diff --git a/users/urls.py b/users/urls.py
index bad61f2..59b7fc2 100644
--- a/users/urls.py
+++ b/users/urls.py
@@ -23,4 +23,5 @@ urlpatterns = [
     path('mypage/works/<str:nickname>/', MyPageWorkListAPIView.as_view()),
     path('mypage/my-info/', MyPageMemberInfoAPIView.as_view()),
     path("github/", include(router.urls)),
+    path("portfolio/", UserInfoAPIView.as_view()),
 ]
\ No newline at end of file
diff --git a/users/views.py b/users/views.py
index b3b3684..bacb7ec 100644
--- a/users/views.py
+++ b/users/views.py
@@ -373,6 +373,12 @@ class SetPortofolioRequiredInfoAPIView(APIView):
         custom_url = request.GET.get('custom_url', None)
         if not custom_url:
             return Response({"message": "no url"}, status=status.HTTP_400_BAD_REQUEST)
+        
+        normalized = custom_url.strip().lower()
+
+        if "www" in normalized or "vvvvvv" in normalized:
+            return Response({"message": "custom_url cannot contain 'www'"}, status=status.HTTP_400_BAD_REQUEST)
+    
         if User.objects.filter(custom_url=custom_url).exists():
             return Response({"message": "already used url"}, status=status.HTTP_400_BAD_REQUEST)
         else:
@@ -494,3 +500,21 @@ class MyPageMemberInfoAPIView(APIView):
             return Response(serializer.data, status=status.HTTP_200_OK)
         return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
 
+class UserInfoAPIView(APIView):
+    permission_classes = [AllowAny]
+
+    # 유저 대표 포트폴리오 id 제공
+    def get(self, request):
+        sub_domain = request.query_params.get('sub_domain', '')
+        
+        if not sub_domain:
+            return Response({"message": "no sub domain"}, status=status.HTTP_400_BAD_REQUEST)
+
+        target_user = get_object_or_404(User, custom_url=sub_domain)
+        represent_portfolio = target_user.owned_portfolios.filter(is_represent=True, is_published=True).first()
+        
+        if not represent_portfolio:
+            return Response({"message": "no represent published portfolio"}, status=status.HTTP_404_NOT_FOUND)
+        
+        return Response({"portfolio_id": represent_portfolio.id}, status=status.HTTP_200_OK)
+