diff --git a/CHANGELOG.md b/CHANGELOG.md
index 70eb1dec33..d7583d42a6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -148,6 +148,10 @@ and this project adheres to
 
 ### Fixed
 
+- The workflows REST API now returns a 422 validation error instead of a 500
+  when a create request omits `edges`, `jobs`, or `triggers` from the body
+  rather than sending them as empty lists.
+  [#4982](https://github.com/OpenFn/lightning/issues/4982)
 - The workflow version dropdown stayed empty after creating and saving a new
   workflow, until the page was refreshed.
   [#4973](https://github.com/OpenFn/lightning/issues/4973)
diff --git a/lib/lightning_web/controllers/api/workflows_controller.ex b/lib/lightning_web/controllers/api/workflows_controller.ex
index a005741ff2..d2df495f7d 100644
--- a/lib/lightning_web/controllers/api/workflows_controller.ex
+++ b/lib/lightning_web/controllers/api/workflows_controller.ex
@@ -413,6 +413,14 @@ defmodule LightningWeb.API.WorkflowsController do
        ),
        do: validate_workflow(edges, jobs, triggers, ids_map)
 
+  defp validate_workflow(%{} = params, ids_map) do
+    edges = Map.get(params, "edges", [])
+    jobs = Map.get(params, "jobs", [])
+    triggers = Map.get(params, "triggers", [])
+
+    validate_workflow(edges, jobs, triggers, ids_map)
+  end
+
   defp validate_workflow(edges, jobs, triggers, ids_map) do
     # {:ok, _ids} <- validate_ids(edges),
     with {:ok, triggers_ids} <- validate_ids(triggers),
diff --git a/test/lightning_web/controllers/api/workflows_controller_test.exs b/test/lightning_web/controllers/api/workflows_controller_test.exs
index 48aadfd1b6..fc4ee56287 100644
--- a/test/lightning_web/controllers/api/workflows_controller_test.exs
+++ b/test/lightning_web/controllers/api/workflows_controller_test.exs
@@ -782,6 +782,25 @@ defmodule LightningWeb.API.WorkflowsControllerTest do
              }
     end
 
+    test "returns 422 when edges, jobs and triggers are omitted", %{
+      conn: conn,
+      project: project
+    } do
+      conn =
+        post(
+          conn,
+          ~p"/api/projects/#{project.id}/workflows",
+          Jason.encode!(%{name: "workflow without children"})
+        )
+
+      assert json_response(conn, 422) == %{
+               "id" => nil,
+               "errors" => %{
+                 "edges" => ["Missing edge with source_trigger_id."]
+               }
+             }
+    end
+
     test "returns 422 when edges has multiple source triggers", %{
       conn: conn,
       project: project