diff --git a/ydb/core/viewer/json_pipe_req.cpp b/ydb/core/viewer/json_pipe_req.cpp
index 804e7f37c0e7..7c6ba74a792c 100644
--- a/ydb/core/viewer/json_pipe_req.cpp
+++ b/ydb/core/viewer/json_pipe_req.cpp
@@ -21,7 +21,7 @@ TViewerPipeClient::TViewerPipeClient(NWilson::TTraceId traceId) {
     }
 }
 
-TViewerPipeClient::TViewerPipeClient(IViewer* viewer, NMon::TEvHttpInfo::TPtr& ev)
+TViewerPipeClient::TViewerPipeClient(IViewer* viewer, NMon::TEvHttpInfo::TPtr& ev, const TString& handlerName)
     : Viewer(viewer)
     , Event(ev)
 {
@@ -48,7 +48,7 @@ TViewerPipeClient::TViewerPipeClient(IViewer* viewer, NMon::TEvHttpInfo::TPtr& e
         traceId = NWilson::TTraceId::NewTraceId(verbosity, ttl);
     }
     if (traceId) {
-        Span = {TComponentTracingLevels::THttp::TopLevel, std::move(traceId), "http", NWilson::EFlags::AUTO_END};
+        Span = {TComponentTracingLevels::THttp::TopLevel, std::move(traceId), handlerName ? "http " + handlerName : "http viewer", NWilson::EFlags::AUTO_END};
         Span.Attribute("request_type", TString(Event->Get()->Request.GetUri().Before('?')));
     }
 }
diff --git a/ydb/core/viewer/json_pipe_req.h b/ydb/core/viewer/json_pipe_req.h
index e3e5f3897fe4..f323d371dbf6 100644
--- a/ydb/core/viewer/json_pipe_req.h
+++ b/ydb/core/viewer/json_pipe_req.h
@@ -170,7 +170,7 @@ class TViewerPipeClient : public TActorBootstrapped<TViewerPipeClient> {
     ~TViewerPipeClient();
     TViewerPipeClient();
     TViewerPipeClient(NWilson::TTraceId traceId);
-    TViewerPipeClient(IViewer* viewer, NMon::TEvHttpInfo::TPtr& ev);
+    TViewerPipeClient(IViewer* viewer, NMon::TEvHttpInfo::TPtr& ev, const TString& handlerName = {});
     TActorId ConnectTabletPipe(TTabletId tabletId);
     void SendEvent(std::unique_ptr<IEventHandle> event);
     void SendRequest(TActorId recipient, IEventBase* ev, ui32 flags = 0, ui64 cookie = 0, NWilson::TTraceId traceId = {});
diff --git a/ydb/core/viewer/storage_groups.h b/ydb/core/viewer/storage_groups.h
index bf76665b3d10..8b647f2c415c 100644
--- a/ydb/core/viewer/storage_groups.h
+++ b/ydb/core/viewer/storage_groups.h
@@ -635,7 +635,7 @@ class TStorageGroups : public TViewerPipeClient {
     }
 
     TStorageGroups(IViewer* viewer, NMon::TEvHttpInfo::TPtr& ev)
-        : TBase(viewer, ev)
+        : TBase(viewer, ev, "/storage/groups")
     {
         const auto& params(Event->Get()->Request.GetParams());
         Timeout = FromStringWithDefault<ui32>(params.Get("timeout"), 10000);
@@ -1351,6 +1351,7 @@ class TStorageGroups : public TViewerPipeClient {
             }
         }
         if (AreBSControllerRequestsDone() && FieldsNeeded(FieldsWbDisks)) {
+            AddEvent("SendWhiteboardRequests");
             for (TGroup* group : GroupView) {
                 for (TNodeId nodeId : group->VDiskNodeIds) {
                     SendWhiteboardDisksRequest(nodeId);
@@ -1881,6 +1882,7 @@ class TStorageGroups : public TViewerPipeClient {
     }
 
     void ReplyAndPassAway() override {
+        AddEvent("ReplyAndPassAway");
         ApplyEverything();
         NKikimrViewer::TStorageGroupsInfo json;
         json.SetVersion(Viewer->GetCapabilityVersion("/storage/groups"));
@@ -1977,12 +1979,14 @@ class TStorageGroups : public TViewerPipeClient {
                 jsonGroupGroup.SetGroupCount(groupGroup.Groups.size());
             }
         }
+        AddEvent("RenderingResult");
         TStringStream out;
         Proto2Json(json, out, {
             .EnumMode = TProto2JsonConfig::EnumValueMode::EnumName,
             .StringifyNumbers = TProto2JsonConfig::EStringifyNumbersMode::StringifyInt64Always,
             .WriteNanAsString = true,
         });
+        AddEvent("ResultReady");
         TBase::ReplyAndPassAway(GetHTTPOKJSON(out.Str()));
     }
 
diff --git a/ydb/core/viewer/viewer_nodes.h b/ydb/core/viewer/viewer_nodes.h
index 0ab247971b12..acde455829a9 100644
--- a/ydb/core/viewer/viewer_nodes.h
+++ b/ydb/core/viewer/viewer_nodes.h
@@ -600,13 +600,8 @@ class TJsonNodes : public TViewerPipeClient {
     }
 
 public:
-    TString GetLogPrefix() {
-        static TString prefix = "json/nodes ";
-        return prefix;
-    }
-
     TJsonNodes(IViewer* viewer, NMon::TEvHttpInfo::TPtr& ev)
-        : TBase(viewer, ev)
+        : TBase(viewer, ev, "/viewer/nodes")
     {
         const auto& params(Event->Get()->Request.GetParams());
         JsonSettings.EnumAsNumbers = !FromStringWithDefault<bool>(params.Get("enums"), true);
@@ -1600,7 +1595,7 @@ class TJsonNodes : public TViewerPipeClient {
     void SendWhiteboardSystemAndTabletsBatch(TNodeBatch& batch) {
         TNodeId nodeId = OffloadMerge ? batch.ChooseNodeId() : 0;
         if (batch.HasStaticNodes && (FieldsNeeded(FieldsVDisks) || FieldsNeeded(FieldsPDisks))) {
-            nodeId = 0; // we need to ask for all nodes anyway
+            nodeId = 0; // we need to ask for all nodes anyway (for the compatibility with older versions)
         }
         if (nodeId) {
             if (FieldsNeeded(FieldsSystemState) && SystemViewerResponse.count(nodeId) == 0) {
@@ -2221,12 +2216,15 @@ class TJsonNodes : public TViewerPipeClient {
                 jsonNodeGroup.SetNodeCount(nodeGroup.Nodes.size());
             }
         }
+        AddEvent("RenderingResult");
         TStringStream out;
         Proto2Json(json, out, {
             .EnumMode = TProto2JsonConfig::EnumValueMode::EnumName,
+            .MapAsObject = true,
             .StringifyNumbers = TProto2JsonConfig::EStringifyNumbersMode::StringifyInt64Always,
             .WriteNanAsString = true,
         });
+        AddEvent("ResultReady");
         TBase::ReplyAndPassAway(GetHTTPOKJSON(out.Str()));
     }