diff --git a/apps/mobile/packages/features/staff/authentication/lib/src/data/repositories_impl/auth_repository_impl.dart b/apps/mobile/packages/features/staff/authentication/lib/src/data/repositories_impl/auth_repository_impl.dart
index d8935c46..00b33378 100644
--- a/apps/mobile/packages/features/staff/authentication/lib/src/data/repositories_impl/auth_repository_impl.dart
+++ b/apps/mobile/packages/features/staff/authentication/lib/src/data/repositories_impl/auth_repository_impl.dart
@@ -1,34 +1,113 @@
-import 'package:krow_data_connect/krow_data_connect.dart';
-import 'package:krow_domain/krow_domain.dart';
+import 'dart:async';
+
+import 'package:firebase_auth/firebase_auth.dart' as firebase;
+import 'package:krow_data_connect/krow_data_connect.dart' as dc;
+import 'package:krow_domain/krow_domain.dart' as domain;
 import '../../domain/repositories/auth_repository_interface.dart';
 
 /// Implementation of [AuthRepositoryInterface].
 class AuthRepositoryImpl implements AuthRepositoryInterface {
-  final AuthRepositoryMock mock;
+  final firebase.FirebaseAuth _firebaseAuth;
+  final dc.ExampleConnector _dataConnect;
 
-  AuthRepositoryImpl({required this.mock});
+  AuthRepositoryImpl({
+    required firebase.FirebaseAuth firebaseAuth,
+    required dc.ExampleConnector dataConnect,
+  }) : _firebaseAuth = firebaseAuth,
+       _dataConnect = dataConnect;
 
   @override
-  Stream<User?> get currentUser => mock.currentUser;
+  Stream<domain.User?> get currentUser => _firebaseAuth
+      .authStateChanges()
+      .map((firebaseUser) {
+        if (firebaseUser == null) {
+          return null;
+        }
+
+        return domain.User(
+          id: firebaseUser.uid,
+          email: firebaseUser.email ?? '',
+          phone: firebaseUser.phoneNumber,
+          role: 'staff',
+        );
+      });
 
   /// Signs in with a phone number and returns a verification ID.
   @override
-  Future<String?> signInWithPhone({required String phoneNumber}) {
-    return mock.signInWithPhone(phoneNumber);
+  Future<String?> signInWithPhone({required String phoneNumber}) async {
+    final completer = Completer<String?>();
+
+    await _firebaseAuth.verifyPhoneNumber(
+      phoneNumber: phoneNumber,
+      verificationCompleted: (_) {},
+      verificationFailed: (e) {
+        if (!completer.isCompleted) {
+          completer.completeError(
+            Exception(e.message ?? 'Phone verification failed.'),
+          );
+        }
+      },
+      codeSent: (verificationId, _) {
+        if (!completer.isCompleted) {
+          completer.complete(verificationId);
+        }
+      },
+      codeAutoRetrievalTimeout: (verificationId) {
+        if (!completer.isCompleted) {
+          completer.complete(verificationId);
+        }
+      },
+    );
+
+    return completer.future;
   }
 
   /// Signs out the current user.
   @override
   Future<void> signOut() {
-    return mock.signOut();
+    return _firebaseAuth.signOut();
   }
 
   /// Verifies an OTP code and returns the authenticated user.
   @override
-  Future<User?> verifyOtp({
+  Future<domain.User?> verifyOtp({
     required String verificationId,
     required String smsCode,
-  }) {
-    return mock.verifyOtp(verificationId, smsCode);
+  }) async {
+    final credential = firebase.PhoneAuthProvider.credential(
+      verificationId: verificationId,
+      smsCode: smsCode,
+    );
+    final userCredential = await _firebaseAuth.signInWithCredential(credential);
+    final firebaseUser = userCredential.user;
+    if (firebaseUser == null) {
+      throw Exception('Phone verification failed, no Firebase user received.');
+    }
+
+    final response = await _dataConnect.getUserById(
+      id: firebaseUser.uid,
+    ).execute();
+    final user = response.data?.user;
+    if (user == null) {
+      await _firebaseAuth.signOut();
+      throw Exception('Authenticated user profile not found in database.');
+    }
+    if (user.userRole != 'STAFF') {
+      await _firebaseAuth.signOut();
+      throw Exception('User is not authorized for this app.');
+    }
+
+    final email = user.email ?? '';
+    if (email.isEmpty) {
+      await _firebaseAuth.signOut();
+      throw Exception('User email is missing in profile data.');
+    }
+
+    return domain.User(
+      id: user.id,
+      email: email,
+      phone: firebaseUser.phoneNumber,
+      role: user.role.stringValue,
+    );
   }
 }
diff --git a/apps/mobile/packages/features/staff/authentication/lib/staff_authentication.dart b/apps/mobile/packages/features/staff/authentication/lib/staff_authentication.dart
index 2c272187..ab9bc99a 100644
--- a/apps/mobile/packages/features/staff/authentication/lib/staff_authentication.dart
+++ b/apps/mobile/packages/features/staff/authentication/lib/staff_authentication.dart
@@ -2,6 +2,7 @@ library staff_authentication;
 
 import 'package:flutter_modular/flutter_modular.dart';
 import 'package:krow_data_connect/krow_data_connect.dart';
+import 'package:firebase_auth/firebase_auth.dart' as firebase;
 import 'package:staff_authentication/src/data/repositories_impl/auth_repository_impl.dart';
 import 'package:staff_authentication/src/domain/repositories/auth_repository_interface.dart';
 import 'package:staff_authentication/src/domain/usecases/sign_in_with_phone_usecase.dart';
@@ -28,7 +29,10 @@ class StaffAuthenticationModule extends Module {
   void binds(Injector i) {
     // Repositories
     i.addLazySingleton<AuthRepositoryInterface>(
-      () => AuthRepositoryImpl(mock: i.get<AuthRepositoryMock>()),
+      () => AuthRepositoryImpl(
+        firebaseAuth: firebase.FirebaseAuth.instance,
+        dataConnect: ExampleConnector.instance,
+      ),
     );
 
     // UseCases