diff --git a/src/interfaces/IModule.sol b/src/interfaces/IModule.sol
index bff19c6e..d6d4f148 100644
--- a/src/interfaces/IModule.sol
+++ b/src/interfaces/IModule.sol
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 /**
  * @title Module interface
  * @dev Interface for a module that can be added to SSO account (e.g. hook or validator).