diff --git a/api.lua b/api.lua
index 4c07c86..8fa8c11 100644
--- a/api.lua
+++ b/api.lua
@@ -39,6 +39,10 @@ end
 -- @return nil if node doesn't exists or nodename with mode prefix
 -- @see https://github.com/Uberi/Minetest-WorldEdit
 function x_marketplace.normalize_nodename(nodename)
+	if not nodename then
+		return false
+	end
+
 	nodename = nodename:gsub("^%s*(.-)%s*$", "%1") -- strip spaces
 	if nodename == "" then return nil end