diff --git a/AccountsIndex.sol b/AccountsIndex.sol
new file mode 100644
index 0000000..3eb943c
--- /dev/null
+++ b/AccountsIndex.sol
@@ -0,0 +1,12 @@
+pragma solidity >=0.6.12;
+
+// Author:	Louis Holbrook <dev@holbrook.no> 0826EDA1702D1E87C6E2875121D2E7BB88C2A746
+// SPDX-License-Identifier:	GPL-3.0-or-later
+// File-version: 3
+
+interface AccountsIndex {
+	function entryCount() external view returns (uint256);
+	function entry(uint256) external view returns (address);
+	function add(address _account) external returns (bool);
+	function have(address _account) external view returns (bool);
+}