diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4179538e22..8bde64c26a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -36,6 +36,9 @@ and this project adheres to
 
 ### Fixed
 
+- Collections controller sending an invalid response body when a item doesn't
+  exist [#2733](https://github.com/OpenFn/lightning/issues/2733)
+
 ## [v2.10.4] - 2024-11-22
 
 ### Added
diff --git a/lib/lightning_web/controllers/collections_controller.ex b/lib/lightning_web/controllers/collections_controller.ex
index e528864434..4cf12dce47 100644
--- a/lib/lightning_web/controllers/collections_controller.ex
+++ b/lib/lightning_web/controllers/collections_controller.ex
@@ -59,9 +59,7 @@ defmodule LightningWeb.CollectionsController do
          :ok <- authorize(conn, collection) do
       case Collections.get(collection, key) do
         nil ->
-          conn
-          |> put_status(:no_content)
-          |> json(nil)
+          resp(conn, :no_content, "")
 
         item ->
           json(conn, item)
diff --git a/test/lightning_web/collections_controller_test.exs b/test/lightning_web/collections_controller_test.exs
index fc21a28bd1..0307797271 100644
--- a/test/lightning_web/collections_controller_test.exs
+++ b/test/lightning_web/collections_controller_test.exs
@@ -131,7 +131,7 @@ defmodule LightningWeb.API.CollectionsControllerTest do
         |> assign_bearer(token)
         |> get(~p"/collections/#{collection.name}/some-unexisting-key")
 
-      assert json_response(conn, 204) == nil
+      assert response(conn, 204) == ""
     end
   end