diff --git a/indexer/balance_storage_handler.go b/indexer/balance_storage_handler.go
index a7d768c..da1b5dd 100644
--- a/indexer/balance_storage_handler.go
+++ b/indexer/balance_storage_handler.go
@@ -1,17 +1,3 @@
-// Copyright 2020 Coinbase, Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
 package indexer
 
 import (
@@ -24,6 +10,7 @@ import (
 
 var _ storage.BalanceStorageHandler = (*BalanceStorageHandler)(nil)
 
+// BalanceStorageHandler implements storage.BalanceStorageHandler.
 type BalanceStorageHandler struct{}
 
 // BlockAdded is called whenever a block is committed to BlockStorage.
diff --git a/indexer/balance_storage_helper.go b/indexer/balance_storage_helper.go
index c0445d9..3600002 100644
--- a/indexer/balance_storage_helper.go
+++ b/indexer/balance_storage_helper.go
@@ -25,6 +25,7 @@ import (
 
 var _ storage.BalanceStorageHelper = (*BalanceStorageHelper)(nil)
 
+// BalanceStorageHelper implements storage.BalanceStorageHelper.
 type BalanceStorageHelper struct {
 	a *asserter.Asserter
 }
diff --git a/indexer/coin_storage_helper.go b/indexer/coin_storage_helper.go
index 254e58b..36a7515 100644
--- a/indexer/coin_storage_helper.go
+++ b/indexer/coin_storage_helper.go
@@ -23,6 +23,7 @@ import (
 
 var _ storage.CoinStorageHelper = (*CoinStorageHelper)(nil)
 
+// CoinStorageHelper implements storage.CoinStorageHelper.
 type CoinStorageHelper struct {
 	b *storage.BlockStorage
 }