diff --git a/packages/deriv_auth/lib/core/services/token/services/base_token_service.dart b/packages/deriv_auth/lib/core/services/token/services/base_token_service.dart
index e7f71f029..56f251c2e 100644
--- a/packages/deriv_auth/lib/core/services/token/services/base_token_service.dart
+++ b/packages/deriv_auth/lib/core/services/token/services/base_token_service.dart
@@ -9,8 +9,8 @@ abstract class BaseTokenService {
   Future<GetTokensResponseModel> getUserTokens({
     required GetTokensRequestModel request,
     required BaseHttpClient client,
-    required String userAgent,
     required String jwtToken,
     required AuthConnectionInfo connectionInfo,
+    String? userAgent,
   });
 }
diff --git a/packages/deriv_auth/lib/core/services/token/services/deriv_token_service.dart b/packages/deriv_auth/lib/core/services/token/services/deriv_token_service.dart
index aa19418c6..41063a3d6 100644
--- a/packages/deriv_auth/lib/core/services/token/services/deriv_token_service.dart
+++ b/packages/deriv_auth/lib/core/services/token/services/deriv_token_service.dart
@@ -10,9 +10,9 @@ class DerivTokenService implements BaseTokenService {
   Future<GetTokensResponseModel> getUserTokens({
     required GetTokensRequestModel request,
     required BaseHttpClient client,
-    required String userAgent,
     required String jwtToken,
     required AuthConnectionInfo connectionInfo,
+    String? userAgent,
   }) async {
     /// Extract login url from connection info.
     final String baseUrl = 'https://${connectionInfo.endpoint}/oauth2/api/v1';
@@ -25,7 +25,7 @@ class DerivTokenService implements BaseTokenService {
           request.copyWith(appId: int.parse(connectionInfo.appId)).toJson(),
       headers: <String, String>{
         'Authorization': 'Bearer $jwtToken',
-        'User-Agent': userAgent,
+        'User-Agent': userAgent ?? '',
       },
     );
 
diff --git a/packages/deriv_auth/lib/features/auth/cubit/deriv_auth_cubit.dart b/packages/deriv_auth/lib/features/auth/cubit/deriv_auth_cubit.dart
index 1020991fd..cfdd6ba9f 100644
--- a/packages/deriv_auth/lib/features/auth/cubit/deriv_auth_cubit.dart
+++ b/packages/deriv_auth/lib/features/auth/cubit/deriv_auth_cubit.dart
@@ -95,7 +95,7 @@ class DerivAuthCubit extends Cubit<DerivAuthState> implements DerivAuthIO {
     try {
       final String userAgent = await getUserAgent();
       final AuthorizeEntity authorizeEntity =
-          await authService.onLoginRequest(request, userAgent);
+          await authService.onLoginRequest(request, userAgent: userAgent);
       final LandingCompanyEntity landingCompanyEntity =
           await authService.getLandingCompany(authorizeEntity.country);
       _isUserMigrated = _checkUserMigrated(authorizeEntity);
diff --git a/packages/deriv_auth/lib/features/auth/services/base_auth_service.dart b/packages/deriv_auth/lib/features/auth/services/base_auth_service.dart
index 7cefdf0bd..05d5541d3 100644
--- a/packages/deriv_auth/lib/features/auth/services/base_auth_service.dart
+++ b/packages/deriv_auth/lib/features/auth/services/base_auth_service.dart
@@ -7,9 +7,9 @@ import 'package:deriv_auth/core/services/token/models/login_request.dart';
 abstract class BaseAuthService {
   /// Function before logging user in.
   Future<AuthorizeEntity> onLoginRequest(
-    GetTokensRequestModel request,
-    String userAgent,
-  );
+    GetTokensRequestModel request, {
+    String? userAgent,
+  });
 
   /// Log in a user with [token].
   Future<AuthorizeEntity> login(
diff --git a/packages/deriv_auth/lib/features/auth/services/deriv_auth_service.dart b/packages/deriv_auth/lib/features/auth/services/deriv_auth_service.dart
index fde589097..285e68ca0 100644
--- a/packages/deriv_auth/lib/features/auth/services/deriv_auth_service.dart
+++ b/packages/deriv_auth/lib/features/auth/services/deriv_auth_service.dart
@@ -41,10 +41,10 @@ class DerivAuthService extends BaseAuthService {
 
   @override
   Future<AuthorizeEntity> onLoginRequest(
-    GetTokensRequestModel request,
-    String userAgent, [
+    GetTokensRequestModel request, {
+    String? userAgent,
     Function? onInvalidJwtToken,
-  ]) async {
+  }) async {
     try {
       final String jwtToken = await jwtService.getJwtToken();
 
@@ -80,7 +80,7 @@ class DerivAuthService extends BaseAuthService {
 
         jwtService.clearJwtToken();
 
-        return onLoginRequest(request, userAgent);
+        return onLoginRequest(request, userAgent: userAgent);
       } else {
         throw _mapHttpErrorToDerivAuthError(error);
       }
diff --git a/packages/deriv_auth/test/core/services/token/services/deriv_token_service_test.dart b/packages/deriv_auth/test/core/services/token/services/deriv_token_service_test.dart
index f5d1779b4..826f72c9c 100644
--- a/packages/deriv_auth/test/core/services/token/services/deriv_token_service_test.dart
+++ b/packages/deriv_auth/test/core/services/token/services/deriv_token_service_test.dart
@@ -42,7 +42,6 @@ void main() {
       final GetTokensResponseModel response = await _tokenService.getUserTokens(
         request: GetTokensRequestModel(),
         client: _client,
-        userAgent: 'user_agent',
         jwtToken: _jwtToken,
         connectionInfo: _connectionInfo,
       );
diff --git a/packages/deriv_auth/test/features/auth/cubit/deriv_auth_cubit_test.dart b/packages/deriv_auth/test/features/auth/cubit/deriv_auth_cubit_test.dart
index fcad1b149..0c3254c1b 100644
--- a/packages/deriv_auth/test/features/auth/cubit/deriv_auth_cubit_test.dart
+++ b/packages/deriv_auth/test/features/auth/cubit/deriv_auth_cubit_test.dart
@@ -90,7 +90,7 @@ void main() {
           () {
         registerFallbackValue(GetTokensRequestModel(type: AuthType.system));
 
-        when(() => service.onLoginRequest(any(), any())).thenAnswer(
+        when(() => service.onLoginRequest(any())).thenAnswer(
             (_) => Future<AuthorizeEntity>.value(mockedValidAuthorizeEntity));
 
         final List<TypeMatcher<DerivAuthState>> expectedResponse =
@@ -106,7 +106,7 @@ void main() {
 
         authCubit.systemLogin(email: 'email', password: 'password');
 
-        verify(() => service.onLoginRequest(any(), any())).called(1);
+        verify(() => service.onLoginRequest(any())).called(1);
       });
 
       test(
@@ -114,7 +114,7 @@ void main() {
           () {
         registerFallbackValue(GetTokensRequestModel(type: AuthType.social));
 
-        when(() => service.onLoginRequest(any(), any())).thenAnswer(
+        when(() => service.onLoginRequest(any())).thenAnswer(
             (_) => Future<AuthorizeEntity>.value(mockedValidAuthorizeEntity));
 
         final List<TypeMatcher<DerivAuthState>> expectedResponse =
@@ -130,7 +130,7 @@ void main() {
 
         authCubit.socialLogin(oneAllConnectionToken: 'token');
 
-        verify(() => service.onLoginRequest(any(), any())).called(1);
+        verify(() => service.onLoginRequest(any())).called(1);
       });
 
       test(
@@ -138,7 +138,7 @@ void main() {
           () {
         registerFallbackValue(GetTokensRequestModel(type: AuthType.social));
 
-        when(() => service.onLoginRequest(any(), any())).thenAnswer(
+        when(() => service.onLoginRequest(any())).thenAnswer(
             (_) => Future<AuthorizeEntity>.value(mockedValidAuthorizeEntity));
 
         final List<TypeMatcher<DerivAuthState>> expectedResponse =
@@ -156,11 +156,11 @@ void main() {
           socialAuthDto: mockSocialAuthDto,
         );
 
-        verify(() => service.onLoginRequest(any(), any())).called(1);
+        verify(() => service.onLoginRequest(any())).called(1);
       });
 
       test('should emit [AuthLoggedInState] upon a successful otp login.', () {
-        when(() => service.onLoginRequest(any(), any())).thenAnswer(
+        when(() => service.onLoginRequest(any())).thenAnswer(
             (_) => Future<AuthorizeEntity>.value(mockedValidAuthorizeEntity));
 
         final List<TypeMatcher<DerivAuthState>> expectedResponse =
@@ -175,15 +175,14 @@ void main() {
         );
         authCubit.systemLogin(email: 'email', password: 'pass', otp: 'otp');
 
-        verify(() => service.onLoginRequest(any(), any())).called(1);
+        verify(() => service.onLoginRequest(any())).called(1);
       });
 
       test('should emit [AuthErrorState] when an exception occurs in service.',
           () {
         registerFallbackValue(GetTokensRequestModel(type: AuthType.system));
 
-        when(() => service.onLoginRequest(any(), any()))
-            .thenThrow(DerivAuthException(
+        when(() => service.onLoginRequest(any())).thenThrow(DerivAuthException(
           message: 'message',
           type: AuthErrorType.expiredAccount,
         ));
@@ -201,7 +200,7 @@ void main() {
 
         authCubit.systemLogin(email: 'email', password: 'pass');
 
-        verify(() => service.onLoginRequest(any(), any())).called(1);
+        verify(() => service.onLoginRequest(any())).called(1);
       });
       test('should emit [AuthLoggedOutState] upon a successful logout.', () {
         when(() => service.logout()).thenAnswer((_) => Future<void>.value());
diff --git a/packages/deriv_auth/test/features/auth/service/deriv_auth_service_test.dart b/packages/deriv_auth/test/features/auth/service/deriv_auth_service_test.dart
index 902883b94..3930d7011 100644
--- a/packages/deriv_auth/test/features/auth/service/deriv_auth_service_test.dart
+++ b/packages/deriv_auth/test/features/auth/service/deriv_auth_service_test.dart
@@ -60,7 +60,6 @@ void main() {
     when(() => tokenService.getUserTokens(
           request: any(named: 'request'),
           client: any(named: 'client'),
-          userAgent: 'user_agent',
           jwtToken: any(named: 'jwtToken', that: equals(validJwtToken)),
           connectionInfo: any(named: 'connectionInfo'),
         )).thenAnswer(
@@ -76,7 +75,6 @@ void main() {
     when(() => tokenService.getUserTokens(
           request: any(named: 'request'),
           client: any(named: 'client'),
-          userAgent: 'user_agent',
           jwtToken: any(named: 'jwtToken', that: equals(invalidJwtToken)),
           connectionInfo: any(named: 'connectionInfo'),
         )).thenThrow(
@@ -135,7 +133,6 @@ void main() {
             password: 'pass',
             signupProvider: 'signupProvider',
           ),
-          'user_agent',
         );
 
         expect(response.userId, mockedValidAuthorizeEntity.userId);
@@ -162,7 +159,6 @@ void main() {
             signupProvider: 'signupProvider',
             oneAllConnectionToken: 'oneAllConnectionToken',
           ),
-          'user_agent',
         );
 
         expect(response.userId, mockedValidAuthorizeEntity.userId);
@@ -189,7 +185,6 @@ void main() {
             signupProvider: 'signupProvider',
             socialAuthDto: mockSocialAuthDto,
           ),
-          'user_agent',
         );
 
         expect(response.userId, mockedValidAuthorizeEntity.userId);
@@ -218,8 +213,7 @@ void main() {
             password: 'pass',
             signupProvider: 'signupProvider',
           ),
-          'user_agent',
-          () {
+          onInvalidJwtToken: () {
             when(() => jwtService.getJwtToken()).thenAnswer(
               (_) => Future<String>.value(validJwtToken),
             );
@@ -247,7 +241,6 @@ void main() {
         when(() => tokenService.getUserTokens(
               request: any(named: 'request'),
               client: any(named: 'client'),
-              userAgent: 'user_agent',
               jwtToken: any(named: 'jwtToken', that: equals(validJwtToken)),
               connectionInfo: any(named: 'connectionInfo'),
             )).thenThrow(
@@ -266,7 +259,6 @@ void main() {
                 password: 'pass',
                 signupProvider: 'signupProvider',
               ),
-              'user_agent',
             ),
             throwsA(
               isA<DerivAuthException>().having(
@@ -286,7 +278,6 @@ void main() {
         when(() => tokenService.getUserTokens(
               request: any(named: 'request'),
               client: any(named: 'client'),
-              userAgent: 'user_agent',
               jwtToken: any(named: 'jwtToken', that: equals(validJwtToken)),
               connectionInfo: any(named: 'connectionInfo'),
             )).thenThrow(
@@ -305,7 +296,6 @@ void main() {
                 password: 'pass',
                 signupProvider: 'signupProvider',
               ),
-              'user_agent',
             ),
             throwsA(
               isA<DerivAuthException>().having(
@@ -325,7 +315,6 @@ void main() {
         when(() => tokenService.getUserTokens(
               request: any(named: 'request'),
               client: any(named: 'client'),
-              userAgent: 'user_agent',
               jwtToken: any(named: 'jwtToken', that: equals(validJwtToken)),
               connectionInfo: any(named: 'connectionInfo'),
             )).thenThrow(
@@ -344,7 +333,6 @@ void main() {
                 password: 'pass',
                 signupProvider: 'signupProvider',
               ),
-              'user_agent',
             ),
             throwsA(
               isA<DerivAuthException>().having(
@@ -436,7 +424,6 @@ void main() {
         when(() => tokenService.getUserTokens(
               request: any(named: 'request'),
               client: any(named: 'client'),
-              userAgent: 'user_agent',
               jwtToken: any(named: 'jwtToken', that: equals(validJwtToken)),
               connectionInfo: any(named: 'connectionInfo'),
             )).thenThrow(
@@ -455,7 +442,6 @@ void main() {
                 password: 'pass',
                 signupProvider: 'signupProvider',
               ),
-              'user_agent',
             ),
             throwsA(
               isA<DerivAuthException>().having(
@@ -475,7 +461,6 @@ void main() {
         when(() => tokenService.getUserTokens(
               request: any(named: 'request'),
               client: any(named: 'client'),
-              userAgent: 'user_agent',
               jwtToken: any(named: 'jwtToken', that: equals(validJwtToken)),
               connectionInfo: any(named: 'connectionInfo'),
             )).thenThrow(
@@ -494,7 +479,6 @@ void main() {
                 password: 'pass',
                 signupProvider: 'signupProvider',
               ),
-              'user_agent',
             ),
             throwsA(
               isA<DerivAuthException>().having(
@@ -514,7 +498,6 @@ void main() {
         when(() => tokenService.getUserTokens(
               request: any(named: 'request'),
               client: any(named: 'client'),
-              userAgent: 'user_agent',
               jwtToken: any(named: 'jwtToken', that: equals(validJwtToken)),
               connectionInfo: any(named: 'connectionInfo'),
             )).thenThrow(
@@ -533,7 +516,6 @@ void main() {
                 password: 'pass',
                 signupProvider: 'signupProvider',
               ),
-              'user_agent',
             ),
             throwsA(
               isA<DerivAuthException>().having(