diff --git a/mod/greeting.hpp b/mod/greeting.hpp
new file mode 100644
index 0000000..c9d1a3d
--- /dev/null
+++ b/mod/greeting.hpp
@@ -0,0 +1,9 @@
+#pragma once
+
+#include <string>
+
+namespace greeting {
+
+std::string make_greeting(std::string const& greetee);
+
+}