diff --git a/script/Deploy.sol b/script/Deploy.sol
index 35f3495..d3014ae 100644
--- a/script/Deploy.sol
+++ b/script/Deploy.sol
@@ -5,6 +5,7 @@ import "forge-std/Script.sol";
 import "forge-std/console2.sol";
 import "../src/QueryHelper.sol";
 import "../src/Factory.sol";
+import "../src/Dexorder.sol";
 import "../test/MockEnv.sol";
 
 contract Deploy is Script {
@@ -13,12 +14,15 @@ contract Deploy is Script {
         vm.startBroadcast(deployerPrivateKey);
         Factory deployer = new Factory{salt:keccak256(abi.encode(1))}();
         QueryHelper query = new QueryHelper();
+        Dexorder dexorder = new Dexorder();
         MockEnv mock = new MockEnv();
         vm.stopBroadcast();
         console2.log('VaultDeployer');
         console2.log(address(deployer));
         console2.log('QueryHelper');
         console2.log(address(query));
+        console2.log('Dexorder');
+        console2.log(address(dexorder));
         console2.log('MockEnv'); // todo no mock in production deployment
         console2.log(address(mock));
     }
diff --git a/src/Constants.sol b/src/Constants.sol
index 2de4a06..2af5841 100644
--- a/src/Constants.sol
+++ b/src/Constants.sol
@@ -17,6 +17,6 @@ library Constants {
 
 
     // Swap statuses
-    string internal constant SWAP_OK = ''; // fastest comparison
+    bytes32 internal constant SWAP_OK = ''; // fastest comparison
     // other errors may be passed through from Uniswap
 }
diff --git a/src/Dexorder.sol b/src/Dexorder.sol
new file mode 100644
index 0000000..ec32236
--- /dev/null
+++ b/src/Dexorder.sol
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity =0.7.6;
+import "./OrderLib.sol";
+import "./Vault.sol";
+pragma abicoder v2;
+
+contract Dexorder {
+    // represents the Dexorder organization
+
+    event DexorderExecutions(uint128 indexed id, bytes[] errors);
+
+    struct ExecutionRequest {
+        address payable vault;
+        uint64 orderIndex;
+        uint8 trancheIndex;
+        OrderLib.PriceProof proof;
+    }
+
+
+    function execute( uint128 id, ExecutionRequest memory req ) public returns (bytes memory error) {
+        error = _execute(req);
+        bytes[] memory errors = new bytes[](1);
+        errors[0] = error;
+        emit DexorderExecutions(id, errors);
+    }
+
+
+    function execute( uint128 id, ExecutionRequest[] memory reqs ) public returns (bytes[] memory errors) {
+        errors = new bytes[](reqs.length);
+        for( uint8 i=0; i<reqs.length; i++ )
+            errors[i] = _execute(reqs[i]);
+        emit DexorderExecutions(id, errors);
+    }
+
+
+    function _execute( ExecutionRequest memory req ) private returns (bytes memory error) {
+        // single tranche execution
+        try Vault(req.vault).execute(req.orderIndex, req.trancheIndex, req.proof) {
+            return '';
+        }
+        catch (bytes memory reason) {
+            return reason;
+        }
+    }
+}
diff --git a/src/OrderLib.sol b/src/OrderLib.sol
index 34c483b..f3ca8e2 100644
--- a/src/OrderLib.sol
+++ b/src/OrderLib.sol
@@ -131,19 +131,15 @@ library OrderLib {
     }
 
     function _placeOrder(OrdersInfo storage self, SwapOrder memory order) internal {
-        console2.log('OrderLib._placeOrder()');
         SwapOrder[] memory orders = new SwapOrder[](1);
         orders[0] = order;
         return _placeOrders(self,orders,OcoMode.NO_OCO);
     }
 
     function _placeOrders(OrdersInfo storage self, SwapOrder[] memory orders, OcoMode ocoMode) internal {
-        console2.log('_placeOrders A');
         require(orders.length < type(uint8).max);
-        console2.log('_placeOrders B');
         uint64 startIndex = uint64(self.orders.length);
         require(startIndex < type(uint64).max);
-        console2.log('_placeOrders C');
         uint64 ocoGroup;
         if( ocoMode == OcoMode.NO_OCO )
             ocoGroup = NO_OCO_INDEX;
@@ -153,11 +149,9 @@ library OrderLib {
         }
         else
             revert('OCOM');
-        console2.log('_placeOrders D');
         for( uint8 o = 0; o < orders.length; o++ ) {
             SwapOrder memory order = orders[o];
             require(order.route.exchange == Exchange.UniswapV3, 'UR');
-            console2.log('_placeOrders E');
             // todo more order validation
             // we must explicitly copy into storage because Solidity doesn't implement copying the double-nested
             // tranches constraints array :(
@@ -171,7 +165,6 @@ library OrderLib {
             status.order.route = order.route;
             status.order.chainOrder = order.chainOrder;
             status.order.outputDirectlyToOwner = order.outputDirectlyToOwner;
-            console2.log('_placeOrders F');
             for( uint t=0; t<order.tranches.length; t++ ) {
                 status.order.tranches.push();
                 OrderLib.Tranche memory ot = order.tranches[t]; // order tranche
@@ -179,22 +172,18 @@ library OrderLib {
                 st.fraction = ot.fraction;
                 for( uint c=0; c<ot.constraints.length; c++ )
                     st.constraints.push(ot.constraints[c]);
-                console2.log('_placeOrders G');
                 status.trancheFilledIn.push(0);
                 status.trancheFilledOut.push(0);
             }
             status.state = SwapOrderState.Open;
             status.start = uint32(block.timestamp);
             status.ocoGroup = ocoGroup;
-            console2.log('_placeOrders H');
         }
         emit DexorderSwapPlaced(startIndex,uint8(orders.length));
     }
 
 
-    // return codes:
-    //
-    // returns the zero-length string '' on success
+    // revert codes:
     //
     // NO order is not open
     // OCO order was implicitly canceled by an OCO
@@ -202,12 +191,10 @@ library OrderLib {
     // TE current time is too early for this tranche
     // TL current time is too late for this tranche
     //
-    function execute(OrdersInfo storage self, uint64 orderIndex, uint8 tranche_index, PriceProof memory proof) internal
-    returns (string memory error)
-    {
+    function execute(OrdersInfo storage self, address owner, uint64 orderIndex, uint8 tranche_index, PriceProof memory proof) internal {
         SwapOrderStatus storage status = self.orders[orderIndex];
         if (status.state != SwapOrderState.Open)
-            return 'NO'; // Not Open
+            revert('NO'); // Not Open
         Tranche storage tranche = status.order.tranches[tranche_index];
         uint160 sqrtPriceX96 = 0;
         uint160 sqrtPriceLimitX96 = 0;
@@ -219,10 +206,10 @@ library OrderLib {
                 TimeConstraint memory tc = abi.decode(constraint.constraint, (TimeConstraint));
                 uint32 time = tc.earliest.mode == TimeMode.Timestamp ? tc.earliest.time : status.start + tc.earliest.time;
                 if (time > block.timestamp)
-                    return 'TE'; // time early
+                    revert('TE'); // time early
                 time = tc.latest.mode == TimeMode.Timestamp ? tc.latest.time : status.start + tc.latest.time;
                 if (time < block.timestamp)
-                    return 'TL'; // time late
+                    revert('TL'); // time late
             }
             else if (constraint.mode == ConstraintMode.Limit) {
                 if( sqrtPriceX96 == 0 ) {
@@ -233,20 +220,19 @@ library OrderLib {
                 if( pc.isRatio )
                     pc.valueSqrtX96 = uint160(price * pc.valueSqrtX96 / 2**96); // todo overflow check!
                 if( pc.isAbove && price < pc.valueSqrtX96 || !pc.isAbove && price > pc.valueSqrtX96 )
-                    return 'L';
+                    revert('L');
             }
             else if (constraint.mode == ConstraintMode.Barrier) {
-                return 'NI'; // not implemented
+                revert('NI'); // not implemented
             }
             else if (constraint.mode == ConstraintMode.Trailing) {
-                return 'NI'; // not implemented
+                revert('NI'); // not implemented
             }
             else if (constraint.mode == ConstraintMode.Line) {
-                return 'NI'; // not implemented
+                revert('NI'); // not implemented
             }
-            else
-                return 'NI'; // not implemented
-            // unknown constraint
+            else // unknown constraint
+                revert('NI'); // not implemented
         }
         uint256 amount = status.order.amount * tranche.fraction / type(uint16).max // the most this tranche could do
                          - (status.order.amountIsInput ? status.trancheFilledIn[tranche_index] : status.trancheFilledOut[tranche_index]); // minus tranche fills
@@ -254,42 +240,39 @@ library OrderLib {
         uint256 remaining = status.order.amount - (status.order.amountIsInput ? status.filledIn : status.filledOut);
         if (amount > remaining)  // not more than the order's overall remaining amount
             amount = remaining;
+        address recipient = status.order.outputDirectlyToOwner ? owner : address(this);
         uint256 amountIn;
         uint256 amountOut;
         if( status.order.route.exchange == Exchange.UniswapV3 )
-            (error, amountIn, amountOut) = _do_execute_univ3(status.order, pool, amount, sqrtPriceLimitX96);
+            (amountIn, amountOut) = _do_execute_univ3(recipient, status.order, pool, amount, sqrtPriceLimitX96);
         //  todo other routes
         else
-            return 'UR'; // unknown route
-        if( bytes(error).length == 0 ) {
-            status.filledIn += amountIn;
-            status.filledOut += amountOut;
-            status.trancheFilledIn[tranche_index] += amountIn;
-            status.trancheFilledOut[tranche_index] += amountOut;
-            emit DexorderSwapFilled(orderIndex, tranche_index, amountIn, amountOut);
-            _checkCompleted(self, orderIndex, status);
-        }
-        return ''; // success is no error, said no one
+            revert('UR'); // unknown route
+        status.filledIn += amountIn;
+        status.filledOut += amountOut;
+        status.trancheFilledIn[tranche_index] += amountIn;
+        status.trancheFilledOut[tranche_index] += amountOut;
+        emit DexorderSwapFilled(orderIndex, tranche_index, amountIn, amountOut);
+        _checkCompleted(self, orderIndex, status);
     }
 
 
-    function _do_execute_univ3( SwapOrder storage order, address pool, uint256 amount, uint160 sqrtPriceLimitX96) private
-    returns (string memory error, uint256 amountIn, uint256 amountOut)
+    function _do_execute_univ3( address recipient, SwapOrder storage order, address pool, uint256 amount, uint160 sqrtPriceLimitX96) private
+    returns (uint256 amountIn, uint256 amountOut)
     {
         // todo refactor this signature to be more low-level, taking only the in/out amounts and limit prices.  doesnt need self/status/index
         if (sqrtPriceLimitX96 == 0)
         // check pool inversion to see if the price should be high or low
             sqrtPriceLimitX96 = order.tokenIn < order.tokenOut ? 0 : type(uint160).max;
-        // todo swap direct to owner
         if (order.amountIsInput) {
             amountIn = amount;
-            (error, amountOut) = UniswapSwapper.swapExactInput(UniswapSwapper.SwapParams(
-                    pool, order.tokenIn, order.tokenOut, order.route.fee, amount, sqrtPriceLimitX96));
+            amountOut = UniswapSwapper.swapExactInput(UniswapSwapper.SwapParams(
+                    pool, order.tokenIn, order.tokenOut, recipient, order.route.fee, amount, sqrtPriceLimitX96));
         }
         else {
             amountOut = amount;
-            (error, amountIn) = UniswapSwapper.swapExactOutput(UniswapSwapper.SwapParams(
-                    pool, order.tokenIn, order.tokenOut, order.route.fee, amount, sqrtPriceLimitX96));
+            amountIn = UniswapSwapper.swapExactOutput(UniswapSwapper.SwapParams(
+                    pool, order.tokenIn, order.tokenOut, recipient, order.route.fee, amount, sqrtPriceLimitX96));
         }
     }
 
diff --git a/src/UniswapSwapper.sol b/src/UniswapSwapper.sol
index 37acf3a..934c407 100644
--- a/src/UniswapSwapper.sol
+++ b/src/UniswapSwapper.sol
@@ -12,12 +12,13 @@ library UniswapSwapper {
         address pool;
         address tokenIn;
         address tokenOut;
+        address recipient;
         uint24 fee;
         uint256 amount;
         uint160 sqrtPriceLimitX96;
     }
 
-    function swapExactInput(SwapParams memory params) internal returns (string memory error, uint256 amountOut)
+    function swapExactInput(SwapParams memory params) internal returns (uint256 amountOut)
     {
         //     struct ExactInputSingleParams {
         //        address tokenIn;
@@ -29,22 +30,13 @@ library UniswapSwapper {
         //        uint256 amountOutMinimum;
         //        uint160 sqrtPriceLimitX96;
         //    }
-
-        try Constants.uniswapV3SwapRouter.exactInputSingle(ISwapRouter.ExactInputSingleParams({
-            tokenIn: params.tokenIn, tokenOut: params.tokenOut, fee: params.fee, recipient: address(this), // todo return directly to wallet?
+        return Constants.uniswapV3SwapRouter.exactInputSingle(ISwapRouter.ExactInputSingleParams({
+            tokenIn: params.tokenIn, tokenOut: params.tokenOut, fee: params.fee, recipient: params.recipient,
             deadline: block.timestamp, amountIn: params.amount, amountOutMinimum: 0, sqrtPriceLimitX96: params.sqrtPriceLimitX96
-        })) returns (uint256 filledOut) {
-            amountOut = filledOut;
-            error = Constants.SWAP_OK;
-        }
-        catch Error(string memory reason) {
-            amountOut = 0;
-            error = reason;
-        }
+        }));
     }
 
-
-    function swapExactOutput(SwapParams memory params) internal returns (string memory error, uint256 amountIn)
+    function swapExactOutput(SwapParams memory params) internal returns (uint256 amountIn)
     {
         //     struct ExactOutputSingleParams {
         //        address tokenIn;
@@ -60,20 +52,13 @@ library UniswapSwapper {
         uint256 balance = IERC20(params.tokenIn).balanceOf(t);
         if( balance == 0 ) {
             // todo dust?
-            return ('IIA', 0);
+            revert('IIA');
         }
-        try Constants.uniswapV3SwapRouter.exactOutputSingle(ISwapRouter.ExactOutputSingleParams({
-            tokenIn: params.tokenIn, tokenOut: params.tokenOut, fee: params.fee, recipient: t, // todo return directly to wallet?
+        return Constants.uniswapV3SwapRouter.exactOutputSingle(ISwapRouter.ExactOutputSingleParams({
+            tokenIn: params.tokenIn, tokenOut: params.tokenOut, fee: params.fee, recipient: params.recipient,
             deadline: block.timestamp, amountOut: params.amount, amountInMaximum: balance,     // todo use only the committed allocation?
             sqrtPriceLimitX96: params.sqrtPriceLimitX96
-        })) returns (uint256 filledIn) {
-            amountIn = filledIn;
-            error = Constants.SWAP_OK;
-        }
-        catch Error(string memory reason) {
-            amountIn = 0;
-            error = reason;
-        }
+        }));
     }
 
 }
diff --git a/src/Vault.sol b/src/Vault.sol
index 613962f..d49aa58 100644
--- a/src/Vault.sol
+++ b/src/Vault.sol
@@ -10,6 +10,8 @@ import "forge-std/console2.sol";
 
 
 contract Vault {
+    // represents the interests of its owner client
+
     using OrderLib for OrderLib.OrdersInfo;
 
     uint8 public immutable version;
@@ -67,9 +69,8 @@ contract Vault {
     }
 
     function execute(uint64 orderIndex, uint8 tranche_index, OrderLib.PriceProof memory proof) public
-    returns (string memory error)
     {
-        return orderList.execute(orderIndex, tranche_index, proof);
+        orderList.execute(owner, orderIndex, tranche_index, proof);
     }
 
     modifier onlyOwner() {
diff --git a/src/VaultAddress.sol b/src/VaultAddress.sol
index 18cc930..2591884 100644
--- a/src/VaultAddress.sol
+++ b/src/VaultAddress.sol
@@ -10,7 +10,7 @@ library VaultAddress {
     // keccak-256 hash of the Vault's bytecode (not the deployed bytecode but the initialization bytecode)
     // can paste into:
     // https://emn178.github.io/online-tools/keccak_256.html
-    bytes32 internal constant VAULT_INIT_CODE_HASH = 0x3c95480d723e6cf3e130cfb53bfa2f15bd0bfc628246f77dfabe64ff943af969;
+    bytes32 internal constant VAULT_INIT_CODE_HASH = 0x94dd1e2fe4a67770f9295aff1b352fb0792647d2377cd96aa72e4c3a3222aad1;
 
     // the contract being constructed must not have any constructor arguments or the determinism will be broken.  instead, use a callback to
     // get construction arguments