diff --git a/web/service/client.go b/web/service/client.go
index 1109da6c..9086f80b 100644
--- a/web/service/client.go
+++ b/web/service/client.go
@@ -24,6 +24,35 @@ type ClientWithAttachments struct {
 	Traffic    *xray.ClientTraffic `json:"traffic,omitempty"`
 }
 
+// MarshalJSON is required because model.ClientRecord defines its own
+// MarshalJSON. Go promotes the embedded method to the outer struct, so without
+// this the encoder would call ClientRecord.MarshalJSON for the whole value and
+// silently drop InboundIds and Traffic from the API response.
+func (c ClientWithAttachments) MarshalJSON() ([]byte, error) {
+	rec, err := json.Marshal(c.ClientRecord)
+	if err != nil {
+		return nil, err
+	}
+	extras := struct {
+		InboundIds []int               `json:"inboundIds"`
+		Traffic    *xray.ClientTraffic `json:"traffic,omitempty"`
+	}{InboundIds: c.InboundIds, Traffic: c.Traffic}
+	extra, err := json.Marshal(extras)
+	if err != nil {
+		return nil, err
+	}
+	if len(rec) < 2 || rec[len(rec)-1] != '}' || len(extra) <= 2 {
+		return rec, nil
+	}
+	out := make([]byte, 0, len(rec)+len(extra))
+	out = append(out, rec[:len(rec)-1]...)
+	if len(rec) > 2 {
+		out = append(out, ',')
+	}
+	out = append(out, extra[1:]...)
+	return out, nil
+}
+
 func clientKeyForProtocol(p model.Protocol, rec *model.ClientRecord) string {
 	if rec == nil {
 		return ""
diff --git a/web/service/client_test.go b/web/service/client_test.go
new file mode 100644
index 00000000..2cf8b219
--- /dev/null
+++ b/web/service/client_test.go
@@ -0,0 +1,59 @@
+package service
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/mhsanaei/3x-ui/v3/database/model"
+	"github.com/mhsanaei/3x-ui/v3/xray"
+)
+
+func TestClientWithAttachmentsMarshalJSONIncludesExtras(t *testing.T) {
+	c := ClientWithAttachments{
+		ClientRecord: model.ClientRecord{Id: 1, Email: "alice@example.com"},
+		InboundIds:   []int{3, 5},
+		Traffic:      &xray.ClientTraffic{Email: "alice@example.com", Up: 1024, Down: 4096, Enable: true},
+	}
+	out, err := json.Marshal(c)
+	if err != nil {
+		t.Fatalf("Marshal failed: %v", err)
+	}
+	var parsed map[string]any
+	if err := json.Unmarshal(out, &parsed); err != nil {
+		t.Fatalf("output is not valid JSON: %v", err)
+	}
+	if parsed["email"] != "alice@example.com" {
+		t.Errorf("expected ClientRecord fields to survive, got %v", parsed)
+	}
+	ids, ok := parsed["inboundIds"].([]any)
+	if !ok {
+		t.Fatalf("expected inboundIds to be present as an array, got %T (%s)", parsed["inboundIds"], out)
+	}
+	if len(ids) != 2 {
+		t.Errorf("expected 2 inbound ids, got %d", len(ids))
+	}
+	if _, ok := parsed["traffic"].(map[string]any); !ok {
+		t.Errorf("expected traffic to be present as an object, got %T", parsed["traffic"])
+	}
+}
+
+func TestClientWithAttachmentsMarshalJSONOmitsAbsentTraffic(t *testing.T) {
+	c := ClientWithAttachments{
+		ClientRecord: model.ClientRecord{Id: 1, Email: "bob@example.com"},
+		InboundIds:   nil,
+	}
+	out, err := json.Marshal(c)
+	if err != nil {
+		t.Fatalf("Marshal failed: %v", err)
+	}
+	var parsed map[string]any
+	if err := json.Unmarshal(out, &parsed); err != nil {
+		t.Fatalf("output is not valid JSON: %v", err)
+	}
+	if _, present := parsed["traffic"]; present {
+		t.Errorf("expected traffic to be omitted when nil, got %v", parsed["traffic"])
+	}
+	if _, present := parsed["inboundIds"]; !present {
+		t.Errorf("expected inboundIds key to always be present, got %s", out)
+	}
+}