diff --git a/contracts/common/interfaces.sol b/contracts/common/interfaces.sol
index e633a8e..9539ad0 100644
--- a/contracts/common/interfaces.sol
+++ b/contracts/common/interfaces.sol
@@ -1,5 +1,14 @@
 pragma solidity ^0.6.0;
 
+interface TokenInterface {
+    function approve(address, uint) external;
+    function transfer(address, uint) external;
+    function transferFrom(address, address, uint) external;
+    function deposit() external payable;
+    function withdraw(uint) external;
+    function balanceOf(address) external view returns (uint);
+}
+
 interface MemoryInterface {
     function getUint(uint id) external returns (uint num);
     function setUint(uint id, uint val) external;
@@ -7,4 +16,5 @@ interface MemoryInterface {
 
 interface EventInterface {
     function emitEvent(uint connectorType, uint connectorID, bytes32 eventCode, bytes calldata eventData) external;
-}
\ No newline at end of file
+}
+