diff --git a/source/batch-call/contracts/BatchCall.sol b/source/batch-call/contracts/BatchCall.sol
index cbae54b37..400940589 100644
--- a/source/batch-call/contracts/BatchCall.sol
+++ b/source/batch-call/contracts/BatchCall.sol
@@ -54,12 +54,15 @@ contract BatchCall {
     require(tokenAddresses.length > 0);
     uint256[] memory balances = new uint256[](tokenAddresses.length);
 
-    for (uint256 i; i < tokenAddresses.length; ++i) {
+    for (uint256 i; i < tokenAddresses.length; ) {
       if (tokenAddresses[i] != address(0x0)) {
         balances[i] = tokenBalance(userAddress, tokenAddresses[i]);
       } else {
         balances[i] = userAddress.balance;
       }
+      unchecked {
+        ++i;
+      }
     }
     return balances;
   }
@@ -79,8 +82,8 @@ contract BatchCall {
     uint256[] memory balances = new uint256[](
       tokenAddresses.length * userAddresses.length
     );
-    for (uint256 i; i < userAddresses.length; ++i) {
-      for (uint256 j; j < tokenAddresses.length; ++j) {
+    for (uint256 i; i < userAddresses.length; ) {
+      for (uint256 j; j < tokenAddresses.length; ) {
         if (tokenAddresses[j] != address(0x0)) {
           // ETH address in Etherdelta config
           balances[(i * tokenAddresses.length) + j] = tokenBalance(
@@ -90,6 +93,12 @@ contract BatchCall {
         } else {
           balances[(i * tokenAddresses.length) + j] = userAddresses[i].balance;
         }
+        unchecked {
+          ++j;
+        }
+      }
+      unchecked {
+        ++i;
       }
     }
     return balances;
@@ -143,12 +152,15 @@ contract BatchCall {
     require(tokenAddresses.length > 0);
     uint256[] memory allowances = new uint256[](tokenAddresses.length);
 
-    for (uint256 i; i < tokenAddresses.length; ++i) {
+    for (uint256 i; i < tokenAddresses.length; ) {
       allowances[i] = tokenAllowance(
         userAddress,
         spenderAddress,
         tokenAddresses[i]
       );
+      unchecked {
+        ++i;
+      }
     }
     return allowances;
   }
@@ -171,13 +183,19 @@ contract BatchCall {
       tokenAddresses.length * userAddresses.length
     );
 
-    for (uint256 i; i < userAddresses.length; ++i) {
-      for (uint256 j; j < tokenAddresses.length; ++j) {
+    for (uint256 i; i < userAddresses.length; ) {
+      for (uint256 j; j < tokenAddresses.length; ) {
         allowances[(i * tokenAddresses.length) + j] = tokenAllowance(
           userAddresses[i],
           spenderAddress,
           tokenAddresses[j]
         );
+        unchecked {
+          ++j;
+        }
+      }
+      unchecked {
+        ++i;
       }
     }
     return allowances;
@@ -198,9 +216,12 @@ contract BatchCall {
     require(orders.length > 0);
     bool[] memory orderValidity = new bool[](orders.length);
 
-    for (uint256 i; i < orders.length; ++i) {
+    for (uint256 i; i < orders.length; ) {
       (, uint256 errorCount) = swapContract.check(senderWallet, orders[i]);
       orderValidity[i] = errorCount == 0 ? true : false;
+      unchecked {
+        ++i;
+      }
     }
     return orderValidity;
   }
@@ -220,7 +241,7 @@ contract BatchCall {
     require(orders.length > 0);
     bool[] memory orderValidity = new bool[](orders.length);
 
-    for (uint256 i; i < orders.length; ++i) {
+    for (uint256 i; i < orders.length; ) {
       ISwapERC20.OrderERC20 memory order = orders[i];
       (uint256 errorCount, ) = swapERC20Contract.check(
         senderWallet,
@@ -236,6 +257,9 @@ contract BatchCall {
         order.s
       );
       orderValidity[i] = errorCount == 0 ? true : false;
+      unchecked {
+        ++i;
+      }
     }
     return orderValidity;
   }
@@ -257,8 +281,11 @@ contract BatchCall {
     require(signerWallets.length == nonces.length);
     bool[] memory nonceUsed = new bool[](signerWallets.length);
 
-    for (uint256 i; i < signerWallets.length; ++i) {
+    for (uint256 i; i < signerWallets.length; ) {
       nonceUsed[i] = swapContract.nonceUsed(signerWallets[i], nonces[i]);
+      unchecked {
+        ++i;
+      }
     }
     return nonceUsed;
   }
diff --git a/source/registry/contracts/Registry.sol b/source/registry/contracts/Registry.sol
index 1ce3ce8f8..d2bcd82f6 100644
--- a/source/registry/contracts/Registry.sol
+++ b/source/registry/contracts/Registry.sol
@@ -89,7 +89,9 @@ contract Registry {
     bytes4[] memory _protocolList = new bytes4[](_protocolListLength);
 
     for (uint256 i = _protocolListLength; i > 0; ) {
-      i--;
+      unchecked {
+        --i;
+      }
       bytes4 _protocol = bytes4(supportedProtocolList.at(i));
       _protocolList[i] = _protocol;
       supportedProtocolList.remove(_protocol);
@@ -103,7 +105,9 @@ contract Registry {
     address[] memory _tokenList = new address[](_tokenListLength);
 
     for (uint256 i = _tokenListLength; i > 0; ) {
-      i--;
+      unchecked {
+        --i;
+      }
       address _token = supportedTokenList.at(i);
       _tokenList[i] = _token;
       supportedTokenList.remove(_token);
@@ -135,10 +139,13 @@ contract Registry {
       msg.sender
     ];
 
-    for (uint256 i; i < _length; ++i) {
+    for (uint256 i; i < _length; ) {
       bytes4 protocol = _protocols[i];
       if (!_protocolList.add(protocol)) revert ProtocolExists(protocol);
       stakersByProtocol[protocol].add(msg.sender);
+      unchecked {
+        ++i;
+      }
     }
 
     uint256 _transferAmount = supportCost * _length;
@@ -159,11 +166,14 @@ contract Registry {
     EnumerableSet.Bytes32Set storage protocolList = protocolsByStaker[
       msg.sender
     ];
-    for (uint256 i; i < _length; ++i) {
+    for (uint256 i; i < _length; ) {
       bytes4 _protocol = _protocols[i];
       if (!protocolList.remove(_protocol))
         revert ProtocolDoesNotExist(_protocol);
       stakersByProtocol[_protocol].remove(msg.sender);
+      unchecked {
+        ++i;
+      }
     }
 
     uint256 _transferAmount = supportCost * _length;
@@ -185,8 +195,11 @@ contract Registry {
     EnumerableSet.AddressSet storage stakers = stakersByProtocol[_protocol];
     uint256 _length = stakers.length();
     _urls = new string[](_length);
-    for (uint256 i; i < _length; ++i) {
+    for (uint256 i; i < _length; ) {
       _urls[i] = stakerServerURLs[address(stakers.at(i))];
+      unchecked {
+        ++i;
+      }
     }
   }
 
@@ -214,8 +227,11 @@ contract Registry {
     EnumerableSet.Bytes32Set storage _protocols = protocolsByStaker[_staker];
     uint256 _length = _protocols.length();
     _protocolList = new bytes4[](_length);
-    for (uint256 i; i < _length; ++i) {
+    for (uint256 i; i < _length; ) {
       _protocolList[i] = bytes4(_protocols.at(i));
+      unchecked {
+        ++i;
+      }
     }
   }
 
@@ -230,8 +246,11 @@ contract Registry {
     EnumerableSet.AddressSet storage _stakerList = stakersByProtocol[_protocol];
     uint256 _length = _stakerList.length();
     _stakers = new address[](_length);
-    for (uint256 i; i < _length; ++i) {
+    for (uint256 i; i < _length; ) {
       _stakers[i] = _stakerList.at(i);
+      unchecked {
+        ++i;
+      }
     }
   }
 
@@ -244,10 +263,13 @@ contract Registry {
     if (_length <= 0) revert ArgumentInvalid();
     EnumerableSet.AddressSet storage tokenList = tokensByStaker[msg.sender];
 
-    for (uint256 i; i < _length; ++i) {
+    for (uint256 i; i < _length; ) {
       address _token = _tokens[i];
       if (!tokenList.add(_token)) revert TokenExists(_token);
       stakersByToken[_token].add(msg.sender);
+      unchecked {
+        ++i;
+      }
     }
     uint256 _transferAmount = supportCost * _length;
     emit AddTokens(msg.sender, _tokens);
@@ -264,10 +286,13 @@ contract Registry {
     uint256 _length = _tokens.length;
     if (_length <= 0) revert ArgumentInvalid();
     EnumerableSet.AddressSet storage tokenList = tokensByStaker[msg.sender];
-    for (uint256 i; i < _length; ++i) {
+    for (uint256 i; i < _length; ) {
       address token = _tokens[i];
       if (!tokenList.remove(token)) revert TokenDoesNotExist(token);
       stakersByToken[token].remove(msg.sender);
+      unchecked {
+        ++i;
+      }
     }
     uint256 _transferAmount = supportCost * _length;
     emit RemoveTokens(msg.sender, _tokens);
@@ -287,8 +312,11 @@ contract Registry {
     EnumerableSet.AddressSet storage stakers = stakersByToken[_token];
     uint256 _length = stakers.length();
     urls = new string[](_length);
-    for (uint256 i; i < _length; ++i) {
+    for (uint256 i; i < _length; ) {
       urls[i] = stakerServerURLs[address(stakers.at(i))];
+      unchecked {
+        ++i;
+      }
     }
   }
 
@@ -316,8 +344,11 @@ contract Registry {
     EnumerableSet.AddressSet storage tokens = tokensByStaker[_staker];
     uint256 _length = tokens.length();
     tokenList = new address[](_length);
-    for (uint256 i; i < _length; ++i) {
+    for (uint256 i; i < _length; ) {
       tokenList[i] = tokens.at(i);
+      unchecked {
+        ++i;
+      }
     }
   }
 
@@ -332,8 +363,11 @@ contract Registry {
     EnumerableSet.AddressSet storage stakerList = stakersByToken[_token];
     uint256 _length = stakerList.length();
     _stakers = new address[](_length);
-    for (uint256 i; i < _length; ++i) {
+    for (uint256 i; i < _length; ) {
       _stakers[i] = stakerList.at(i);
+      unchecked {
+        ++i;
+      }
     }
   }
 
@@ -347,8 +381,11 @@ contract Registry {
   ) external view returns (string[] memory _urls) {
     uint256 stakersLength = _stakers.length;
     _urls = new string[](stakersLength);
-    for (uint256 i; i < stakersLength; ++i) {
+    for (uint256 i; i < stakersLength; ) {
       _urls[i] = stakerServerURLs[_stakers[i]];
+      unchecked {
+        ++i;
+      }
     }
   }
 
diff --git a/source/staking/contracts/Staking.sol b/source/staking/contracts/Staking.sol
index 51ba12ec2..9a98f8486 100644
--- a/source/staking/contracts/Staking.sol
+++ b/source/staking/contracts/Staking.sol
@@ -21,7 +21,7 @@ contract Staking is IStaking, Ownable {
   uint256 public stakingDuration;
 
   // Minimum delay to staking duration change
-  uint256 private minDurationChangeDelay;
+  uint256 private immutable minDurationChangeDelay;
 
   // Timestamp after which staking duration change is possible
   uint256 private activeDurationChangeTimestamp;
@@ -181,7 +181,7 @@ contract Staking is IStaking, Ownable {
    */
   function getStakes(
     address _account
-  ) external view override returns (Stake memory _accountStake) {
+  ) external view override returns (Stake memory) {
     return stakes[_account];
   }
 
diff --git a/source/swap-erc20/contracts/SwapERC20.sol b/source/swap-erc20/contracts/SwapERC20.sol
index 6d20512b9..0d57bec48 100644
--- a/source/swap-erc20/contracts/SwapERC20.sol
+++ b/source/swap-erc20/contracts/SwapERC20.sol
@@ -390,11 +390,14 @@ contract SwapERC20 is ISwapERC20, Ownable, EIP712 {
    * @param nonces uint256[] List of nonces to cancel
    */
   function cancel(uint256[] calldata nonces) external override {
-    for (uint256 i; i < nonces.length; ++i) {
+    for (uint256 i; i < nonces.length; ) {
       uint256 nonce = nonces[i];
       if (_markNonceAsUsed(msg.sender, nonce)) {
         emit Cancel(nonce, msg.sender);
       }
+      unchecked {
+        ++i;
+      }
     }
   }
 
diff --git a/source/swap-erc20/contracts/interfaces/INoReturnERC20.sol b/source/swap-erc20/contracts/interfaces/INoReturnERC20.sol
index 798013daa..b57329fc7 100644
--- a/source/swap-erc20/contracts/interfaces/INoReturnERC20.sol
+++ b/source/swap-erc20/contracts/interfaces/INoReturnERC20.sol
@@ -2,5 +2,5 @@
 pragma solidity 0.8.23;
 
 interface INoReturnERC20 {
-  function transferFrom(address from, address to, uint value) external;
+  function transferFrom(address from, address to, uint256 value) external;
 }
diff --git a/source/swap/contracts/Swap.sol b/source/swap/contracts/Swap.sol
index 929e52381..4e4f81d63 100644
--- a/source/swap/contracts/Swap.sol
+++ b/source/swap/contracts/Swap.sol
@@ -48,7 +48,7 @@ contract Swap is ISwap, Ownable2Step, EIP712 {
 
   uint256 public protocolFee;
   address public protocolFeeWallet;
-  bytes4 public requiredSenderKind;
+  bytes4 public immutable requiredSenderKind;
 
   // Mapping of ERC165 interface ID to token adapter
   mapping(bytes4 => IAdapter) public adapters;
@@ -73,8 +73,12 @@ contract Swap is ISwap, Ownable2Step, EIP712 {
     DOMAIN_CHAIN_ID = block.chainid;
     DOMAIN_SEPARATOR = _domainSeparatorV4();
 
-    for (uint256 i; i < _adapters.length; ++i) {
+    uint256 adaptersLength = _adapters.length;
+    for (uint256 i; i < adaptersLength; ) {
       adapters[_adapters[i].interfaceId()] = _adapters[i];
+      unchecked {
+        ++i;
+      }
     }
     requiredSenderKind = _requiredSenderKind;
     protocolFee = _protocolFee;
@@ -230,10 +234,13 @@ contract Swap is ISwap, Ownable2Step, EIP712 {
    * @param nonces uint256[] List of nonces to cancel
    */
   function cancel(uint256[] calldata nonces) external override {
-    for (uint256 i; i < nonces.length; ++i) {
+    for (uint256 i; i < nonces.length; ) {
       uint256 nonce = nonces[i];
       _markNonceAsUsed(msg.sender, nonce);
       emit Cancel(nonce, msg.sender);
+      unchecked {
+        ++i;
+      }
     }
   }