diff --git a/internal/ethapi/backend.go b/internal/ethapi/backend.go
index 91a1b5806a..245091df35 100644
--- a/internal/ethapi/backend.go
+++ b/internal/ethapi/backend.go
@@ -79,6 +79,7 @@ type Backend interface {
 	GetLogs(ctx context.Context, blockHash common.Hash) ([][]*types.Log, error)
 	ServiceFilter(ctx context.Context, session *bloombits.MatcherSession)
 	SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscription
+	SubscribePendingLogsEvent(ch chan<- []*types.Log) event.Subscription
 	SubscribeRemovedLogsEvent(ch chan<- core.RemovedLogsEvent) event.Subscription
 
 	ChainConfig() *params.ChainConfig