diff --git a/script/input/5/integration.json b/script/input/5/integration.json
new file mode 100644
index 0000000..f0591a3
--- /dev/null
+++ b/script/input/5/integration.json
@@ -0,0 +1,23 @@
+{
+    "domains": {
+        "root": {
+            "rpc": "ETH_RPC_URL",
+            "chainlog": "0xdA0Ab1e0017DEbCd72Be8599041a2aa3bA7e740F"
+        },
+        "optimism": {
+            "rpc": "OPT_RPC_URL",
+            "l1Messenger": "0x5086d1eEF304eb5284A0f6720f79403b4e9bE294",
+            "l2Messenger": "0x4200000000000000000000000000000000000007"
+        },
+        "arbitrum": {
+            "rpc": "ARB_RPC_URL",
+            "inbox": "0x6BEbC4925716945D46F0Ec336D5C2564F419682C",
+            "arbSys": "0x0000000000000000000000000000000000000064"
+        },
+        "zkSync": {
+            "rpc": "ZKSYNC_RPC_URL",
+            "zkSyncMailbox": "0xcB3D5008e03Bf569dcdf17259Fa30726ED646931",
+            "l1MessengerContract": "0x0000000000000000000000000000000000008008"
+        }
+    }
+}
diff --git a/src/domains/ZKSyncDomain.sol b/src/domains/ZKSyncDomain.sol
new file mode 100644
index 0000000..e9c08a1
--- /dev/null
+++ b/src/domains/ZKSyncDomain.sol
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+// Copyright (C) 2022 Dai Foundation
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+pragma solidity >=0.8.0;
+
+import "forge-std/Vm.sol";
+
+import { Domain, BridgedDomain } from "./BridgedDomain.sol";
+
+contract ZKSyncDomain is BridgedDomain {
+
+    address public immutable zkSyncMailbox;
+    address public immutable l1MessengerContract;
+
+    bytes32 constant SENT_MESSAGE_TOPIC = keccak256("SentMessage(address,address,bytes,uint256,uint256)");
+
+    constructor(string memory _config, string memory _name, Domain _hostDomain) Domain(_config, _name) BridgedDomain(_hostDomain) {
+        zkSyncMailbox = MessengerLike(readConfigAddress("zkSyncMailbox"));
+        l1MessengerContract = MessengerLike(readConfigAddress("l1MessengerContract"));
+        vm.recordLogs();
+    }
+
+    function relayFromHost(bool switchToGuest) external override {
+        selectFork();
+        address malias;
+        unchecked {
+            malias = address(uint160(address(l1Messenger)) + OFFSET);
+        }
+
+        // Read all L1 -> L2 messages and relay them this fork
+        Vm.Log[] memory logs = vm.getRecordedLogs();
+        for (uint256 i = 0; i < logs.length; i++) {
+            Vm.Log memory log = logs[i];
+            if (log.topics[0] == SENT_MESSAGE_TOPIC) {
+                // TODO
+            }
+        }
+
+        if (!switchToGuest) {
+            hostDomain.selectFork();
+        }
+    }
+
+    function relayToHost(bool switchToHost) external override {
+        hostDomain.selectFork();
+
+        // Read all L2 -> L1 messages and relay them under host fork
+        Vm.Log[] memory logs = vm.getRecordedLogs();
+        for (uint256 i = 0; i < logs.length; i++) {
+            Vm.Log memory log = logs[i];
+            if (log.topics[0] == SENT_MESSAGE_TOPIC) {
+                // TODO
+            }
+        }
+
+        if (!switchToHost) {
+            selectFork();
+        }
+    }
+    
+}