diff --git a/internal/crawler/safer.go b/internal/crawler/safer.go
index ebb338d..9224241 100644
--- a/internal/crawler/safer.go
+++ b/internal/crawler/safer.go
@@ -37,7 +37,7 @@ func CrawlSafer(DOTWatermark, bucketSize, numConnections int, dao dao.Dao) (err
 	}
 
 	// map to store number of failed safer fetch in dot range segmented by bucket size.
-	// this is used to detect the upperfound of available dotnumber
+	// this is used to detect the upperbound of available dotnumber
 	notFound := sync.Map{}
 	terminate := false
 	dot := 1