diff --git a/pkg/service.go b/pkg/service.go
index 6aa4396..6785079 100644
--- a/pkg/service.go
+++ b/pkg/service.go
@@ -41,7 +41,7 @@ const defaultQueueSize = 1024
 // Service is the underlying struct for the state diffing service
 type Service struct {
 	// Used to build the state diff objects
-	Builder statediff.Builder
+	builder statediff.Builder
 	// Used to read data from LevelDB
 	lvlDBReader Reader
 	// Used to signal shutdown of the service
@@ -65,7 +65,7 @@ func NewStateDiffService(lvlDBReader Reader, indexer interfaces.StateDiffIndexer
 	}
 	return &Service{
 		lvlDBReader: lvlDBReader,
-		Builder:     builder,
+		builder:     builder,
 		indexer:     indexer,
 		workers:     conf.ServiceWorkers,
 		queue:       make(chan RangeRequest, conf.WorkerQueueSize),
@@ -267,7 +267,7 @@ func (sds *Service) StateDiffFor(blockHash common.Hash, params statediff.Params)
 
 // processStateDiff method builds the state diff payload from the current block, parent state root, and provided params
 func (sds *Service) processStateDiff(currentBlock *types.Block, parentRoot common.Hash, params statediff.Params) (*statediff.Payload, error) {
-	stateDiff, err := sds.Builder.BuildStateDiffObject(statediff.Args{
+	stateDiff, err := sds.builder.BuildStateDiffObject(statediff.Args{
 		BlockHash:    currentBlock.Hash(),
 		BlockNumber:  currentBlock.Number(),
 		OldStateRoot: parentRoot,
@@ -413,7 +413,7 @@ func (sds *Service) writeStateDiff(block *types.Block, parentRoot common.Hash, p
 	}
 	prom.SetTimeMetric(prom.T_BLOCK_PROCESSING, time.Now().Sub(t))
 	t = time.Now()
-	err = sds.Builder.WriteStateDiff(statediff.Args{
+	err = sds.builder.WriteStateDiff(statediff.Args{
 		NewStateRoot: block.Root(),
 		OldStateRoot: parentRoot,
 		BlockNumber:  block.Number(),