diff --git a/src/cache/cache.go b/src/cache/cache.go
index 311d79e..e7a5540 100644
--- a/src/cache/cache.go
+++ b/src/cache/cache.go
@@ -1,13 +1,9 @@
 package cache
 
 import (
-	"fmt"
 	"time"
 
-	cache_default "ytproxy/cache/impl/default"
-	cache_empty "ytproxy/cache/impl/empty"
 	extractor_config "ytproxy/extractor/config"
-	logger "ytproxy/logger"
 )
 
 type T interface {
@@ -19,16 +15,3 @@ type T interface {
 type ConfigT struct {
 	ExpireTime *string `json:"expire-time"`
 }
-
-func New(conf ConfigT, log logger.T) (T, error) {
-	t, err := time.ParseDuration(*conf.ExpireTime)
-	if err != nil {
-		return cache_default.New(0), err
-	}
-	if t.Seconds() < 1 {
-		log.LogDebug("", "disabled by config")
-		return cache_empty.New(), nil
-	}
-	log.LogDebug("", fmt.Sprintf("expire time set to %s", t))
-	return cache_default.New(t), nil
-}
diff --git a/src/cache/impl/default/default.go b/src/cache/impl/default/default.go
index 266d050..3ec8908 100644
--- a/src/cache/impl/default/default.go
+++ b/src/cache/impl/default/default.go
@@ -4,9 +4,12 @@ import (
 	"sync"
 	"time"
 
+	cache "ytproxy/cache"
 	extractor_config "ytproxy/extractor/config"
 )
 
+var _ cache.T = (*defaultCache)(nil)
+
 func New(t time.Duration) *defaultCache {
 	return &defaultCache{
 		cache:      make(map[extractor_config.RequestT]extractor_config.ResultT),
diff --git a/src/cache/mux/mux.go b/src/cache/mux/mux.go
new file mode 100644
index 0000000..17f1b21
--- /dev/null
+++ b/src/cache/mux/mux.go
@@ -0,0 +1,24 @@
+package cache
+
+import (
+	"fmt"
+	"time"
+
+	cache "ytproxy/cache"
+	cache_default "ytproxy/cache/impl/default"
+	cache_empty "ytproxy/cache/impl/empty"
+	logger "ytproxy/logger"
+)
+
+func New(conf cache.ConfigT, log logger.T) (cache.T, error) {
+	t, err := time.ParseDuration(*conf.ExpireTime)
+	if err != nil {
+		return cache_default.New(0), err
+	}
+	if t.Seconds() < 1 {
+		log.LogDebug("", "disabled by config")
+		return cache_empty.New(), nil
+	}
+	log.LogDebug("", fmt.Sprintf("expire time set to %s", t))
+	return cache_default.New(t), nil
+}
diff --git a/src/go.mod b/src/go.mod
index ed9b482..4edeb00 100644
--- a/src/go.mod
+++ b/src/go.mod
@@ -1,3 +1,3 @@
 module ytproxy
 
-go 1.22.6
+go 1.18
diff --git a/src/main.go b/src/main.go
index fd0f19b..f0d1659 100644
--- a/src/main.go
+++ b/src/main.go
@@ -10,7 +10,7 @@ import (
 	"syscall"
 
 	app "ytproxy/app"
-	cache "ytproxy/cache"
+	cache_mux "ytproxy/cache/mux"
 	config "ytproxy/config"
 	extractor "ytproxy/extractor"
 	logger "ytproxy/logger"
@@ -192,7 +192,7 @@ func getNewApp(log logger.T, v config.SubConfigT) (app.Option, error) {
 	if err != nil {
 		return app.Option{}, nameerr(texts[0], err)
 	}
-	cch, err := cache.New(v.Cache,
+	cch, err := cache_mux.New(v.Cache,
 		logger.NewLayer(log, newname(texts[1])))
 	if err != nil {
 		return app.Option{}, nameerr(texts[1], err)