diff --git a/db/utils.go b/db/utils.go
index f376736..901d8d4 100644
--- a/db/utils.go
+++ b/db/utils.go
@@ -13,9 +13,9 @@ import (
 	"github.com/hermeznetwork/hermez-node/log"
 	"github.com/hermeznetwork/tracerr"
 	"github.com/jmoiron/sqlx"
-	"github.com/marusama/semaphore/v2"
 	migrate "github.com/rubenv/sql-migrate"
 	"github.com/russross/meddler"
+	"golang.org/x/sync/semaphore"
 )
 
 var migrations *migrate.PackrMigrationSource
@@ -89,14 +89,14 @@ func InitSQLDB(port int, host, user, password, name string) (*sqlx.DB, error) {
 
 // APIConnectionController is used to limit the SQL open connections used by the API
 type APIConnectionController struct {
-	smphr   semaphore.Semaphore
+	smphr   *semaphore.Weighted
 	timeout time.Duration
 }
 
 // NewAPICnnectionController initialize APIConnectionController
 func NewAPICnnectionController(maxConnections int, timeout time.Duration) *APIConnectionController {
 	return &APIConnectionController{
-		smphr:   semaphore.New(maxConnections),
+		smphr:   semaphore.NewWeighted(int64(maxConnections)),
 		timeout: timeout,
 	}
 }
diff --git a/go.mod b/go.mod
index 11924f5..4464c98 100644
--- a/go.mod
+++ b/go.mod
@@ -17,7 +17,6 @@ require (
 	github.com/jmoiron/sqlx v1.2.1-0.20200615141059-0794cb1f47ee
 	github.com/joho/godotenv v1.3.0
 	github.com/lib/pq v1.8.0
-	github.com/marusama/semaphore/v2 v2.4.1
 	github.com/mattn/go-sqlite3 v2.0.3+incompatible
 	github.com/miguelmota/go-ethereum-hdwallet v0.0.0-20200123000308-a60dcd172b4c
 	github.com/mitchellh/copystructure v1.0.0
@@ -29,5 +28,6 @@ require (
 	go.uber.org/zap v1.16.0
 	golang.org/x/crypto v0.0.0-20201217014255-9d1352758620
 	golang.org/x/net v0.0.0-20200822124328-c89045814202
+	golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9
 	gopkg.in/go-playground/validator.v9 v9.29.1
 )
diff --git a/go.sum b/go.sum
index fd813a8..e06a659 100644
--- a/go.sum
+++ b/go.sum
@@ -415,9 +415,6 @@ github.com/markbates/oncer v1.0.0 h1:E83IaVAHygyndzPimgUYJjbshhDTALZyXxvk9FOlQRY
 github.com/markbates/oncer v1.0.0/go.mod h1:Z59JA581E9GP6w96jai+TGqafHPW+cPfRxz2aSZ0mcI=
 github.com/markbates/safe v1.0.1 h1:yjZkbvRM6IzKj9tlu/zMJLS0n/V351OZWRnF3QfaUxI=
 github.com/markbates/safe v1.0.1/go.mod h1:nAqgmRi7cY2nqMc92/bSEeQA+R4OheNU2T1kNSCBdG0=
-github.com/marusama/semaphore v0.0.0-20190110074507-6952cef993b2 h1:sq+a5mb8zHbmHhrIH06oqIMGsanjpbxNgxEgZVfgpvQ=
-github.com/marusama/semaphore/v2 v2.4.1 h1:Y29DhhFMvreVgoqF9EtaSJAF9t2E7Sk7i5VW81sqB8I=
-github.com/marusama/semaphore/v2 v2.4.1/go.mod h1:z9nMiNUekt/LTpTUQdpp+4sJeYqUGpwMHfW0Z8V8fnQ=
 github.com/mattn/go-colorable v0.0.9/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
 github.com/mattn/go-colorable v0.1.0/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
 github.com/mattn/go-colorable v0.1.2 h1:/bC9yWikZXAL9uJdulbSfyVNIR3n3trXl+v8+1sx8mU=