diff --git a/backend/product/views.py b/backend/product/views.py
index 901e9fb..432db49 100644
--- a/backend/product/views.py
+++ b/backend/product/views.py
@@ -163,12 +163,13 @@ class AllProductsView(APIView):
             category_type = request.query_params.get('category_type')
 
             VALID_CATEGORY_TYPES = {'sub', 'main'}
+            products = ProductModel.objects.all()
 
             if category_slug:
                 if category_type not in VALID_CATEGORY_TYPES:
                     return Response(
                         {"detail": "category_type must be one of ['sub', 'main']"},
-                        status=status.HTTP_400_BAD_REQUEST  
+                        status=status.HTTP_400_BAD_REQUEST
                     )
 
                 if category_type == 'sub':
@@ -178,36 +179,48 @@ class AllProductsView(APIView):
                     main_category = get_object_or_404(MainCategoryModel, slug=category_slug)
                     sub_categories = main_category.subcategorys.all()
                     products = ProductModel.objects.filter(category__in=sub_categories)
-            else:
-                products = ProductModel.objects.all()
+            in_stock = request.query_params.get('in_stock')
+            if in_stock is not None:
+                if in_stock.lower() == 'true':
+                    products = products.filter(variants__in_stock__gt=0)
+                elif in_stock.lower() != 'false':
+                    return Response({'detail': 'in_stock must be "true" or "false".'}, status=status.HTTP_400_BAD_REQUEST)
 
-            # Filter by stock status if `in_stock` is specified
-            in_stock = request.query_params.get('in_stock', "false") == 'true'
-            if in_stock:
-                products = products.filter(variants__in_stock__gt=0)
-
-            # Filter by discount if `has_discount` is specified
-            has_discount = request.query_params.get('has_discount', "false") == 'true'
-            if has_discount:
-                products = products.filter(variants__discount__gt=0)
+            # Filter by discount
+            has_discount = request.query_params.get('has_discount')
+            if has_discount is not None:
+                if has_discount.lower() == 'true':
+                    products = products.filter(variants__discount__gt=0)
+                elif has_discount.lower() != 'false':
+                    return Response({'detail': 'has_discount must be "true" or "false".'}, status=status.HTTP_400_BAD_REQUEST)
 
             # Search filter
-            search_query = request.query_params.get('search', None)
+            search_query = request.query_params.get('search')
             if search_query:
                 products = products.filter(Q(name__icontains=search_query) | Q(description__icontains=search_query))
 
             # Price filters
-            price_gte = request.query_params.get('price_gte', None)
-            price_lte = request.query_params.get('price_lte', None)
+            price_gte = request.query_params.get('price_gte')
+            price_lte = request.query_params.get('price_lte')
 
             products = products.annotate(min_price=Min('variants__price'), max_price=Max('variants__price'))
 
             if price_gte:
-                products = products.filter(max_price__gte=price_gte)
+                try:
+                    price_gte = float(price_gte)
+                    products = products.filter(max_price__gte=price_gte)
+                except ValueError:
+                    return Response({'detail': 'price_gte must be a number.'}, status=status.HTTP_400_BAD_REQUEST)
+
             if price_lte:
-                products = products.filter(min_price__lte=price_lte)
+                try:
+                    price_lte = float(price_lte)
+                    products = products.filter(min_price__lte=price_lte)
+                except ValueError:
+                    return Response({'detail': 'price_lte must be a number.'}, status=status.HTTP_400_BAD_REQUEST)
+
             # Sorting
-            sort_by = request.query_params.get('sort', None)
+            sort_by = request.query_params.get('sort')
             if sort_by in ['name', '-name', 'created_at', '-created_at']:
                 products = products.order_by(sort_by)
             else:
@@ -216,7 +229,10 @@ class AllProductsView(APIView):
             # Pagination
             paginator = self.pagination_class()
             paginated_products = paginator.paginate_queryset(products, request)
-            serializer = self.serializer_class(paginated_products, many=True, context={'request': request, 'view_type': 'list'})
+            serializer = self.serializer_class(
+                paginated_products, many=True,
+                context={'request': request, 'view_type': 'list'}
+            )
             return paginator.get_paginated_response(serializer.data)
 
         except MainCategoryModel.DoesNotExist: