diff --git a/src/apps/api/serializers.py b/src/apps/api/serializers.py
index 023fbb8..4c7036e 100644
--- a/src/apps/api/serializers.py
+++ b/src/apps/api/serializers.py
@@ -5,6 +5,14 @@ from apps.lyric.models import User
 
 
 class ItemSerializer(serializers.ModelSerializer):
+    text = serializers.CharField()
+
+    def validate_text(self, value):
+        list_ = self.context["list"]
+        if list_.item_set.filter(text=value).exists():
+            raise serializers.ValidationError("duplicate")
+        return value
+
     class Meta:
         model = Item
         fields = ["id", "text"]
diff --git a/src/apps/api/tests/integrated/test_views.py b/src/apps/api/tests/integrated/test_views.py
index 9a6d2e6..76b30d9 100644
--- a/src/apps/api/tests/integrated/test_views.py
+++ b/src/apps/api/tests/integrated/test_views.py
@@ -24,7 +24,6 @@ class ListDetailAPITest(BaseAPITest):
         self.assertEqual(len(response.data["items"]), 2)
 
 class ListItemsAPITest(BaseAPITest):
-
     def test_can_add_item_to_list(self):
         list_ = List.objects.create(owner=self.user)
 
@@ -37,6 +36,28 @@ class ListItemsAPITest(BaseAPITest):
         self.assertEqual(Item.objects.count(), 1)
         self.assertEqual(Item.objects.first().text, "a new item")
 
+    def test_cannot_add_empty_item_to_list(self):
+        list_ = List.objects.create(owner=self.user)
+
+        response = self.client.post(
+            f"/api/lists/{list_.id}/items/",
+            {"text": ""},
+        )
+
+        self.assertEqual(response.status_code, 400)
+        self.assertEqual(Item.objects.count(), 0)
+
+    def test_cannot_add_duplicate_item_to_list(self):
+        list_ = List.objects.create(owner=self.user)
+        Item.objects.create(text="list item", list=list_)
+        duplicate_response = self.client.post(
+            f"/api/lists/{list_.id}/items/",
+            {"text": "list item"},
+        )
+
+        self.assertEqual(duplicate_response.status_code, 400)
+        self.assertEqual(Item.objects.count(), 1)
+
 class ListsAPITest(BaseAPITest):
     def test_get_returns_only_users_lists(self):
         list1 = List.objects.create(owner=self.user)
diff --git a/src/apps/api/views.py b/src/apps/api/views.py
index ee0defa..95d7ff8 100644
--- a/src/apps/api/views.py
+++ b/src/apps/api/views.py
@@ -16,7 +16,7 @@ class ListDetailAPI(APIView):
 class ListItemsAPI(APIView):
     def post(self, request, list_id):
         list_ = get_object_or_404(List, id=list_id)
-        serializer = ItemSerializer(data=request.data)
+        serializer = ItemSerializer(data=request.data, context={"list": list_})
         if serializer.is_valid():
             serializer.save(list=list_)
             return Response(serializer.data, status=201)