diff --git a/gns3server/api/routes/compute/cloud_nodes.py b/gns3server/api/routes/compute/cloud_nodes.py
index 8453ba0d8..42e691235 100644
--- a/gns3server/api/routes/compute/cloud_nodes.py
+++ b/gns3server/api/routes/compute/cloud_nodes.py
@@ -184,6 +184,8 @@ async def update_cloud_nio(
     nio.filters.clear()
     if nio_data.filters:
         nio.filters = nio_data.filters
+    # NIO type is a Union (Ethernet/TAP/UDP); only UDPNIO carries markers.
+    nio.markers = getattr(nio_data, "markers", None) or {}
     await node.update_nio(port_number, nio)
     return nio.asdict()
 
diff --git a/gns3server/api/routes/compute/dynamips_nodes.py b/gns3server/api/routes/compute/dynamips_nodes.py
index 08eebb0d7..70d2b10c6 100644
--- a/gns3server/api/routes/compute/dynamips_nodes.py
+++ b/gns3server/api/routes/compute/dynamips_nodes.py
@@ -235,6 +235,7 @@ async def update_nio(
     nio.filters.clear()
     if nio_data.filters:
         nio.filters = nio_data.filters
+    nio.markers = nio_data.markers or {}
     await node.slot_update_nio_binding(adapter_number, port_number, nio)
     return nio.asdict()
 
diff --git a/gns3server/api/routes/compute/iou_nodes.py b/gns3server/api/routes/compute/iou_nodes.py
index 5be4fdd23..99544043d 100644
--- a/gns3server/api/routes/compute/iou_nodes.py
+++ b/gns3server/api/routes/compute/iou_nodes.py
@@ -254,6 +254,8 @@ async def update_iou_node_nio(
     nio.filters.clear()
     if nio_data.filters:
         nio.filters = nio_data.filters
+    # NIO type is a Union (Ethernet/TAP/UDP); only UDPNIO carries markers.
+    nio.markers = getattr(nio_data, "markers", None) or {}
     await node.adapter_update_nio_binding(adapter_number, port_number, nio)
     return nio.asdict()