diff --git a/internal/jsonstore/jsonstore.go b/internal/jsonstore/jsonstore.go
index c0321bad..598a6eea 100644
--- a/internal/jsonstore/jsonstore.go
+++ b/internal/jsonstore/jsonstore.go
@@ -2,7 +2,6 @@ package jsonstore
 
 import (
 	"encoding/json"
-	"maps"
 	"os"
 	"path/filepath"
 	"reflect"
@@ -114,7 +113,7 @@ func (s *MapStore[VT]) Initialize() {
 }
 
 func (s MapStore[VT]) MarshalJSON() ([]byte, error) {
-	return sonic.Marshal(maps.Collect(s.Range))
+	return sonic.Marshal(xsync.ToPlainMap(s.Map))
 }
 
 func (s *MapStore[VT]) UnmarshalJSON(data []byte) error {
diff --git a/internal/net/types/url.go b/internal/net/types/url.go
index 82a04ded..dcc1ebaf 100644
--- a/internal/net/types/url.go
+++ b/internal/net/types/url.go
@@ -3,6 +3,7 @@ package nettypes
 import (
 	urlPkg "net/url"
 
+	"github.com/bytedance/sonic"
 	"github.com/yusing/godoxy/internal/utils"
 )
 
@@ -48,7 +49,7 @@ func (u *URL) MarshalJSON() (text []byte, err error) {
 	if u == nil {
 		return []byte("null"), nil
 	}
-	return []byte("\"" + u.URL.String() + "\""), nil
+	return sonic.Marshal(u.URL.String())
 }
 
 func (u *URL) Equals(other *URL) bool {
diff --git a/internal/types/health.go b/internal/types/health.go
index 14f8e75a..797c08f3 100644
--- a/internal/types/health.go
+++ b/internal/types/health.go
@@ -58,7 +58,7 @@ type (
 		LastSeenStr string             `json:"lastSeenStr"`
 		Detail      string             `json:"detail"`
 		URL         string             `json:"url"`
-		Extra       *HealthExtra       `json:"extra" extensions:"x-nullable"`
+		Extra       *HealthExtra       `json:"extra,omitempty" extensions:"x-nullable"`
 	} // @name HealthJSON
 
 	HealthJSONRepr struct {