diff --git a/admyral/server/endpoints/workflow_endpoints.py b/admyral/server/endpoints/workflow_endpoints.py
index b36e0283..46756981 100644
--- a/admyral/server/endpoints/workflow_endpoints.py
+++ b/admyral/server/endpoints/workflow_endpoints.py
@@ -22,6 +22,7 @@
 
 
 MANUAL_TRIGGER_SOURCE_NAME = "manual"
+SPACE = " "
 
 
 class WorkflowBody(BaseModel):
@@ -61,6 +62,9 @@ async def push_workflow_impl(
     admyral_store = get_admyral_store()
     workers_client = get_workers_client()
 
+    if SPACE in workflow_name:
+        raise ValueError("Workflow name must not contain spaces.")
+
     if workflow_id:
         existing_workflow = await admyral_store.get_workflow_by_id(workflow_id)
     else:
diff --git a/web/src/components/save-workflow-button/save-workflow-button.tsx b/web/src/components/save-workflow-button/save-workflow-button.tsx
index 974074c5..7f4c0235 100644
--- a/web/src/components/save-workflow-button/save-workflow-button.tsx
+++ b/web/src/components/save-workflow-button/save-workflow-button.tsx
@@ -8,6 +8,8 @@ import { useEffect } from "react";
 import { errorToast, infoToast } from "@/lib/toast";
 import { AxiosError } from "axios";
 
+const SPACE = " ";
+
 export default function SaveWorkflowButton() {
 	const { getWorkflow, updateWebhookIdAndSecret } = useWorkflowStore();
 	const saveWorkflow = useSaveWorkflowApi();
@@ -41,13 +43,16 @@ export default function SaveWorkflowButton() {
 
 	const handleSaveWorkflow = () => {
 		const workflow = getWorkflow();
-		// TODO(frontend): validate workflow name
 		if (workflow.workflowName.length === 0) {
 			errorToast(
 				"Workflow name must not be empty. Go to settings to set one.",
 			);
 			return;
 		}
+		if (workflow.workflowName.includes(SPACE)) {
+			errorToast("Workflow name must contain empty spaces.");
+			return;
+		}
 		saveWorkflow.mutate(workflow);
 	};