotenv.load(fileName: '.env');
+      Logger.debug('.env file loaded successfully');
+    } catch (e) {
+      Logger.warning('.env file not found, using default values: $e');
+    }
+
+    // Load configuration based on environment
+    final config = ConfigLoader.load(environment);
+    Logger.setEnabled(config.enableLogging);
+    Logger.info('Configuration loaded for environment: $environment');
+
+    // Initialize Firebase if enabled
+    if (config.firebaseConfig.enabled) {
+      try {
+        await Firebase.initializeApp();
+        Logger.info('Firebase initialized successfully');
+      } catch (e) {
+        Logger.error(
+          'Firebase initialization failed: $e',
+          e,
+        );
+        Logger.warning(
+          'Note: Firebase requires google-services.json (Android) and GoogleService-Info.plist (iOS)',
+        );
+      }
+    }
+
+    // Initialize local storage service
+    Logger.debug('Initializing local storage service...');
+    final storageService = LocalStorageService();
+    try {
+      await storageService.initialize();
+      Logger.info('Local storage service initialized');
+    } catch (e) {
+      Logger.error('Failed to initialize storage: $e', e);
+      rethrow;
+    }
+
+    // Initialize Nostr service and sync engine
+    Logger.debug('Initializing Nostr service...');
+    final nostrService = NostrService();
+    final nostrKeyPair = nostrService.generateKeyPair();
+    
+    final syncEngine = SyncEngine(
+      localStorage: storageService,
+      nostrService: nostrService,
+      nostrKeyPair: nostrKeyPair,
+    );
+    Logger.info('Nostr service and sync engine initialized');
+
+    // Load relays from config
+    for (final relayUrl in config.nostrRelays) {
+      nostrService.addRelay(relayUrl);
+    }
+    Logger.debug('Loaded ${config.nostrRelays.length} relay(s) from config');
+
+    // Initialize Immich service
+    Logger.debug('Initializing Immich service...');
+    final immichService = ImmichService(
+      baseUrl: config.immichBaseUrl,
+      apiKey: config.immichApiKey,
+      localStorage: storageService,
+    );
+    Logger.info('Immich service initialized');
+
+    // Initialize Firebase service if enabled
+    FirebaseService? firebaseService;
+    if (config.firebaseConfig.enabled) {
+      try {
+        Logger.debug('Initializing Firebase service...');
+        firebaseService = FirebaseService(
+          config: config.firebaseConfig,
+          localStorage: storageService,
+        );
+        await firebaseService.initialize();
+        Logger.info('Firebase service initialized: ${firebaseService.isEnabled}');
+      } catch (e) {
+        Logger.error('Firebase service initialization failed: $e', e);
+        firebaseService = null;
+      }
+    }
+
+    // Initialize SessionService with Firebase and Nostr integration
+    Logger.debug('Initializing session service...');
+    final sessionService = SessionService(
+      localStorage: storageService,
+      syncEngine: syncEngine,
+      firebaseService: firebaseService,
+      nostrService: nostrService,
+    );
+    Logger.info('Session service initialized');
+
+    // Create AppServices container
+    final appServices = AppServices(
+      localStorageService: storageService,
+      nostrService: nostrService,
+      syncEngine: syncEngine,
+      firebaseService: firebaseService,
+      sessionService: sessionService,
+      immichService: immichService,
+    );
+
+    // Register all services with ServiceLocator
+    ServiceLocator.instance.registerServices(
+      localStorageService: storageService,
+      nostrService: nostrService,
+      syncEngine: syncEngine,
+      firebaseService: firebaseService,
+      sessionService: sessionService,
+      immichService: immichService,
+    );
+
+    Logger.info('Application initialization completed successfully');
+    return appServices;
+  }
+}
+
diff --git a/lib/core/app_services.dart b/lib/core/app_services.dart
new file mode 100644
index 0000000..055e004
--- /dev/null
+++ b/lib/core/app_services.dart
@@ -0,0 +1,55 @@
+import '../data/local/local_storage_service.dart';
+import '../data/nostr/nostr_service.dart';
+import '../data/sync/sync_engine.dart';
+import '../data/firebase/firebase_service.dart';
+import '../data/session/session_service.dart';
+import '../data/immich/immich_service.dart';
+
+/// Container for all application services.
+/// 
+/// Holds references to all initialized services and provides
+/// a convenient way to dispose of them.
+class AppServices {
+  /// Local storage service.
+  final LocalStorageService localStorageService;
+
+  /// Nostr service.
+  final NostrService? nostrService;
+
+  /// Sync engine.
+  final SyncEngine? syncEngine;
+
+  /// Firebase service.
+  final FirebaseService? firebaseService;
+
+  /// Session service.
+  final SessionService? sessionService;
+
+  /// Immich service.
+  final ImmichService? immichService;
+
+  /// Creates an [AppServices] instance.
+  AppServices({
+    required this.localStorageService,
+    this.nostrService,
+    this.syncEngine,
+    this.firebaseService,
+    this.sessionService,
+    this.immichService,
+  });
+
+  /// Disposes of all services that need cleanup.
+  Future<void> dispose() async {
+    syncEngine?.dispose();
+    nostrService?.dispose();
+    firebaseService?.dispose();
+    
+    // Close storage service
+    try {
+      await localStorageService.close();
+    } catch (e) {
+      // Ignore errors during cleanup
+    }
+  }
+}
+
diff --git a/lib/core/constants/app_constants.dart b/lib/core/constants/app_constants.dart
new file mode 100644
index 0000000..08b448d
--- /dev/null
+++ b/lib/core/constants/app_constants.dart
@@ -0,0 +1,24 @@
+/// Application-wide constants.
+class AppConstants {
+  /// Application name.
+  static const String appName = 'App Boilerplate';
+
+  /// Default connection timeout duration.
+  static const Duration connectionTimeout = Duration(seconds: 3);
+
+  /// Default health check timeout duration.
+  static const Duration healthCheckTimeout = Duration(seconds: 2);
+
+  /// Default retry delay for operations.
+  static const Duration retryDelay = Duration(seconds: 1);
+
+  /// Maximum number of retries for failed operations.
+  static const int maxRetries = 3;
+
+  /// Maximum queue size for sync operations.
+  static const int maxQueueSize = 100;
+
+  /// Private constructor to prevent instantiation.
+  AppConstants._();
+}
+
diff --git a/lib/core/constants/route_names.dart b/lib/core/constants/route_names.dart
new file mode 100644
index 0000000..285d75c
--- /dev/null
+++ b/lib/core/constants/route_names.dart
@@ -0,0 +1,24 @@
+/// Route names for navigation.
+class RouteNames {
+  /// Home route.
+  static const String home = '/home';
+
+  /// Immich route.
+  static const String immich = '/immich';
+
+  /// Nostr Events route.
+  static const String nostrEvents = '/nostr-events';
+
+  /// Session route.
+  static const String session = '/session';
+
+  /// Settings route.
+  static const String settings = '/settings';
+
+  /// Relay Management route.
+  static const String relayManagement = '/relay-management';
+
+  /// Private constructor to prevent instantiation.
+  RouteNames._();
+}
+
diff --git a/lib/core/exceptions/exceptions.dart b/lib/core/exceptions/exceptions.dart
new file mode 100644
index 0000000..dbccf0f
--- /dev/null
+++ b/lib/core/exceptions/exceptions.dart
@@ -0,0 +1,10 @@
+/// Barrel file for all exceptions.
+/// 
+/// Import this file to get access to all exception classes.
+export 'firebase_exception.dart' show FirebaseServiceException;
+export 'immich_exception.dart';
+export 'invalid_environment_exception.dart';
+export 'nostr_exception.dart';
+export 'session_exception.dart';
+export 'sync_exception.dart';
+
diff --git a/lib/core/exceptions/firebase_exception.dart b/lib/core/exceptions/firebase_exception.dart
new file mode 100644
index 0000000..48c5609
--- /dev/null
+++ b/lib/core/exceptions/firebase_exception.dart
@@ -0,0 +1,15 @@
+/// Exception thrown when Firebase service operations fail.
+/// 
+/// Note: This is different from Firebase SDK's FirebaseException.
+/// This exception is used for our FirebaseService wrapper.
+class FirebaseServiceException implements Exception {
+  /// Error message.
+  final String message;
+
+  /// Creates a [FirebaseServiceException] with the provided message.
+  FirebaseServiceException(this.message);
+
+  @override
+  String toString() => 'FirebaseServiceException: $message';
+}
+
diff --git a/lib/core/exceptions/immich_exception.dart b/lib/core/exceptions/immich_exception.dart
new file mode 100644
index 0000000..fb0b898
--- /dev/null
+++ b/lib/core/exceptions/immich_exception.dart
@@ -0,0 +1,20 @@
+/// Exception thrown when Immich API operations fail.
+class ImmichException implements Exception {
+  /// Error message.
+  final String message;
+
+  /// HTTP status code if available.
+  final int? statusCode;
+
+  /// Creates an [ImmichException] with the provided message.
+  ImmichException(this.message, [this.statusCode]);
+
+  @override
+  String toString() {
+    if (statusCode != null) {
+      return 'ImmichException: $message (Status: $statusCode)';
+    }
+    return 'ImmichException: $message';
+  }
+}
+
diff --git a/lib/core/exceptions/invalid_environment_exception.dart b/lib/core/exceptions/invalid_environment_exception.dart
new file mode 100644
index 0000000..37d82dd
--- /dev/null
+++ b/lib/core/exceptions/invalid_environment_exception.dart
@@ -0,0 +1,15 @@
+/// Exception thrown when an invalid environment is provided to [ConfigLoader].
+class InvalidEnvironmentException implements Exception {
+  /// The invalid environment that was provided.
+  final String environment;
+
+  /// Creates an [InvalidEnvironmentException] with the provided environment.
+  InvalidEnvironmentException(this.environment);
+
+  @override
+  String toString() {
+    return 'InvalidEnvironmentException: Invalid environment "$environment". '
+        'Valid environments are: dev, prod';
+  }
+}
+
diff --git a/lib/core/exceptions/nostr_exception.dart b/lib/core/exceptions/nostr_exception.dart
new file mode 100644
index 0000000..2b4405e
--- /dev/null
+++ b/lib/core/exceptions/nostr_exception.dart
@@ -0,0 +1,12 @@
+/// Exception thrown when Nostr operations fail.
+class NostrException implements Exception {
+  /// Error message.
+  final String message;
+
+  /// Creates a [NostrException] with the provided message.
+  NostrException(this.message);
+
+  @override
+  String toString() => 'NostrException: $message';
+}
+
diff --git a/lib/core/exceptions/session_exception.dart b/lib/core/exceptions/session_exception.dart
new file mode 100644
index 0000000..28a9a0e
--- /dev/null
+++ b/lib/core/exceptions/session_exception.dart
@@ -0,0 +1,12 @@
+/// Exception thrown when session operations fail.
+class SessionException implements Exception {
+  /// Error message.
+  final String message;
+
+  /// Creates a [SessionException] with the provided message.
+  SessionException(this.message);
+
+  @override
+  String toString() => 'SessionException: $message';
+}
+
diff --git a/lib/core/exceptions/sync_exception.dart b/lib/core/exceptions/sync_exception.dart
new file mode 100644
index 0000000..4fbf26a
--- /dev/null
+++ b/lib/core/exceptions/sync_exception.dart
@@ -0,0 +1,12 @@
+/// Exception thrown when sync operations fail.
+class SyncException implements Exception {
+  /// Error message.
+  final String message;
+
+  /// Creates a [SyncException] with the provided message.
+  SyncException(this.message);
+
+  @override
+  String toString() => 'SyncException: $message';
+}
+
diff --git a/lib/core/logger.dart b/lib/core/logger.dart
new file mode 100644
index 0000000..7b3bd90
--- /dev/null
+++ b/lib/core/logger.dart
@@ -0,0 +1,82 @@
+import 'package:flutter/foundation.dart';
+
+/// Log levels for different types of messages.
+enum LogLevel {
+  /// Debug messages (only in debug mode).
+  debug,
+  
+  /// Informational messages.
+  info,
+  
+  /// Warning messages.
+  warning,
+  
+  /// Error messages (always shown).
+  error,
+}
+
+/// Centralized logging service for the application.
+/// 
+/// Provides consistent logging across the app with different log levels.
+/// In production, only errors are logged unless explicitly enabled.
+class Logger {
+  /// Whether logging is enabled (can be configured via config).
+  static bool _enabled = kDebugMode;
+
+  /// Enable or disable logging.
+  static void setEnabled(bool enabled) {
+    _enabled = enabled;
+  }
+
+  /// Logs a message with the specified level.
+  /// 
+  /// [level] - The log level (debug, info, warning, error).
+  /// [message] - The message to log.
+  /// [error] - Optional error object.
+  /// [stackTrace] - Optional stack trace.
+  static void log(
+    LogLevel level,
+    String message, [
+    Object? error,
+    StackTrace? stackTrace,
+  ]) {
+    // Always log errors, respect enabled flag for others
+    if (!_enabled && level != LogLevel.error) {
+      return;
+    }
+
+    final prefix = '[${level.name.toUpperCase()}]';
+    final timestamp = DateTime.now().toIso8601String();
+    
+    debugPrint('$timestamp $prefix $message');
+    
+    if (error != null) {
+      debugPrint('$timestamp $prefix Error: $error');
+    }
+    
+    if (stackTrace != null) {
+      debugPrint('$timestamp $prefix Stack trace: $stackTrace');
+    }
+  }
+
+  /// Logs a debug message (only in debug mode).
+  static void debug(String message) {
+    log(LogLevel.debug, message);
+  }
+
+  /// Logs an informational message.
+  static void info(String message) {
+    log(LogLevel.info, message);
+  }
+
+  /// Logs a warning message.
+  static void warning(String message, [Object? error]) {
+    log(LogLevel.warning, message, error);
+  }
+
+  /// Logs an error message (always shown).
+  static void error(String message, [Object? error, StackTrace? stackTrace]) {
+    log(LogLevel.error, message, error, stackTrace);
+  }
+}
+
diff --git a/lib/core/service_locator.dart b/lib/core/service_locator.dart
new file mode 100644
index 0000000..298d7d7
--- /dev/null
+++ b/lib/core/service_locator.dart
@@ -0,0 +1,85 @@
+/// Service locator for dependency injection.
+/// 
+/// Provides a centralized registry for all application services,
+/// making it easy to access services throughout the app
+/// and swap implementations for testing.
+class ServiceLocator {
+  /// Private constructor to prevent instantiation.
+  ServiceLocator._();
+
+  /// Singleton instance.
+  static final ServiceLocator instance = ServiceLocator._();
+
+  /// Local storage service.
+  dynamic _localStorageService;
+
+  /// Nostr service.
+  dynamic _nostrService;
+
+  /// Sync engine.
+  dynamic _syncEngine;
+
+  /// Firebase service.
+  dynamic _firebaseService;
+
+  /// Session service.
+  dynamic _sessionService;
+
+  /// Immich service.
+  dynamic _immichService;
+
+  /// Registers all services with the locator.
+  /// 
+  /// All services are optional and can be null if not configured.
+  void registerServices({
+    dynamic localStorageService,
+    dynamic nostrService,
+    dynamic syncEngine,
+    dynamic firebaseService,
+    dynamic sessionService,
+    dynamic immichService,
+  }) {
+    _localStorageService = localStorageService;
+    _nostrService = nostrService;
+    _syncEngine = syncEngine;
+    _firebaseService = firebaseService;
+    _sessionService = sessionService;
+    _immichService = immichService;
+  }
+
+  /// Gets the local storage service.
+  /// 
+  /// Throws [StateError] if service is not registered.
+  dynamic get localStorageService {
+    if (_localStorageService == null) {
+      throw StateError('LocalStorageService not registered');
+    }
+    return _localStorageService;
+  }
+
+  /// Gets the Nostr service (nullable).
+  dynamic get nostrService => _nostrService;
+
+  /// Gets the sync engine (nullable).
+  dynamic get syncEngine => _syncEngine;
+
+  /// Gets the Firebase service (nullable).
+  dynamic get firebaseService => _firebaseService;
+
+  /// Gets the session service (nullable).
+  dynamic get sessionService => _sessionService;
+
+  /// Gets the Immich service (nullable).
+  dynamic get immichService => _immichService;
+
+  /// Clears all registered services (useful for testing).
+  void reset() {
+    _localStorageService = null;
+    _nostrService = null;
+    _syncEngine = null;
+    _firebaseService = null;
+    _sessionService = null;
+    _immichService = null;
+  }
+}
+