diff --git a/box.go b/box.go
index b9f04c87..e7813d95 100644
--- a/box.go
+++ b/box.go
@@ -15,6 +15,7 @@ import (
 	"github.com/sagernet/sing-box/common/dialer"
 	"github.com/sagernet/sing-box/common/taskmonitor"
 	"github.com/sagernet/sing-box/common/tls"
+	"github.com/sagernet/sing-box/common/urltest"
 	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing-box/experimental"
 	"github.com/sagernet/sing-box/experimental/cachefile"
@@ -114,6 +115,9 @@ func New(options Options) (*Box, error) {
 	if experimentalOptions.V2RayAPI != nil && experimentalOptions.V2RayAPI.Listen != "" {
 		needV2RayAPI = true
 	}
+	if experimentalOptions.UnifiedDelay != nil && experimentalOptions.UnifiedDelay.Enabled {
+		ctx = urltest.ContextWithIsUnifiedDelay(ctx)
+	}
 	platformInterface := service.FromContext[platform.Interface](ctx)
 	var defaultLogWriter io.Writer
 	if platformInterface != nil {
diff --git a/common/urltest/context.go b/common/urltest/context.go
new file mode 100644
index 00000000..002ff265
--- /dev/null
+++ b/common/urltest/context.go
@@ -0,0 +1,13 @@
+package urltest
+
+import "context"
+
+type contextKeyIsUnifiedDelay struct{}
+
+func ContextWithIsUnifiedDelay(ctx context.Context) context.Context {
+	return context.WithValue(ctx, contextKeyIsUnifiedDelay{}, true)
+}
+
+func IsUnifiedDelayFromContext(ctx context.Context) bool {
+	return ctx.Value(contextKeyIsUnifiedDelay{}) != nil
+}
diff --git a/common/urltest/urltest.go b/common/urltest/urltest.go
index 9efd0404..3ddb747e 100644
--- a/common/urltest/urltest.go
+++ b/common/urltest/urltest.go
@@ -122,6 +122,15 @@ func URLTest(ctx context.Context, link string, detour N.Dialer) (t uint16, err e
 		return
 	}
 	resp.Body.Close()
+	if IsUnifiedDelayFromContext(ctx) {
+		second := time.Now()
+		resp, err = client.Do(req)
+		if err != nil {
+			return
+		}
+		resp.Body.Close()
+		start = second
+	}
 	t = uint16(time.Since(start) / time.Millisecond)
 	return
 }
diff --git a/experimental/libbox/service.go b/experimental/libbox/service.go
index 16c04a1f..d4ab3b75 100644
--- a/experimental/libbox/service.go
+++ b/experimental/libbox/service.go
@@ -69,6 +69,10 @@ func NewService(configContent string, platformInterface PlatformInterface) (*Box
 		cancel()
 		return nil, E.Cause(err, "create service")
 	}
+	experimentalOptions := common.PtrValueOrDefault(options.Experimental)
+	if experimentalOptions.UnifiedDelay != nil && experimentalOptions.UnifiedDelay.Enabled {
+		ctx = urltest.ContextWithIsUnifiedDelay(ctx)
+	}
 	runtimeDebug.FreeOSMemory()
 	return &BoxService{
 		ctx:                   ctx,
diff --git a/option/experimental.go b/option/experimental.go
index 730740a4..0487881b 100644
--- a/option/experimental.go
+++ b/option/experimental.go
@@ -3,10 +3,11 @@ package option
 import "github.com/sagernet/sing/common/json/badoption"
 
 type ExperimentalOptions struct {
-	CacheFile *CacheFileOptions `json:"cache_file,omitempty"`
-	ClashAPI  *ClashAPIOptions  `json:"clash_api,omitempty"`
-	V2RayAPI  *V2RayAPIOptions  `json:"v2ray_api,omitempty"`
-	Debug     *DebugOptions     `json:"debug,omitempty"`
+	CacheFile    *CacheFileOptions    `json:"cache_file,omitempty"`
+	ClashAPI     *ClashAPIOptions     `json:"clash_api,omitempty"`
+	V2RayAPI     *V2RayAPIOptions     `json:"v2ray_api,omitempty"`
+	UnifiedDelay *UnifiedDelayOptions `json:"unified_delay,omitempty"`
+	Debug        *DebugOptions        `json:"debug,omitempty"`
 }
 
 type CacheFileOptions struct {
@@ -53,3 +54,7 @@ type V2RayStatsServiceOptions struct {
 	Outbounds []string `json:"outbounds,omitempty"`
 	Users     []string `json:"users,omitempty"`
 }
+
+type UnifiedDelayOptions struct {
+	Enabled bool `json:"enabled,omitempty"`
+}