diff --git a/pkg/api.go b/pkg/api.go
index f22db38..334268e 100644
--- a/pkg/api.go
+++ b/pkg/api.go
@@ -17,6 +17,7 @@ package statediff
 
 import (
 	"context"
+
 	sd "github.com/ethereum/go-ethereum/statediff"
 )
 
diff --git a/pkg/builder.go b/pkg/builder.go
index 5b8968e..742c1f7 100644
--- a/pkg/builder.go
+++ b/pkg/builder.go
@@ -22,8 +22,8 @@ package statediff
 import (
 	"bytes"
 	"fmt"
-	"sync"
 	"math/bits"
+	"sync"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/state"
@@ -33,14 +33,15 @@ import (
 	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/ethereum/go-ethereum/trie"
 
-	iter "github.com/vulcanize/go-eth-state-node-iterator"
 	sd "github.com/ethereum/go-ethereum/statediff"
+	iter "github.com/vulcanize/go-eth-state-node-iterator"
 )
 
 var (
 	nullHashBytes     = common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000000")
 	emptyNode, _      = rlp.EncodeToBytes([]byte{})
 	emptyContractRoot = crypto.Keccak256Hash(emptyNode)
+	nullCodeHash      = crypto.Keccak256Hash([]byte{}).Bytes()
 )
 
 // Builder interface exposes the method for building a state diff between two blocks
@@ -79,14 +80,15 @@ func (sdb *builder) BuildStateTrieObject(current *types.Block) (sd.StateObject,
 		return sd.StateObject{}, fmt.Errorf("error creating trie for block %d: %v", current.Number(), err)
 	}
 	it := currentTrie.NodeIterator([]byte{})
-	stateNodes, err := sdb.buildStateTrie(it)
+	stateNodes, codeAndCodeHashes, err := sdb.buildStateTrie(it)
 	if err != nil {
 		return sd.StateObject{}, fmt.Errorf("error collecting state nodes for block %d: %v", current.Number(), err)
 	}
 	return sd.StateObject{
-		BlockNumber: current.Number(),
-		BlockHash:   current.Hash(),
-		Nodes:       stateNodes,
+		BlockNumber:       current.Number(),
+		BlockHash:         current.Hash(),
+		Nodes:             stateNodes,
+		CodeAndCodeHashes: codeAndCodeHashes,
 	}, nil
 }
 
@@ -112,49 +114,76 @@ func resolveNode(it trie.NodeIterator, trieDB *trie.Database) (sd.StateNode, []i
 	}, nodeElements, nil
 }
 
-func (sdb *builder) buildStateTrie(it trie.NodeIterator) ([]sd.StateNode, error) {
+func (sdb *builder) buildStateTrie(it trie.NodeIterator) ([]sd.StateNode, []sd.CodeAndCodeHash, error) {
 	stateNodes := make([]sd.StateNode, 0)
+	codeAndCodeHashes := make([]sd.CodeAndCodeHash, 0)
 	for it.Next(true) {
 		// skip value nodes
-		if it.Leaf() || bytes.Equal(nullHashBytes, it.Hash().Bytes()) {
+		if it.Leaf() {
 			continue
 		}
-		node, nodeElements, err := resolveNode(it, sdb.stateCache.TrieDB())
-		if err != nil {
-			return nil, err
+		if bytes.Equal(nullHashBytes, it.Hash().Bytes()) {
+			continue
 		}
-		switch node.NodeType {
+		nodePath := make([]byte, len(it.Path()))
+		copy(nodePath, it.Path())
+		node, err := sdb.stateCache.TrieDB().Node(it.Hash())
+		if err != nil {
+			return nil, nil, err
+		}
+		var nodeElements []interface{}
+		if err := rlp.DecodeBytes(node, &nodeElements); err != nil {
+			return nil, nil, err
+		}
+		ty, err := sd.CheckKeyType(nodeElements)
+		if err != nil {
+			return nil, nil, err
+		}
+		switch ty {
 		case sd.Leaf:
 			var account state.Account
 			if err := rlp.DecodeBytes(nodeElements[1].([]byte), &account); err != nil {
-				return nil, fmt.Errorf("error decoding account for leaf node at path %x nerror: %v", node.Path, err)
+				return nil, nil, fmt.Errorf("error decoding account for leaf node at path %x nerror: %v", nodePath, err)
 			}
 			partialPath := trie.CompactToHex(nodeElements[0].([]byte))
-			valueNodePath := append(node.Path, partialPath...)
+			valueNodePath := append(nodePath, partialPath...)
 			encodedPath := trie.HexToCompact(valueNodePath)
 			leafKey := encodedPath[1:]
-			storageNodes, err := sdb.buildStorageNodesEventual(account.Root, nil, true)
-			if err != nil {
-				return nil, fmt.Errorf("failed building eventual storage diffs for account %+v\r\nerror: %v", account, err)
+			node := sd.StateNode{
+				NodeType:  ty,
+				Path:      nodePath,
+				LeafKey:   leafKey,
+				NodeValue: node,
 			}
-			stateNodes = append(stateNodes, sd.StateNode{
-				NodeType:     node.NodeType,
-				Path:         node.Path,
-				LeafKey:      leafKey,
-				NodeValue:    node.NodeValue,
-				StorageNodes: storageNodes,
-			})
+			if !bytes.Equal(account.CodeHash, nullCodeHash) {
+				storageNodes, err := sdb.buildStorageNodesEventual(account.Root, nil, true)
+				if err != nil {
+					return nil, nil, fmt.Errorf("failed building eventual storage diffs for account %+v\r\nerror: %v", account, err)
+				}
+				node.StorageNodes = storageNodes
+				// emit codehash => code mappings for cod
+				codeHash := common.BytesToHash(account.CodeHash)
+				code, err := sdb.stateCache.ContractCode(common.Hash{}, codeHash)
+				if err != nil {
+					return nil, nil, fmt.Errorf("failed to retrieve code for codehash %s\r\n error: %v", codeHash.String(), err)
+				}
+				codeAndCodeHashes = append(codeAndCodeHashes, sd.CodeAndCodeHash{
+					Hash: codeHash,
+					Code: code,
+				})
+			}
+			stateNodes = append(stateNodes, node)
 		case sd.Extension, sd.Branch:
 			stateNodes = append(stateNodes, sd.StateNode{
-				NodeType:  node.NodeType,
-				Path:      node.Path,
-				NodeValue: node.NodeValue,
+				NodeType:  ty,
+				Path:      nodePath,
+				NodeValue: node,
 			})
 		default:
-			return nil, fmt.Errorf("unexpected node type %s", node.NodeType)
+			return nil, nil, fmt.Errorf("unexpected node type %s", ty)
 		}
 	}
-	return stateNodes, it.Error()
+	return stateNodes, codeAndCodeHashes, it.Error()
 }
 
 // BuildStateDiff builds a statediff object from two blocks and the provided parameters
@@ -195,7 +224,12 @@ func (sdb *builder) BuildStateDiffObject(args sd.Args, params sd.Params) (sd.Sta
 		}
 	}
 
-	nodeChan := make(chan []sd.StateNode)
+	type packet struct {
+		nodes []sd.StateNode
+		codes []sd.CodeAndCodeHash
+	}
+
+	packetChan := make(chan packet)
 	var wg sync.WaitGroup
 
 	for w := uint(0); w < sdb.numWorkers; w++ {
@@ -203,49 +237,55 @@ func (sdb *builder) BuildStateDiffObject(args sd.Args, params sd.Params) (sd.Sta
 		go func(iterChan <-chan []iterPair) error {
 			defer wg.Done()
 			if iters, more := <-iterChan; more {
-				subtrieNodes, err := sdb.buildStateDiff(iters, params)
+				subtrieNodes, subtrieCodes, err := sdb.buildStateDiff(iters, params)
 				if err != nil {
 					return err
 				}
-				nodeChan <- subtrieNodes
+				packetChan <- packet{
+					nodes: subtrieNodes,
+					codes: subtrieCodes,
+				}
 			}
 			return nil
 		}(iterChan)
 	}
 
 	go func() {
-		defer close(nodeChan)
+		defer close(packetChan)
 		defer close(iterChan)
 		wg.Wait()
 	}()
 
 	stateNodes := make([]sd.StateNode, 0)
-	for subtrieNodes := range nodeChan {
-		stateNodes = append(stateNodes, subtrieNodes...)
+	codeAndCodeHashes := make([]sd.CodeAndCodeHash, 0)
+	for packet := range packetChan {
+		stateNodes = append(stateNodes, packet.nodes...)
+		codeAndCodeHashes = append(codeAndCodeHashes, packet.codes...)
 	}
 
 	return sd.StateObject{
-		BlockHash:   args.BlockHash,
-		BlockNumber: args.BlockNumber,
-		Nodes:       stateNodes,
+		BlockHash:         args.BlockHash,
+		BlockNumber:       args.BlockNumber,
+		Nodes:             stateNodes,
+		CodeAndCodeHashes: codeAndCodeHashes,
 	}, nil
 }
 
-func (sdb *builder) buildStateDiff(args []iterPair, params sd.Params) ([]sd.StateNode, error) {
+func (sdb *builder) buildStateDiff(args []iterPair, params sd.Params) ([]sd.StateNode, []sd.CodeAndCodeHash, error) {
 	// collect a slice of all the intermediate nodes that were touched and exist at B
 	// a map of their leafkey to all the accounts that were touched and exist at B
 	// and a slice of all the paths for the nodes in both of the above sets
 	createdOrUpdatedIntermediateNodes, diffAccountsAtB, diffPathsAtB, err := sdb.createdAndUpdatedState(
 		args[0], params.WatchedAddresses, params.IntermediateStateNodes)
 	if err != nil {
-		return nil, fmt.Errorf("error collecting createdAndUpdatedNodes: %v", err)
+		return nil, nil, fmt.Errorf("error collecting createdAndUpdatedNodes: %v", err)
 	}
 
 	// collect a slice of all the nodes that existed at a path in A that doesn't exist in B
 	// a map of their leafkey to all the accounts that were touched and exist at A
 	emptiedPaths, diffAccountsAtA, err := sdb.deletedOrUpdatedState(args[1], diffPathsAtB)
 	if err != nil {
-		return nil, fmt.Errorf("error collecting deletedOrUpdatedNodes: %v", err)
+		return nil, nil, fmt.Errorf("error collecting deletedOrUpdatedNodes: %v", err)
 	}
 
 	// collect and sort the leafkey keys for both account mappings into a slice
@@ -264,28 +304,24 @@ func (sdb *builder) buildStateDiff(args []iterPair, params sd.Params) ([]sd.Stat
 		diffAccountsAtB, diffAccountsAtA, updatedKeys,
 		params.WatchedStorageSlots, params.IntermediateStorageNodes)
 	if err != nil {
-		return nil, fmt.Errorf("error building diff for updated accounts: %v", err)
+		return nil, nil, fmt.Errorf("error building diff for updated accounts: %v", err)
 	}
 	// build the diff nodes for created accounts
-	createdAccounts, err := sdb.buildAccountCreations(
+	createdAccounts, codeAndCodeHashes, err := sdb.buildAccountCreations(
 		diffAccountsAtB, params.WatchedStorageSlots, params.IntermediateStorageNodes)
 	if err != nil {
-		return nil, fmt.Errorf("error building diff for created accounts: %v", err)
+		return nil, nil, fmt.Errorf("error building diff for created accounts: %v", err)
 	}
 
 	// assemble all of the nodes into the statediff object, including the intermediate nodes
-	res := append(
+	nodes := append(
 		append(
 			append(updatedAccounts, createdAccounts...),
 			createdOrUpdatedIntermediateNodes...,
 		),
 		emptiedPaths...)
 
-	var paths [][]byte
-	for _, n := range res {
-		paths = append(paths, n.Path)
-	}
-	return res, nil
+	return nodes, codeAndCodeHashes, nil
 }
 
 // createdAndUpdatedState returns
@@ -430,24 +466,39 @@ func (sdb *builder) buildAccountUpdates(creations, deletions AccountMap, updated
 }
 
 // buildAccountCreations returns the statediff node objects for all the accounts that exist at B but not at A
-func (sdb *builder) buildAccountCreations(accounts AccountMap, watchedStorageKeys []common.Hash, intermediateStorageNodes bool) ([]sd.StateNode, error) {
+// it also returns the code and codehash for created contract accounts
+func (sdb *builder) buildAccountCreations(accounts AccountMap, watchedStorageKeys []common.Hash, intermediateStorageNodes bool) ([]sd.StateNode, []sd.CodeAndCodeHash, error) {
 	accountDiffs := make([]sd.StateNode, 0, len(accounts))
+	codeAndCodeHashes := make([]sd.CodeAndCodeHash, 0)
 	for _, val := range accounts {
-		// For account creations, any storage node contained is a diff
-		storageDiffs, err := sdb.buildStorageNodesEventual(val.Account.Root, watchedStorageKeys, intermediateStorageNodes)
-		if err != nil {
-			return nil, fmt.Errorf("failed building eventual storage diffs for node %x\r\nerror: %v", val.Path, err)
+		diff := sd.StateNode{
+			NodeType:  val.NodeType,
+			Path:      val.Path,
+			LeafKey:   val.LeafKey,
+			NodeValue: val.NodeValue,
 		}
-		accountDiffs = append(accountDiffs, sd.StateNode{
-			NodeType:     val.NodeType,
-			Path:         val.Path,
-			LeafKey:      val.LeafKey,
-			NodeValue:    val.NodeValue,
-			StorageNodes: storageDiffs,
-		})
+		if !bytes.Equal(val.Account.CodeHash, nullCodeHash) {
+			// For contract creations, any storage node contained is a diff
+			storageDiffs, err := sdb.buildStorageNodesEventual(val.Account.Root, watchedStorageKeys, intermediateStorageNodes)
+			if err != nil {
+				return nil, nil, fmt.Errorf("failed building eventual storage diffs for node %x\r\nerror: %v", val.Path, err)
+			}
+			diff.StorageNodes = storageDiffs
+			// emit codehash => code mappings for new contracts
+			codeHash := common.BytesToHash(val.Account.CodeHash)
+			code, err := sdb.stateCache.ContractCode(common.Hash{}, codeHash)
+			if err != nil {
+				return nil, nil, fmt.Errorf("failed to retrieve code for codehash %s\r\n error: %v", codeHash.String(), err)
+			}
+			codeAndCodeHashes = append(codeAndCodeHashes, sd.CodeAndCodeHash{
+				Hash: codeHash,
+				Code: code,
+			})
+		}
+		accountDiffs = append(accountDiffs, diff)
 	}
 
-	return accountDiffs, nil
+	return accountDiffs, codeAndCodeHashes, nil
 }
 
 // buildStorageNodesEventual builds the storage diff node objects for a created account