diff --git a/backend.go b/backend.go
index 129dc5f..51e348e 100644
--- a/backend.go
+++ b/backend.go
@@ -3,6 +3,7 @@ package main
 import (
 	"net/http"
 	"net/url"
+	"slices"
 
 	"github.com/mercari/go-circuitbreaker"
 )
@@ -56,12 +57,7 @@ func init() {
 			if !ok {
 				return false
 			}
-			for _, got := range values {
-				if value == got {
-					return true
-				}
-			}
-			return false
+			return slices.Contains(values, value)
 		}
 	}
 }
diff --git a/delegated_translator.go b/delegated_translator.go
index 7d1f499..5bb2cc9 100644
--- a/delegated_translator.go
+++ b/delegated_translator.go
@@ -238,7 +238,7 @@ func drProvFromResult(p model.ProviderResult) *drProvider {
 }
 
 func (dp drProvider) MarshalJSON() ([]byte, error) {
-	m := map[string]interface{}{}
+	m := map[string]any{}
 	if dp.Metadata != nil {
 		for key, val := range dp.Metadata {
 			m[key] = val
diff --git a/header.go b/header.go
index 6987510..0f28923 100644
--- a/header.go
+++ b/header.go
@@ -24,8 +24,8 @@ func getAccepts(r *http.Request) (accepts, error) {
 	values := r.Header.Values("Accept")
 	a.acceptHeaderFound = len(values) > 0
 	for _, accept := range values {
-		amts := strings.Split(accept, ",")
-		for _, amt := range amts {
+		amts := strings.SplitSeq(accept, ",")
+		for amt := range amts {
 			if mt, _, err := mime.ParseMediaType(amt); err != nil {
 				return a, err
 			} else if mt == mediaTypeNDJson {