diff --git a/bridges/evm/contracts/stdref/OptimisticStdReference.sol b/bridges/evm/contracts/stdref/OptimisticStdReference.sol
new file mode 100644
index 0000000000..335ff13dac
--- /dev/null
+++ b/bridges/evm/contracts/stdref/OptimisticStdReference.sol
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: Apache-2.0
+pragma solidity 0.6.11;
+pragma experimental ABIEncoderV2;
+
+import {Ownable} from "openzeppelin-solidity/contracts/access/Ownable.sol";
+import {StdReferenceBase} from "./IStdReference.sol";
+import {IBridge} from "../interfaces/IBridge.sol";
+import {Obi} from "../obi/Obi.sol";
+
+contract OptimisticStdReference {
+
+}
+
+// contract OptimisticStdReference is Ownable, StdReferenceBase {
+//     struct RefData {
+//         uint64 rate; // USD-rate, multiplied by 1e9.
+//         uint64 resolveTime; // UNIX epoch when data is resolved.
+//         uint64 requestId; // Request ID that contains this ref data.
+//         uint64 relayTime; // UNIX epoch when data is relayed to this contract.
+//     }
+
+//     mapping(string => RefData) public pending;
+//     mapping(string => RefData) public confirmed;
+
+//     function relay(
+//         string[] calldata _symbols,
+//         uint64[] calldata _rates,
+//         uint64[] calldata _resolveTimes,
+//         uint64[] calldata _requestIds
+//     ) external onlyOwner {
+//         uint256 len = _symbols.length;
+//         require(_rates.length == len, "BAD_RATES_LENGTH");
+//         require(_resolveTimes.length == len, "BAD_RESOLVE_TIMES_LENGTH");
+//         require(_requestIds.length == len, "BAD_REQUEST_IDS_LENGTH");
+//         for (uint256 idx = 0; idx < len; idx++) {
+//             _relay(
+//                 _symbols[idx],
+//                 _rates[idx],
+//                 _resolveTimes[idx],
+//                 _requestIds[idx]
+//             );
+//         }
+//     }
+
+//     function _relay(
+//         string memory _symbol,
+//         uint64 _rate,
+//         uint64 _resolveTime,
+//         uint64 _requestId
+//     ) internal {
+//         // RefData storage pendingRef = pending[_symbol];
+//         // confirmed[_symbol] = pending[_symbol];
+//     }
+
+//     function getReferenceData(string memory _base, string memory _quote)
+//         public
+//         override
+//         view
+//         returns (ReferenceData memory)
+//     {
+//         (uint256 baseRate, uint256 baseLastUpdate) = _getRefData(_base);
+//         (uint256 quoteRate, uint256 quoteLastUpdate) = _getRefData(_quote);
+//         return
+//             ReferenceData({
+//                 rate: (baseRate * 1e18) / quoteRate,
+//                 lastUpdatedBase: baseLastUpdate,
+//                 lastUpdatedQuote: quoteLastUpdate
+//             });
+//     }
+
+//     function _getRefData(string memory _symbol)
+//         internal
+//         view
+//         returns (uint256 rate, uint256 lastUpdate)
+//     {
+//         if (keccak256(bytes(_symbol)) == keccak256(bytes("USD"))) {
+//             return (1e9, now);
+//         }
+//         RefData storage refData = confirmed[_symbol];
+//         require(refData.resolveTime > 0, "REF_DATA_NOT_AVAILABLE");
+//         return (uint256(refData.rate), uint256(refData.resolveTime));
+//     }
+// }
diff --git a/bridges/evm/contracts/stdref/StdReferenceBasic.sol b/bridges/evm/contracts/stdref/StdReferenceBasic.sol
new file mode 100644
index 0000000000..bbe7de29bc
--- /dev/null
+++ b/bridges/evm/contracts/stdref/StdReferenceBasic.sol
@@ -0,0 +1,84 @@
+// SPDX-License-Identifier: Apache-2.0
+pragma solidity 0.6.11;
+pragma experimental ABIEncoderV2;
+
+import {AccessControl} from "openzeppelin-solidity/contracts/access/AccessControl.sol"; // prettier-ignore
+import {StdReferenceBase} from "./IStdReference.sol";
+
+contract StdReferenceBasic is AccessControl, StdReferenceBase {
+    event RefDataUpdate(
+        string symbol,
+        uint64 rate,
+        uint64 resolveTime,
+        uint64 requestId
+    );
+
+    struct RefData {
+        uint64 rate; // USD-rate, multiplied by 1e9.
+        uint64 resolveTime; // UNIX epoch when data is last resolved.
+        uint64 requestId; // BandChain request identifier for this data.
+    }
+
+    mapping(string => RefData) public refs; // Mapping from symbol to ref data.
+    bytes32 public constant RELAYER_ROLE = keccak256("RELAYER_ROLE");
+
+    constructor() public {
+        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);
+        _setupRole(RELAYER_ROLE, msg.sender);
+    }
+
+    function relay(
+        string[] memory _symbols,
+        uint64[] memory _rates,
+        uint64[] memory _resolveTimes,
+        uint64[] memory _requestIds
+    ) external {
+        require(hasRole(RELAYER_ROLE, msg.sender), "NOT_A_RELAYER");
+        uint256 len = _symbols.length;
+        require(_rates.length == len, "BAD_RATES_LENGTH");
+        require(_resolveTimes.length == len, "BAD_RESOLVE_TIMES_LENGTH");
+        require(_requestIds.length == len, "BAD_REQUEST_IDS_LENGTH");
+        for (uint256 idx = 0; idx < len; idx++) {
+            refs[_symbols[idx]] = RefData({
+                rate: _rates[idx],
+                resolveTime: _resolveTimes[idx],
+                requestId: _requestIds[idx]
+            });
+            emit RefDataUpdate(
+                _symbols[idx],
+                _rates[idx],
+                _resolveTimes[idx],
+                _requestIds[idx]
+            );
+        }
+    }
+
+    function getReferenceData(string memory _base, string memory _quote)
+        public
+        override
+        view
+        returns (ReferenceData memory)
+    {
+        (uint256 baseRate, uint256 baseLastUpdate) = _getRefData(_base);
+        (uint256 quoteRate, uint256 quoteLastUpdate) = _getRefData(_quote);
+        return
+            ReferenceData({
+                rate: (baseRate * 1e18) / quoteRate,
+                lastUpdatedBase: baseLastUpdate,
+                lastUpdatedQuote: quoteLastUpdate
+            });
+    }
+
+    function _getRefData(string memory _symbol)
+        internal
+        view
+        returns (uint256 rate, uint256 lastUpdate)
+    {
+        if (keccak256(bytes(_symbol)) == keccak256(bytes("USD"))) {
+            return (1e9, now);
+        }
+        RefData storage refData = refs[_symbol];
+        require(refData.resolveTime > 0, "REF_DATA_NOT_AVAILABLE");
+        return (uint256(refData.rate), uint256(refData.resolveTime));
+    }
+}