diff --git a/client/impl/ydb_internal/grpc_connections/grpc_connections.cpp b/client/impl/ydb_internal/grpc_connections/grpc_connections.cpp
index d8c1982bc5f..7c68bbbe9a9 100644
--- a/client/impl/ydb_internal/grpc_connections/grpc_connections.cpp
+++ b/client/impl/ydb_internal/grpc_connections/grpc_connections.cpp
@@ -389,7 +389,7 @@ bool TGRpcConnectionsImpl::StartStatCollecting(NMonitoring::IMetricRegistry* sen
         if (auto ptr = dynamic_cast<NMonitoring::TMetricRegistry*>(sensorsRegistry)) {
             MetricRegistryPtr_ = ptr;
         } else {
-            Cerr << "Unknown IMetricRegistry impl" << Endl;
+            std::cerr << "Unknown IMetricRegistry impl" << std::endl;
             return false;
         }
     }
diff --git a/client/impl/ydb_internal/retry/retry.h b/client/impl/ydb_internal/retry/retry.h
index c89ec74e0cb..2695d379888 100644
--- a/client/impl/ydb_internal/retry/retry.h
+++ b/client/impl/ydb_internal/retry/retry.h
@@ -47,9 +47,9 @@ class TRetryContextBase : TNonCopyable {
 
     void LogRetry(const TStatus& status) {
         if (Settings_.Verbose_) {
-            Cerr << "Previous query attempt was finished with unsuccessful status "
-                << status.GetStatus() << ": " << status.GetIssues().ToString(true) << Endl;
-            Cerr << "Sending retry attempt " << RetryNumber_ << " of " << Settings_.MaxRetries_ << Endl;
+            std::cerr << "Previous query attempt was finished with unsuccessful status "
+                << ToString(status.GetStatus()) << ": " << status.GetIssues().ToString(true) << std::endl;
+            std::cerr << "Sending retry attempt " << RetryNumber_ << " of " << Settings_.MaxRetries_ << std::endl;
         }
     }
 
diff --git a/client/ydb_coordination/coordination_ut.cpp b/client/ydb_coordination/coordination_ut.cpp
index abeb1ce24ab..c8e71a67dd8 100644
--- a/client/ydb_coordination/coordination_ut.cpp
+++ b/client/ydb_coordination/coordination_ut.cpp
@@ -24,7 +24,7 @@ namespace {
         {
             Y_UNUSED(context);
 
-            Cerr << "ListEndpoints: " << request->ShortDebugString() << Endl;
+            std::cerr << "ListEndpoints: " << request->ShortDebugString() << std::endl;
 
             const auto* result = MockResults.FindPtr(request->database());
             Y_ABORT_UNLESS(result, "Mock service doesn't have a result for database '%s'", request->database().c_str());
@@ -50,7 +50,7 @@ namespace {
         {
             Y_UNUSED(context);
 
-            Cerr << "Session stream started" << Endl;
+            std::cerr << "Session stream started" << std::endl;
 
             Ydb::Coordination::SessionRequest request;
 
@@ -60,7 +60,7 @@ namespace {
                     // Disconnected before the request was sent
                     return grpc::Status::OK;
                 }
-                Cerr << "Session request: " << request.ShortDebugString() << Endl;
+                std::cerr << "Session request: " << request.ShortDebugString() << std::endl;
                 Y_ABORT_UNLESS(request.has_session_start(), "Expected session start");
                 auto& start = request.session_start();
                 uint64_t sessionId = start.session_id();
@@ -77,7 +77,7 @@ namespace {
 
             size_t pings_received = 0;
             while (stream->Read(&request)) {
-                Cerr << "Session request: " << request.ShortDebugString() << Endl;
+                std::cerr << "Session request: " << request.ShortDebugString() << std::endl;
                 Y_ABORT_UNLESS(request.has_ping(), "Only ping requests are supported");
                 if (++pings_received <= 2) {
                     // Only reply to the first 2 ping requests
@@ -152,7 +152,7 @@ Y_UNIT_TEST_SUITE(Coordination) {
         auto endTimestamp = TInstant::Now();
         auto elapsed = endTimestamp - startTimestamp;
 
-        Cerr << "Got: " << res.GetStatus() << ": " << res.GetIssues().ToString() << Endl;
+        std::cerr << "Got: " << res.GetStatus() << ": " << res.GetIssues().ToString() << std::endl;
 
         // Both connection and session timeout return EStatus::TIMEOUT
         UNIT_ASSERT_VALUES_EQUAL_C(res.GetStatus(), EStatus::TIMEOUT, res.GetIssues().ToString());
@@ -168,7 +168,7 @@ Y_UNIT_TEST_SUITE(Coordination) {
         TMockCoordinationService coordinationService;
         ui16 coordinationPort = pm.GetPort();
         auto coordinationServer = StartGrpcServer(
-                TYdbStringBuilder() << "0.0.0.0:" << coordinationPort,
+                TStringBuilder() << "0.0.0.0:" << coordinationPort,
                 coordinationService);
 
         // Fill a fake discovery service
@@ -197,7 +197,7 @@ Y_UNIT_TEST_SUITE(Coordination) {
         auto stoppedFuture = stoppedPromise.GetFuture();
         auto settings = TSessionSettings()
             .OnStateChanged([](auto state) {
-                Cerr << "Session state: " << state << Endl;
+                std::cerr << "Session state: " << state << std::endl;
             })
             .OnStopped([stoppedPromise]() mutable {
                 stoppedPromise.SetValue();
@@ -221,7 +221,7 @@ Y_UNIT_TEST_SUITE(Coordination) {
 
         // Check the last failure stored in a session
         auto res2 = session.Close().ExtractValueSync();
-        Cerr << "Close: " << res2.GetStatus() << ": " << res2.GetIssues().ToString() << Endl;
+        std::cerr << "Close: " << res2.GetStatus() << ": " << res2.GetIssues().ToString() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL_C(res2.GetStatus(), EStatus::TIMEOUT, res2.GetIssues().ToString());
     }
 
@@ -261,7 +261,7 @@ Y_UNIT_TEST_SUITE(Coordination) {
         auto stoppedFuture = stoppedPromise.GetFuture();
         auto settings = TSessionSettings()
             .OnStateChanged([](auto state) {
-                Cerr << "Session state: " << state << Endl;
+                std::cerr << "Session state: " << state << std::endl;
             })
             .OnStopped([stoppedPromise]() mutable {
                 stoppedPromise.SetValue();
@@ -288,7 +288,7 @@ Y_UNIT_TEST_SUITE(Coordination) {
 
         // Check the last failure stored in a session
         auto res2 = session.Close().ExtractValueSync();
-        Cerr << "Close: " << res2.GetStatus() << ": " << res2.GetIssues().ToString() << Endl;
+        std::cerr << "Close: " << res2.GetStatus() << ": " << res2.GetIssues().ToString() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL_C(res2.GetStatus(), EStatus::CLIENT_CANCELLED, res2.GetIssues().ToString());
     }
 
diff --git a/client/ydb_driver/driver_ut.cpp b/client/ydb_driver/driver_ut.cpp
index b67963c4f16..ef893c8d0a5 100644
--- a/client/ydb_driver/driver_ut.cpp
+++ b/client/ydb_driver/driver_ut.cpp
@@ -29,7 +29,7 @@ namespace {
         {
             Y_UNUSED(context);
 
-            Cerr << "ListEndpoints: " << request->ShortDebugString() << Endl;
+            std::cerr << "ListEndpoints: " << request->ShortDebugString() << std::endl;
 
             const auto* result = MockResults.FindPtr(request->database());
             Y_ABORT_UNLESS(result, "Mock service doesn't have a result for database '%s'", request->database().c_str());
@@ -54,7 +54,7 @@ namespace {
         {
             Y_UNUSED(context);
 
-            Cerr << "CreateSession: " << request->ShortDebugString() << Endl;
+            std::cerr << "CreateSession: " << request->ShortDebugString() << std::endl;
 
             Ydb::Table::CreateSessionResult result;
             result.set_session_id("my-session-id");
diff --git a/client/ydb_federated_topic/ut/basic_usage_ut.cpp b/client/ydb_federated_topic/ut/basic_usage_ut.cpp
index 77115390441..705a5e0fb79 100644
--- a/client/ydb_federated_topic/ut/basic_usage_ut.cpp
+++ b/client/ydb_federated_topic/ut/basic_usage_ut.cpp
@@ -39,7 +39,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
 
         // Create topic client.
         NYdb::TDriverConfig cfg;
-        cfg.SetEndpoint(TYdbStringBuilder() << "localhost:" << newServicePort);
+        cfg.SetEndpoint(TStringBuilder() << "localhost:" << newServicePort);
         cfg.SetDatabase("/Root");
         cfg.SetLog(CreateLogBackend("cerr", ELogPriority::TLOG_DEBUG));
         NYdb::TDriver driver(cfg);
@@ -53,7 +53,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             .AppendTopics(setup->GetTestTopic());
 
         ReadSession = topicClient.CreateReadSession(readSettings);
-        Cerr << "Session was created" << Endl;
+        std::cerr << "Session was created" << std::endl;
 
         ReadSession->WaitEvent().Wait(TDuration::Seconds(1));
         std::optional<NYdb::NFederatedTopic::TReadSessionEvent::TEvent> event = ReadSession->GetEvent(false);
@@ -98,7 +98,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             ReadSession->WaitEvent().Wait();
             // Get event
             std::optional<NYdb::NFederatedTopic::TReadSessionEvent::TEvent> event = ReadSession->GetEvent(true/*block - will block if no event received yet*/);
-            Cerr << "Got new read session event: " << DebugString(*event) << Endl;
+            std::cerr << "Got new read session event: " << DebugString(*event) << std::endl;
 
             auto* startPartitionSessionEvent = std::get_if<NYdb::NFederatedTopic::TReadSessionEvent::TStartPartitionSessionEvent>(&*event);
             Y_ASSERT(startPartitionSessionEvent);
@@ -135,19 +135,19 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             .MaxMemoryUsageBytes(1_MB)
             .AppendTopics(setup->GetTestTopic());
 
-        Cerr << "Before ReadSession was created" << Endl;
+        std::cerr << "Before ReadSession was created" << std::endl;
         ReadSession = topicClient.CreateReadSession(readSettings);
-        Cerr << "Session was created" << Endl;
+        std::cerr << "Session was created" << std::endl;
 
         auto f = ReadSession->WaitEvent();
-        Cerr << "Returned from WaitEvent" << Endl;
+        std::cerr << "Returned from WaitEvent" << std::endl;
         // observer asyncInit should respect client/session timeouts
         UNIT_ASSERT(!f.Wait(TDuration::Seconds(1)));
 
-        Cerr << "Session blocked successfully" << Endl;
+        std::cerr << "Session blocked successfully" << std::endl;
 
         UNIT_ASSERT(ReadSession->Close(TDuration::MilliSeconds(10)));
-        Cerr << "Session closed gracefully" << Endl;
+        std::cerr << "Session closed gracefully" << std::endl;
     }
 
     Y_UNIT_TEST(RetryDiscoveryWithCancel) {
@@ -231,7 +231,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             .AppendTopics(setup->GetTestTopic());
 
         ReadSession = topicClient.CreateReadSession(readSettings);
-        Cerr << "Session was created" << Endl;
+        std::cerr << "Session was created" << std::endl;
 
         Sleep(TDuration::MilliSeconds(50));
 
@@ -296,7 +296,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             UNIT_ASSERT(!events.empty());
 
             for (auto& e : events) {
-                Cerr << ">>> Got event: " << DebugString(e) << Endl;
+                std::cerr << ">>> Got event: " << DebugString(e) << std::endl;
                 if (auto* dataEvent = std::get_if<TReadSessionEvent::TDataReceivedEvent>(&e)) {
                     dataEvent->Commit();
                 } else if (auto* startPartitionSessionEvent = std::get_if<TReadSessionEvent::TStartPartitionSessionEvent>(&e)) {
@@ -343,7 +343,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             .AppendTopics(setup->GetTestTopic());
 
         ReadSession = topicClient.CreateReadSession(readSettings);
-        Cerr << "Session was created" << Endl;
+        std::cerr << "Session was created" << std::endl;
 
         ReadSession->WaitEvent().Wait(TDuration::Seconds(1));
         auto event = ReadSession->GetEvent(false);
@@ -363,11 +363,11 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
         ReadSession->WaitEvent().Wait();
         event = ReadSession->GetEvent(false);
         UNIT_ASSERT(event.Defined());
-        Cerr << ">>> Got event: " << DebugString(*event) << Endl;
+        std::cerr << ">>> Got event: " << DebugString(*event) << std::endl;
         UNIT_ASSERT(std::holds_alternative<NTopic::TSessionClosedEvent>(*event));
 
         auto ReadSession2 = topicClient.CreateReadSession(readSettings);
-        Cerr << "Session2 was created" << Endl;
+        std::cerr << "Session2 was created" << std::endl;
 
         ReadSession2->WaitEvent().Wait(TDuration::Seconds(1));
         event = ReadSession2->GetEvent(false);
@@ -384,10 +384,10 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
 
         event = ReadSession2->GetEvent(true);
         UNIT_ASSERT(event.Defined());
-        Cerr << ">>> Got event: " << DebugString(*event) << Endl;
+        std::cerr << ">>> Got event: " << DebugString(*event) << std::endl;
         UNIT_ASSERT(std::holds_alternative<TReadSessionEvent::TStartPartitionSessionEvent>(*event));
 
-        // Cerr << ">>> Got event: " << DebugString(*event) << Endl;
+        // std::cerr << ">>> Got event: " << DebugString(*event) << std::endl;
         // UNIT_ASSERT(std::holds_alternative<NTopic::TSessionClosedEvent>(*event));
     }
 
@@ -408,12 +408,12 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             .AppendTopics(setup->GetTestTopic());
 
         ReadSession = topicClient.CreateReadSession(readSettings);
-        Cerr << "Session was created" << Endl;
+        std::cerr << "Session was created" << std::endl;
 
         ReadSession->WaitEvent().Wait(TDuration::Seconds(1));
         std::optional<NYdb::NFederatedTopic::TReadSessionEvent::TEvent> event = ReadSession->GetEvent(false);
         Y_ASSERT(event);
-        Cerr << "Got new read session event: " << DebugString(*event) << Endl;
+        std::cerr << "Got new read session event: " << DebugString(*event) << std::endl;
 
         auto* startPartitionSessionEvent = std::get_if<NYdb::NFederatedTopic::TReadSessionEvent::TStartPartitionSessionEvent>(&*event);
         Y_ASSERT(startPartitionSessionEvent);
@@ -471,7 +471,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             .AppendTopics(setup->GetTestTopic());
 
         readSettings.FederatedEventHandlers_.SimpleDataHandlers([&](TReadSessionEvent::TDataReceivedEvent& ev) mutable {
-            Cerr << ">>> event from dataHandler: " << DebugString(ev) << Endl;
+            std::cerr << ">>> event from dataHandler: " << DebugString(ev) << std::endl;
             Y_VERIFY_S(AtomicGet(check) != 0, "check is false");
             auto& messages = ev.GetMessages();
             for (size_t i = 0u; i < messages.size(); ++i) {
@@ -484,7 +484,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
         });
 
         ReadSession = topicClient.CreateReadSession(readSettings);
-        Cerr << ">>> Session was created" << Endl;
+        std::cerr << ">>> Session was created" << std::endl;
 
         Sleep(TDuration::MilliSeconds(50));
 
@@ -548,12 +548,12 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             .MessageGroupId("src_id");
 
         WriteSession = topicClient.CreateWriteSession(writeSettings);
-        Cerr << "Session was created" << Endl;
+        std::cerr << "Session was created" << std::endl;
 
         WriteSession->WaitEvent().Wait(TDuration::Seconds(1));
         auto event = WriteSession->GetEvent(false);
         Y_ASSERT(event);
-        Cerr << "Got new read session event: " << DebugString(*event) << Endl;
+        std::cerr << "Got new read session event: " << DebugString(*event) << std::endl;
         auto* readyToAcceptEvent = std::get_if<NYdb::NTopic::TWriteSessionEvent::TReadyToAcceptEvent>(&*event);
         Y_ASSERT(readyToAcceptEvent);
         WriteSession->Write(std::move(readyToAcceptEvent->ContinuationToken), NTopic::TWriteMessage("hello"));
@@ -561,7 +561,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
         WriteSession->WaitEvent().Wait(TDuration::Seconds(1));
         event = WriteSession->GetEvent(false);
         Y_ASSERT(event);
-        Cerr << "Got new read session event: " << DebugString(*event) << Endl;
+        std::cerr << "Got new read session event: " << DebugString(*event) << std::endl;
 
         readyToAcceptEvent = std::get_if<NYdb::NTopic::TWriteSessionEvent::TReadyToAcceptEvent>(&*event);
         Y_ASSERT(readyToAcceptEvent);
@@ -579,7 +579,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
         WriteSession->WaitEvent().Wait(TDuration::Seconds(1));
         event = WriteSession->GetEvent(false);
         Y_ASSERT(event);
-        Cerr << "Got new read session event: " << DebugString(*event) << Endl;
+        std::cerr << "Got new read session event: " << DebugString(*event) << std::endl;
 
         auto* acksEvent = std::get_if<NYdb::NTopic::TWriteSessionEvent::TAcksEvent>(&*event);
         Y_ASSERT(acksEvent);
diff --git a/client/ydb_federated_topic/ut/fds_mock.h b/client/ydb_federated_topic/ut/fds_mock.h
index 1ed05a80f11..118d6c5c88b 100644
--- a/client/ydb_federated_topic/ut/fds_mock.h
+++ b/client/ydb_federated_topic/ut/fds_mock.h
@@ -61,7 +61,7 @@ class TFederationDiscoveryServiceMock: public Ydb::FederationDiscovery::V1::Fede
         f.Wait(TDuration::Seconds(35));
         if (f.HasValue()) {
             auto result = f.ExtractValueSync();
-            Cerr << ">>> Ready to answer: " << (result.Status.ok() ? "ok" : "err") << Endl;
+            std::cerr << ">>> Ready to answer: " << (result.Status.ok() ? "ok" : "err") << std::endl;
             *response = std::move(result.Response);
             return result.Status;
         }
diff --git a/client/ydb_persqueue_core/impl/write_session_impl.cpp b/client/ydb_persqueue_core/impl/write_session_impl.cpp
index 65abba46471..3d3aa4b216e 100644
--- a/client/ydb_persqueue_core/impl/write_session_impl.cpp
+++ b/client/ydb_persqueue_core/impl/write_session_impl.cpp
@@ -831,10 +831,10 @@ bool TWriteSessionImpl::CleanupOnAcknowledged(ui64 id) {
     LOG_LAZY(DbDriverState->Log, TLOG_DEBUG, LogPrefix() << "Write session: acknoledged message " << id);
     UpdateTimedCountersImpl();
     if (SentOriginalMessages.empty() || SentOriginalMessages.front().Id != id){
-        Cerr << "State before restart was:\n" << StateStr << "\n\n";
+        std::cerr << "State before restart was:\n" << StateStr << "\n\n";
         DumpState();
-        Cerr << "State on ack with id " << id << " is:\n";
-        Cerr << StateStr << "\n\n";
+        std::cerr << "State on ack with id " << id << " is:\n";
+        std::cerr << StateStr << "\n\n";
         Y_ABORT("got unknown ack");
     }
 
@@ -1098,9 +1098,9 @@ bool TWriteSessionImpl::IsReadyToSendNextImpl() {
     Y_ABORT_UNLESS(!OriginalMessagesToSend.empty(), "There are packed messages but no original messages");
     if (OriginalMessagesToSend.front().Id > PackedMessagesToSend.top().Offset) {
 
-        Cerr << " State before restart was:\n" << StateStr << "\n\n";
+        std::cerr << " State before restart was:\n" << StateStr << "\n\n";
         DumpState();
-        Cerr << " State after restart is:\n" << StateStr << "\n\n";
+        std::cerr << " State after restart is:\n" << StateStr << "\n\n";
         Y_ABORT("Lost original message(s)");
     }
 
diff --git a/client/ydb_persqueue_core/ut/basic_usage_ut.cpp b/client/ydb_persqueue_core/ut/basic_usage_ut.cpp
index b62790a701f..b4586b99dbd 100644
--- a/client/ydb_persqueue_core/ut/basic_usage_ut.cpp
+++ b/client/ydb_persqueue_core/ut/basic_usage_ut.cpp
@@ -68,7 +68,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
         ui32 previousOffset = 0;
         bool closed = false;
         while ((readMessageCount < messageCount || committedOffset <= previousOffset) && !closed) {
-            Cerr << "Get event on client\n";
+            std::cerr << "Get event on client\n";
             auto event = *readSession->GetEvent(true);
             std::visit(TOverloaded {
                 [&](TReadSessionEvent::TDataReceivedEvent& event) {
@@ -149,7 +149,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             auto sessionAdapter = TSimpleWriteSessionTestAdapter(
                     dynamic_cast<TSimpleBlockingWriteSession *>(session.get()));
             if (shouldCaptureData.has_value()) {
-                TYdbStringBuilder msg;
+                TStringBuilder msg;
                 msg << "Session has captured " << sessionAdapter.GetAcquiredMessagesCount()
                     << " messages, capturing was expected: " << *shouldCaptureData << Endl;
                 UNIT_ASSERT_VALUES_EQUAL_C(sessionAdapter.GetAcquiredMessagesCount() > 0, *shouldCaptureData, msg.c_str());
@@ -329,7 +329,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             oss << message;
         }
 
-        Cerr << message << " " << packed << "\n";
+        std::cerr << message << " " << packed << "\n";
 
         {
             auto event = *writer->GetEvent(true);
@@ -364,7 +364,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
                 }
                 ++tokens;
             }
-            Cerr << "GOT EVENT " << acks << " " << tokens << "\n";
+            std::cerr << "GOT EVENT " << acks << " " << tokens << "\n";
 
         }
         UNIT_ASSERT(!writer->WaitEvent().Wait(TDuration::Seconds(5)));
@@ -377,7 +377,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
         );
         ui32 readMessageCount = 0;
         while (readMessageCount < 4) {
-            Cerr << "Get event on client\n";
+            std::cerr << "Get event on client\n";
             auto event = *readSession->GetEvent(true);
             std::visit(TOverloaded {
                 [&](TReadSessionEvent::TDataReceivedEvent& event) {
@@ -481,7 +481,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
                 .RetryPolicy(IRetryPolicy::GetNoRetryPolicy());
         std::shared_ptr<IReadSession> readSession = client.CreateReadSession(settings);
 
-        Cerr << "Get event on client\n";
+        std::cerr << "Get event on client\n";
         auto event = *readSession->GetEvent(true);
         std::visit(TOverloaded {
                 [&](TReadSessionEvent::TDataReceivedEvent&) {
@@ -505,7 +505,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
                     UNIT_FAIL("Test does not support lock sessions yet");
                 },
                 [&](TSessionClosedEvent& event) {
-                    Cerr << "Got close event: " << event.DebugString();
+                    std::cerr << "Got close event: " << event.DebugString();
                 }
 
             }, event);
diff --git a/client/ydb_persqueue_core/ut/compress_executor_ut.cpp b/client/ydb_persqueue_core/ut/compress_executor_ut.cpp
index da4bcde9c72..c79d2b7daa7 100644
--- a/client/ydb_persqueue_core/ut/compress_executor_ut.cpp
+++ b/client/ydb_persqueue_core/ut/compress_executor_ut.cpp
@@ -18,7 +18,7 @@ Y_UNIT_TEST_SUITE(CompressExecutor) {
         UNIT_ASSERT(!f1.HasValue());
         UNIT_ASSERT(!f2.HasValue());
         queue->Enqueue(1);
-        Cerr << "Waiting for writes to complete.\n";
+        std::cerr << "Waiting for writes to complete.\n";
         f1.Wait();
         f2.Wait();
 
@@ -49,7 +49,7 @@ Y_UNIT_TEST_SUITE(CompressExecutor) {
                 Y_ABORT("ANother ready to accept!");
             }
             if(std::holds_alternative<TSessionClosedEvent>(event)) {
-                Cerr << "Session closed: " << std::get<TSessionClosedEvent>(event).DebugString() << "\n";
+                std::cerr << "Session closed: " << std::get<TSessionClosedEvent>(event).DebugString() << "\n";
                 Y_ABORT("");
             }
         }
@@ -77,7 +77,7 @@ Y_UNIT_TEST_SUITE(CompressExecutor) {
         event = *writer->GetEvent(true);
         UNIT_ASSERT(std::holds_alternative<TWriteSessionEvent::TAcksEvent>(event));
 
-        Cerr << "===Will now kick tablets\n";
+        std::cerr << "===Will now kick tablets\n";
         setup->KickTablets();
         retryPolicy->ExpectBreakDown();
         retryPolicy->WaitForRetriesSync(1);
@@ -92,7 +92,7 @@ Y_UNIT_TEST_SUITE(CompressExecutor) {
                 continueToken = std::move(std::get<TWriteSessionEvent::TReadyToAcceptEvent>(event).ContinuationToken);
             }
         }
-        Cerr << "============ UT - Wait event...\n";
+        std::cerr << "============ UT - Wait event...\n";
         waitEventFuture = writer->WaitEvent();
         waitEventFuture.Wait(TDuration::Seconds(3));
         UNIT_ASSERT(!waitEventFuture.HasValue());
diff --git a/client/ydb_persqueue_core/ut/compression_ut.cpp b/client/ydb_persqueue_core/ut/compression_ut.cpp
index 834498bba51..cab143c39a8 100644
--- a/client/ydb_persqueue_core/ut/compression_ut.cpp
+++ b/client/ydb_persqueue_core/ut/compression_ut.cpp
@@ -55,7 +55,7 @@ Y_UNIT_TEST_SUITE(Compression) {
         UNIT_ASSERT(status.ok());
         Ydb::PersQueue::V1::AlterTopicResult result;
         response.operation().result().UnpackTo(&result);
-        Cerr << "Alter topic response: " << response << "\nAlter result: " << result << "\n";
+        std::cerr << "Alter topic response: " << response << "\nAlter result: " << result << "\n";
         UNIT_ASSERT_VALUES_EQUAL(response.operation().status(), Ydb::StatusIds::SUCCESS);
     }
 
@@ -78,14 +78,14 @@ Y_UNIT_TEST_SUITE(Compression) {
         const std::vector<ECodec> codecs,
         bool decompress
     ) {
-        Cerr << Endl << "Start read" << Endl << Endl;
+        std::cerr << std::endl << "Start read" << std::endl << std::endl;
         auto readSettings = setup.GetReadSessionSettings();
         readSettings.Decompress(decompress);
         NThreading::TPromise<void> checkedPromise = NThreading::NewPromise<void>();
         auto totalReceived = 0u;
         readSettings.EventHandlers_.SimpleDataHandlers(
             [&](const NYdb::NPersQueue::TReadSessionEvent::TDataReceivedEvent& ev) {
-                Cerr << Endl << Endl << Endl << "Got messages" << Endl << Endl;
+                std::cerr << std::endl << std::endl << std::endl << "Got messages" << std::endl << std::endl;
                 if (decompress) {
                     UNIT_ASSERT_NO_EXCEPTION(ev.GetMessages());
                     UNIT_ASSERT_EXCEPTION(ev.GetCompressedMessages(), yexception);
@@ -102,7 +102,7 @@ Y_UNIT_TEST_SUITE(Compression) {
                         ++totalReceived;
                     }
                 }
-                Cerr << Endl << "totalReceived: " << totalReceived << " wait: " << messages.size() << Endl << Endl;
+                std::cerr << std::endl << "totalReceived: " << totalReceived << " wait: " << messages.size() << std::endl << std::endl;
                 if (totalReceived == messages.size())
                     checkedPromise.SetValue();
             }
diff --git a/client/ydb_persqueue_core/ut/read_session_ut.cpp b/client/ydb_persqueue_core/ut/read_session_ut.cpp
index 0d681aa6b51..8117e7e7114 100644
--- a/client/ydb_persqueue_core/ut/read_session_ut.cpp
+++ b/client/ydb_persqueue_core/ut/read_session_ut.cpp
@@ -526,7 +526,7 @@ class TReorderingExecutor : public ::IExecutor {
     void Post(TFunction&& f) override {
         {
             std::lock_guard guard(Lock);
-            Cerr << "Post function" << Endl;
+            std::cerr << "Post function" << std::endl;
             ++TasksAdded;
             if (Functions.empty()) {
                 Functions.reserve(CycleCount);
@@ -686,7 +686,7 @@ Y_UNIT_TEST_SUITE(PersQueueSdkReadSessionTest) {
             UNIT_ASSERT(event);
             UNIT_ASSERT_EVENT_TYPE(*event, TReadSessionEvent::TCreatePartitionStreamEvent);
             std::get<TReadSessionEvent::TCreatePartitionStreamEvent>(*event).Confirm();
-            Cerr << "create event " << DebugString(*event) << Endl;
+            std::cerr << "create event " << DebugString(*event) << std::endl;
         }
         // Event 2: data.
         {
@@ -698,7 +698,7 @@ Y_UNIT_TEST_SUITE(PersQueueSdkReadSessionTest) {
             for (auto& msg : dataEvent.GetMessages()) {
                 UNIT_ASSERT(msg.GetData() == "message1" || msg.GetData() == "message2");
             }
-            Cerr << "data event " << DebugString(*event) << Endl;
+            std::cerr << "data event " << DebugString(*event) << std::endl;
             if (commit) {
                 dc.Add(dataEvent);
             }
@@ -714,7 +714,7 @@ Y_UNIT_TEST_SUITE(PersQueueSdkReadSessionTest) {
             for (auto& msg : dataEvent.GetMessages()) {
                 UNIT_ASSERT(msg.GetData() == "message3");
             }
-            Cerr << "data event " << DebugString(*event) << Endl;
+            std::cerr << "data event " << DebugString(*event) << std::endl;
 
             dataEvent.Commit(); // Commit right now!
         }
@@ -729,14 +729,14 @@ Y_UNIT_TEST_SUITE(PersQueueSdkReadSessionTest) {
         if (commit) {  // (commit && close) branch check is broken with current TReadSession::Close quick fix
             std::optional<TReadSessionEvent::TEvent> event = session->GetEvent(!close); // Event is expected to be already in queue if closed.
             UNIT_ASSERT(event);
-            Cerr << "commit ack or close event " << DebugString(*event) << Endl;
+            std::cerr << "commit ack or close event " << DebugString(*event) << std::endl;
             UNIT_ASSERT(std::holds_alternative<TReadSessionEvent::TCommitAcknowledgementEvent>(*event) || std::holds_alternative<TSessionClosedEvent>(*event));
         }
 
         if (close && !commit) {
             std::optional<TReadSessionEvent::TEvent> event = session->GetEvent(false);
             UNIT_ASSERT(event);
-            Cerr << "close event " << DebugString(*event) << Endl;
+            std::cerr << "close event " << DebugString(*event) << std::endl;
             UNIT_ASSERT(std::holds_alternative<TSessionClosedEvent>(*event));
             UNIT_ASSERT_STRING_CONTAINS(DebugString(*event), "Session was gracefully closed");
         }
@@ -769,7 +769,7 @@ Y_UNIT_TEST_SUITE(PersQueueSdkReadSessionTest) {
         std::optional<TReadSessionEvent::TEvent> event =                \
             session->GetEvent(true);                                    \
         UNIT_ASSERT(event);                                             \
-        Cerr << DebugString(*event) << Endl;                            \
+        std::cerr << DebugString(*event) << std::endl;                            \
         UNIT_ASSERT_EVENT_TYPE(*event, TSessionClosedEvent);            \
         /**/
 
@@ -805,7 +805,7 @@ Y_UNIT_TEST_SUITE(PersQueueSdkReadSessionTest) {
         std::shared_ptr<IReadSession> session = setup.GetPersQueueClient().CreateReadSession(settings);
         std::optional<TReadSessionEvent::TEvent> event = session->GetEvent(true);
         UNIT_ASSERT(event);
-        Cerr << DebugString(*event) << Endl;
+        std::cerr << DebugString(*event) << std::endl;
         UNIT_ASSERT_EVENT_TYPE(*event, TSessionClosedEvent);
     }
 
@@ -820,7 +820,7 @@ Y_UNIT_TEST_SUITE(PersQueueSdkReadSessionTest) {
             std::shared_ptr<IReadSession> session = setup.GetPersQueueClient().CreateReadSession(settings);
             std::optional<TReadSessionEvent::TEvent> event = session->GetEvent(true);
             UNIT_ASSERT(event);
-            Cerr << DebugString(*event) << Endl;
+            std::cerr << DebugString(*event) << std::endl;
             UNIT_ASSERT_NOT_EVENT_TYPE(*event, TSessionClosedEvent);
         }
 
@@ -830,7 +830,7 @@ Y_UNIT_TEST_SUITE(PersQueueSdkReadSessionTest) {
             std::shared_ptr<IReadSession> session = setup.GetPersQueueClient().CreateReadSession(settings);
             std::optional<TReadSessionEvent::TEvent> event = session->GetEvent(true);
             UNIT_ASSERT(event);
-            Cerr << DebugString(*event) << Endl;
+            std::cerr << DebugString(*event) << std::endl;
             UNIT_ASSERT_EVENT_TYPE(*event, TSessionClosedEvent);
         }
 
@@ -840,7 +840,7 @@ Y_UNIT_TEST_SUITE(PersQueueSdkReadSessionTest) {
             std::shared_ptr<IReadSession> session = setup.GetPersQueueClient().CreateReadSession(settings);
             std::optional<TReadSessionEvent::TEvent> event = session->GetEvent(true);
             UNIT_ASSERT(event);
-            Cerr << DebugString(*event) << Endl;
+            std::cerr << DebugString(*event) << std::endl;
             UNIT_ASSERT_EVENT_TYPE(*event, TSessionClosedEvent);
         }
     }
@@ -856,7 +856,7 @@ Y_UNIT_TEST_SUITE(PersQueueSdkReadSessionTest) {
             UNIT_ASSERT(event);
             UNIT_ASSERT_EVENT_TYPE(*event, TReadSessionEvent::TCreatePartitionStreamEvent);
             std::get<TReadSessionEvent::TCreatePartitionStreamEvent>(*event).Confirm();
-            Cerr << DebugString(*event) << Endl;
+            std::cerr << DebugString(*event) << std::endl;
         }
 
         // Event 2: receive data.
@@ -867,7 +867,7 @@ Y_UNIT_TEST_SUITE(PersQueueSdkReadSessionTest) {
             TReadSessionEvent::TDataReceivedEvent& dataEvent = std::get<TReadSessionEvent::TDataReceivedEvent>(*event);
             UNIT_ASSERT_VALUES_EQUAL(dataEvent.GetMessages().size(), 1);
             UNIT_ASSERT_VALUES_EQUAL(dataEvent.GetMessages()[0].GetData(), content);
-            Cerr << DebugString(*event) << Endl;
+            std::cerr << DebugString(*event) << std::endl;
             return event;
         };
 
@@ -893,7 +893,7 @@ Y_UNIT_TEST_SUITE(PersQueueSdkReadSessionTest) {
             std::optional<TReadSessionEvent::TEvent> event = session->GetEvent(true);
             UNIT_ASSERT(event);
             Y_ASSERT(std::holds_alternative<TReadSessionEvent::TCommitAcknowledgementEvent>(*event));
-            Cerr << DebugString(*event) << Endl;
+            std::cerr << DebugString(*event) << std::endl;
         }
 
         auto eventFuture = session->WaitEvent();
@@ -1221,7 +1221,7 @@ Y_UNIT_TEST_SUITE(ReadSessionImplTest) {
             UNIT_ASSERT(event);
             UNIT_ASSERT_EVENT_TYPE(*event, TReadSessionEvent::TDataReceivedEvent);
             auto& dataEvent = std::get<TReadSessionEvent::TDataReceivedEvent>(*event);
-            Cerr << dataEvent.DebugString() << "\n";
+            std::cerr << dataEvent.DebugString() << "\n";
             UNIT_ASSERT_VALUES_EQUAL(dataEvent.GetMessages().size(), 3);
             UNIT_ASSERT_EXCEPTION(dataEvent.GetMessages()[0].GetData(), TZLibDecompressorError);
             UNIT_ASSERT_VALUES_EQUAL(dataEvent.GetMessages()[1].GetData(), "message2");
@@ -1316,8 +1316,8 @@ Y_UNIT_TEST_SUITE(ReadSessionImplTest) {
 
         const std::string messageData = GenerateMessageData(messageSize);
         const std::string compressedMessageData = Compress(messageData);
-        Cerr << "Message data size: " << messageData.size() << Endl;
-        Cerr << "Compressed message data size: " << compressedMessageData.size() << Endl;
+        std::cerr << "Message data size: " << messageData.size() << std::endl;
+        std::cerr << "Compressed message data size: " << compressedMessageData.size() << std::endl;
         ui64 offset = 1;
         ui64 seqNo = 42;
         THashSet<ui64> committedCookies;
@@ -1328,7 +1328,7 @@ Y_UNIT_TEST_SUITE(ReadSessionImplTest) {
                     committedCookies.insert(commit.partition_cookie());
                 }
                 for (const auto& range : req.offset_ranges()) {
-                    Cerr << "GOT RANGE " << range.start_offset() << " " << range.end_offset() << "\n";
+                    std::cerr << "GOT RANGE " << range.start_offset() << " " << range.end_offset() << "\n";
                     for (ui64 i = range.start_offset(); i < range.end_offset(); ++i) {
                         committedOffsets.insert(i);
                     }
@@ -1350,11 +1350,11 @@ Y_UNIT_TEST_SUITE(ReadSessionImplTest) {
         ui64 prevOffset = 0;
         ui64 prevSeqNo = 41;
         for (size_t i = 0; i < batches; ++i) {
-            Cerr << "Getting new event" << Endl;
+            std::cerr << "Getting new event" << std::endl;
             std::optional<TReadSessionEvent::TEvent> event = setup.EventsQueue->GetEvent(true, batchLimit);
             UNIT_ASSERT(event);
             UNIT_ASSERT_EVENT_TYPE(*event, TReadSessionEvent::TDataReceivedEvent);
-            Cerr << DebugString(*event) << Endl;
+            std::cerr << DebugString(*event) << std::endl;
             auto& dataEvent = std::get<TReadSessionEvent::TDataReceivedEvent>(*event);
             UNIT_ASSERT_VALUES_EQUAL(dataEvent.GetMessages().size(), messagesInBatch);
             for (const auto& message : dataEvent.GetMessages()) {
@@ -1563,7 +1563,7 @@ Y_UNIT_TEST_SUITE(ReadSessionImplTest) {
         bool has2 = false;
         EXPECT_CALL(*setup.MockProcessor, OnCommitRequest(_))
             .WillRepeatedly(Invoke([&](const Ydb::PersQueue::V1::MigrationStreamingReadClientMessage::Commit& req) {
-                Cerr << "Got commit req " << req << "\n";
+                std::cerr << "Got commit req " << req << "\n";
                 for (const auto& commit : req.cookies()) {
                     if (commit.partition_cookie() == 1) {
                         has1 = true;
@@ -1574,7 +1574,7 @@ Y_UNIT_TEST_SUITE(ReadSessionImplTest) {
                     }
                 }
                 for (const auto& range : req.offset_ranges()) {
-                    Cerr << "RANGE " << range.start_offset() << " " << range.end_offset() << "\n";
+                    std::cerr << "RANGE " << range.start_offset() << " " << range.end_offset() << "\n";
                     if (range.start_offset() == 10 && range.end_offset() == 12) has1 = true;
                     else if (range.start_offset() == 0 && range.end_offset() == 10) has2 = true;
                     else UNIT_ASSERT(false);
@@ -1586,7 +1586,7 @@ Y_UNIT_TEST_SUITE(ReadSessionImplTest) {
             UNIT_ASSERT(event);
             UNIT_ASSERT_EVENT_TYPE(*event, TReadSessionEvent::TDataReceivedEvent);
             TReadSessionEvent::TDataReceivedEvent& dataEvent = std::get<TReadSessionEvent::TDataReceivedEvent>(*event);
-            Cerr << "got data event: " << dataEvent.DebugString() << "\n";
+            std::cerr << "got data event: " << dataEvent.DebugString() << "\n";
             dataEvent.Commit();
 
             i += dataEvent.GetMessagesCount();
@@ -1628,7 +1628,7 @@ Y_UNIT_TEST_SUITE(ReadSessionImplTest) {
         settings.EventHandlers_.SimpleDataHandlers([&](TReadSessionEvent::TDataReceivedEvent& event) {
             for (auto& message: event.GetMessages()) {
                 ++time;
-                Cerr << "GOT MESSAGE: " << message.DebugString(true) << "\n";
+                std::cerr << "GOT MESSAGE: " << message.DebugString(true) << "\n";
                 UNIT_ASSERT_VALUES_EQUAL(message.GetData(), TYdbStringBuilder() << "message" << time);
                 if (time == 3) {
                     calledPromise.SetValue();
diff --git a/client/ydb_persqueue_core/ut/retry_policy_ut.cpp b/client/ydb_persqueue_core/ut/retry_policy_ut.cpp
index 58cb669963b..3c5251dd5e4 100644
--- a/client/ydb_persqueue_core/ut/retry_policy_ut.cpp
+++ b/client/ydb_persqueue_core/ut/retry_policy_ut.cpp
@@ -19,9 +19,9 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
         auto doBreakDown = [&] () {
             helper.Policy->ExpectBreakDown();
             NThreading::TPromise<void> retriesPromise = NThreading::NewPromise();
-            Cerr << "WAIT for retries...\n";
+            std::cerr << "WAIT for retries...\n";
             helper.Policy->WaitForRetries(30, retriesPromise);
-            Cerr << "KICK tablets\n";
+            std::cerr << "KICK tablets\n";
             helper.Setup->KickTablets();
 
             auto f1 = helper.Write(false);
@@ -29,19 +29,19 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
 
             auto retriesFuture = retriesPromise.GetFuture();
             retriesFuture.Wait();
-            Cerr << "WAIT for retries done\n";
+            std::cerr << "WAIT for retries done\n";
 
             NThreading::TPromise<void> repairPromise = NThreading::NewPromise();
             auto repairFuture = repairPromise.GetFuture();
             helper.Policy->WaitForRepair(repairPromise);
 
 
-            Cerr << "ALLOW tablets\n";
+            std::cerr << "ALLOW tablets\n";
             helper.Setup->AllowTablets();
 
-            Cerr << "WAIT for repair\n";
+            std::cerr << "WAIT for repair\n";
             repairFuture.Wait();
-            Cerr << "REPAIR done\n";
+            std::cerr << "REPAIR done\n";
             f1.Wait();
             f2.Wait();
             helper.Write(true);
@@ -82,29 +82,29 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
         retryPolicy->ExpectBreakDown();
 
         auto& client = setup1->GetPersQueueClient();
-        Cerr << "=== Create write session \n";
+        std::cerr << "=== Create write session \n";
         auto writer = client.CreateWriteSession(settings);
 
         NThreading::TPromise<void> retriesPromise = NThreading::NewPromise();
         auto retriesFuture = retriesPromise.GetFuture();
         retryPolicy->WaitForRetries(3, retriesPromise);
-        Cerr << "=== Wait retries\n";
+        std::cerr << "=== Wait retries\n";
         retriesFuture.Wait();
 
-        Cerr << "=== Enable dc2\n";
+        std::cerr << "=== Enable dc2\n";
         setup1->EnableDataCenter("dc2");
 
         NThreading::TPromise<void> repairPromise = NThreading::NewPromise();
         auto repairFuture = repairPromise.GetFuture();
         retryPolicy->WaitForRepair(repairPromise);
-        Cerr << "=== Wait for repair\n";
+        std::cerr << "=== Wait for repair\n";
         repairFuture.Wait();
-        Cerr << "=== Close writer\n";
+        std::cerr << "=== Close writer\n";
         writer->Close();
     }
 
     Y_UNIT_TEST(TWriteSession_SwitchBackToLocalCluster) {
-        Cerr << "====Start test\n";
+        std::cerr << "====Start test\n";
 
         auto setup1 = std::make_shared<TPersQueueYdbSdkTestSetup>(TEST_CASE_NAME, false);
         SDKTestSetup setup2("SwitchBackToLocalCluster", false);
@@ -113,14 +113,14 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
         setup1->AddDataCenter("dc2", setup2, true);
         setup1->Start();
         setup2.Start(false);
-        Cerr << "=== Start session 1\n";
+        std::cerr << "=== Start session 1\n";
         auto helper = MakeHolder<TYdbPqWriterTestHelper>("", nullptr, std::string(), setup1);
         helper->Write(true);
         auto retryPolicy = helper->Policy;
         retryPolicy->Initialize();
 
         auto waitForReconnect = [&](bool enable) {
-            Cerr << "=== Expect breakdown\n";
+            std::cerr << "=== Expect breakdown\n";
             retryPolicy->ExpectBreakDown();
 
             NThreading::TPromise<void> retriesPromise = NThreading::NewPromise();
@@ -132,11 +132,11 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
             retryPolicy->WaitForRepair(repairPromise);
 
             if (enable) {
-                Cerr << "===Enabled DC1\n";
+                std::cerr << "===Enabled DC1\n";
                 setup1->EnableDataCenter("dc1");
                 setup2.EnableDataCenter("dc1");
             } else {
-                Cerr << "===Disabled DC1\n";
+                std::cerr << "===Disabled DC1\n";
                 setup1->DisableDataCenter("dc1");
                 setup2.DisableDataCenter("dc1");
             }
@@ -145,9 +145,9 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
             retriesFuture.Wait();
             repairFuture.Wait();
         };
-        Cerr << "===Wait for 1st reconnect\n";
+        std::cerr << "===Wait for 1st reconnect\n";
         waitForReconnect(false);
-        Cerr << "===Wait for 2nd reconnect\n";
+        std::cerr << "===Wait for 2nd reconnect\n";
         waitForReconnect(true);
     }
 
@@ -169,14 +169,14 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
         auto& client = setup1->GetPersQueueClient();
 
         //! Fill data in dc1 1 with SeqNo = 1..10 for 2 different SrcId
-        Cerr << "===Write 10 messages into every writer\n";
+        std::cerr << "===Write 10 messages into every writer\n";
         for (auto i = 0; i != 10; i++) {
             writer1->Write(true); // 1
             writer2->Write(true); // 1
         }
-        Cerr << "===Messages were written\n";
+        std::cerr << "===Messages were written\n";
 
-        Cerr << "===Disable dc1\n";
+        std::cerr << "===Disable dc1\n";
         //! Leave only dc2 available
         writer1->Policy->ExpectBreakDown();
         writer2->Policy->ExpectBreakDown();
@@ -184,17 +184,17 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
         writer1->Policy->WaitForRetriesSync(1);
         writer2->Policy->WaitForRetriesSync(1);
 
-        Cerr << "===Recreate writers\n";
+        std::cerr << "===Recreate writers\n";
 
         //! Re-create writers, kill previous sessions. New sessions will connect to dc2.
         writer1 = MakeHolder<TYdbPqWriterTestHelper>("", nullptr, std::string(), setup1, sourceId1, true);
         writer2 = MakeHolder<TYdbPqWriterTestHelper>("", nullptr, std::string(), setup1, sourceId2, true);
 
         //! Write some data and await confirmation - just to ensure sessions are started.
-        Cerr << "===Write one message into every writer\n";
+        std::cerr << "===Write one message into every writer\n";
         writer1->Write(true);
         writer2->Write(true);
-        Cerr << "===Messages were written\n";
+        std::cerr << "===Messages were written\n";
 
         //! Leave no available DCs
         writer1->Policy->ExpectBreakDown();
@@ -202,14 +202,14 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
         writer1->Policy->Initialize();
         writer2->Policy->Initialize();
 
-        Cerr << "===Disable dc2\n";
+        std::cerr << "===Disable dc2\n";
         setup1->DisableDataCenter("dc2");
-        Cerr << "===Wait for retries after initial dc2 shutdown\n";
+        std::cerr << "===Wait for retries after initial dc2 shutdown\n";
         writer1->Policy->WaitForRetriesSync(1);
         writer2->Policy->WaitForRetriesSync(1);
 
         //! Put some data inflight. It cannot be written now, but SeqNo will be assigned.
-        Cerr << "===Write four async message into every writer\n";
+        std::cerr << "===Write four async message into every writer\n";
         for (auto i = 0; i != 3; i++) {
             writer1->Write(false);
             writer2->Write(false);
@@ -220,46 +220,46 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
         //! Enable DC1. Now writers gonna write collected data to DC1 having LastSeqNo = 10
         //! (because of data written in the very beginning), and inflight data has SeqNo assigned = 2..5,
         //! so the SeqNo shift takes place.
-        Cerr << "===Enable dc2\n";
+        std::cerr << "===Enable dc2\n";
         setup1->EnableDataCenter("dc1");
 
-        Cerr << "===Wait for writes to complete\n";
+        std::cerr << "===Wait for writes to complete\n";
         f1.Wait();
         f2.Wait();
-        Cerr << "===Messages were written\n";
+        std::cerr << "===Messages were written\n";
 
         //! Writer1 is not used any more.
         writer1->EventLoop->AllowStop();
         writer1 = nullptr;
 
-        Cerr << "===Writer 1 closed\n";
+        std::cerr << "===Writer 1 closed\n";
         writer2->Policy->ExpectBreakDown();
         writer2->Policy->Initialize();
 
         //! For the second writer, do switchback to dc2.
-        Cerr << "===Disable dc1\n";
+        std::cerr << "===Disable dc1\n";
         setup1->DisableDataCenter("dc1");
-        Cerr << "===Wait for retries after dc1 shutdown\n";
+        std::cerr << "===Wait for retries after dc1 shutdown\n";
         writer2->Policy->WaitForRetriesSync(1);
 
         //! Put some data inflight again;
-        Cerr << "===Write four async messages into writer2\n";
+        std::cerr << "===Write four async messages into writer2\n";
         for (auto i = 0; i != 3; i++) {
             writer2->Write(false);
         }
         f2 = writer2->Write(false);
 
-        Cerr << "===Enable dc2\n";
+        std::cerr << "===Enable dc2\n";
         setup1->EnableDataCenter("dc2");
 
         f2.Wait();
-        Cerr << "===Messages were written\n";
+        std::cerr << "===Messages were written\n";
 
         writer2->EventLoop->AllowStop();
         writer2->Policy->ExpectBreakDown();
         writer2 = nullptr;
 
-        Cerr << "===Enable dc1\n";
+        std::cerr << "===Enable dc1\n";
         setup1->EnableDataCenter("dc1");
         auto CheckSeqNo = [&] (const std::string& dcName, ui64 expectedSeqNo) {
             settings.PreferredCluster(dcName);
@@ -274,17 +274,17 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
         //!check SeqNo in both DC. For writer1 We expect 14 messages in DC1
         //! (10 written initially + 4 written after reconnect) and 1 message in DC2 (only initial message).
         settings.MessageGroupId(sourceId1);
-        Cerr << "===Check SeqNo writer1, dc2\n";
+        std::cerr << "===Check SeqNo writer1, dc2\n";
         CheckSeqNo("dc2", 1);
-        Cerr << "===Check SeqNo writer1, dc1\n";
+        std::cerr << "===Check SeqNo writer1, dc1\n";
         CheckSeqNo("dc1", 14);
 
         //! Check SeqNo for writer 2; Expect to have 6 messages on DC2 with MaxSeqNo = 6;
         settings.MessageGroupId(sourceId2);
-        Cerr << "===Check SeqNo writer2 dc1\n";
+        std::cerr << "===Check SeqNo writer2 dc1\n";
         CheckSeqNo("dc1", 14);
         //! DC2 has no shift in SeqNo since 5 messages were written to dc 1.
-        Cerr << "===Check SeqNo writer2 dc2\n";
+        std::cerr << "===Check SeqNo writer2 dc2\n";
         CheckSeqNo("dc2", 9);
 
 
@@ -309,11 +309,11 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
         ui32 clustersPendingSrc2 = 2;
 
         while (!stop && (clustersPendingSrc2 || clustersPendingSrc1)) {
-            Cerr << "===Get event on client\n";
+            std::cerr << "===Get event on client\n";
             auto event = *readSession->GetEvent(true);
             std::visit(TOverloaded {
                     [&](TReadSessionEvent::TDataReceivedEvent& event) {
-                        Cerr << "===Data event\n";
+                        std::cerr << "===Data event\n";
                         auto& clusterName = event.GetPartitionStream()->GetCluster();
                         for (auto& message: event.GetMessages()) {
                             std::string sourceId = message.GetMessageGroupId();
@@ -361,15 +361,15 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
                         event.Confirm();
                     },
                     [&](TReadSessionEvent::TPartitionStreamStatusEvent&) {
-                        Cerr << "===Status event\n";
+                        std::cerr << "===Status event\n";
                         UNIT_FAIL("Test does not support lock sessions yet");
                     },
                     [&](TReadSessionEvent::TPartitionStreamClosedEvent&) {
-                        Cerr << "===Stream closed event\n";
+                        std::cerr << "===Stream closed event\n";
                         UNIT_FAIL("Test does not support lock sessions yet");
                     },
                     [&](TSessionClosedEvent& event) {
-                        Cerr << "===Got close event: " << event.DebugString();
+                        std::cerr << "===Got close event: " << event.DebugString();
                         stop = true;
                     }
 
@@ -387,7 +387,7 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
         auto& client = setup->GetPersQueueClient();
         auto writer = client.CreateWriteSession(settings);
         auto event = *writer->GetEvent(true);
-        Cerr << NYdb::NPersQueue::DebugString(event) << "\n";
+        std::cerr << NYdb::NPersQueue::DebugString(event) << "\n";
         UNIT_ASSERT(std::holds_alternative<TWriteSessionEvent::TReadyToAcceptEvent>(event));
         auto continueToken = std::move(std::get<TWriteSessionEvent::TReadyToAcceptEvent>(event).ContinuationToken);
         std::string message = "1234567890";
@@ -398,7 +398,7 @@ Y_UNIT_TEST_SUITE(RetryPolicy) {
         retryPolicy->WaitForRetriesSync(3);
         while (seqNo < 10) {
             auto event = *writer->GetEvent(true);
-            Cerr << NYdb::NPersQueue::DebugString(event) << "\n";
+            std::cerr << NYdb::NPersQueue::DebugString(event) << "\n";
             UNIT_ASSERT(std::holds_alternative<TWriteSessionEvent::TReadyToAcceptEvent>(event));
             writer->Write(
                     std::move(std::get<TWriteSessionEvent::TReadyToAcceptEvent>(event).ContinuationToken),
diff --git a/client/ydb_persqueue_core/ut/ut_utils/sdk_test_setup.h b/client/ydb_persqueue_core/ut/ut_utils/sdk_test_setup.h
index eea12bc8475..d1872b9089e 100644
--- a/client/ydb_persqueue_core/ut/ut_utils/sdk_test_setup.h
+++ b/client/ydb_persqueue_core/ut/ut_utils/sdk_test_setup.h
@@ -37,7 +37,7 @@ class SDKTestSetup {
 
     void InitOptions(ui32 nodeCount = NKikimr::NPersQueueTests::PQ_DEFAULT_NODE_COUNT) {
         Log.SetFormatter([testCaseName = TestCaseName](ELogPriority priority, std::string_view message) {
-            return TYdbStringBuilder() << TInstant::Now() << " :" << testCaseName << " " << priority << ": " << message << Endl;
+            return TStringBuilder() << TInstant::Now() << " :" << testCaseName << " " << priority << ": " << message << Endl;
         });
         Server.ServerSettings.SetNodeCount(nodeCount);
         Server.GrpcServerOptions.SetGRpcShutdownDeadline(TDuration::Max());
diff --git a/client/ydb_persqueue_core/ut/ut_utils/test_server.h b/client/ydb_persqueue_core/ut/ut_utils/test_server.h
index f42cfc6945c..df6041e8961 100644
--- a/client/ydb_persqueue_core/ut/ut_utils/test_server.h
+++ b/client/ydb_persqueue_core/ut/ut_utils/test_server.h
@@ -46,7 +46,7 @@ class TTestServer {
 
     void StartServer(bool doClientInit = true, std::optional<std::string> databaseName = std::nullopt) {
         Log.SetFormatter([](ELogPriority priority, std::string_view message) {
-            return TYdbStringBuilder() << TInstant::Now() << " " << priority << ": " << message << Endl;
+            return TStringBuilder() << TInstant::Now() << " " << priority << ": " << message << Endl;
         });
 
         PrepareNetDataFile();
diff --git a/client/ydb_persqueue_core/ut/ut_utils/ut_utils.h b/client/ydb_persqueue_core/ut/ut_utils/ut_utils.h
index b4e2f47182b..54210b80b00 100644
--- a/client/ydb_persqueue_core/ut/ut_utils/ut_utils.h
+++ b/client/ydb_persqueue_core/ut/ut_utils/ut_utils.h
@@ -201,7 +201,7 @@ struct TYdbPqTestRetryState : NYdb::NPersQueue::IRetryPolicy::IRetryState {
     {}
 
     std::optional<TDuration> GetNextRetryDelay(NYdb::EStatus) override {
-        Cerr << "Test retry state: get retry delay\n";
+        std::cerr << "Test retry state: get retry delay\n";
         RetryDone();
         return Delay;
     }
@@ -226,17 +226,17 @@ struct TYdbPqTestRetryPolicy : IRetryPolicy {
     TYdbPqTestRetryPolicy(const TDuration& delay = TDuration::MilliSeconds(2000))
         : Delay(delay)
     {
-        Cerr << "====TYdbPqTestRetryPolicy()\n";
+        std::cerr << "====TYdbPqTestRetryPolicy()\n";
     }
 
     IRetryState::TPtr CreateRetryState() const override {
-        Cerr << "====CreateRetryState\n";
+        std::cerr << "====CreateRetryState\n";
         if (AtomicSwap(&OnFatalBreakDown, 0)) {
             return std::make_unique<TYdbPqNoRetryState>();
         }
         if (AtomicGet(Initialized_))
         {
-            Cerr << "====CreateRetryState Initialized\n";
+            std::cerr << "====CreateRetryState Initialized\n";
             auto res = AtomicSwap(&OnBreakDown, 0);
             UNIT_ASSERT(res);
             for (size_t i = 0; i < 100; i++) {
@@ -269,7 +269,7 @@ struct TYdbPqTestRetryPolicy : IRetryPolicy {
     }
     void ExpectBreakDown() {
         // Either TYdbPqTestRetryPolicy() or Initialize() should be called beforehand in order to set OnBreakDown=0
-        Cerr << "====ExpectBreakDown\n";
+        std::cerr << "====ExpectBreakDown\n";
         for (size_t i = 0; i < 100; i++) {
             if (AtomicGet(OnBreakDown) == 0)
                 break;
@@ -335,13 +335,13 @@ class TYdbPqTestExecutor : public IAsyncExecutor {
                 TFunction f;
                 while (TasksQueue.Dequeue(&f)) {
                     ++CurrentTaskId;
-                    Cerr << "Enqueue task with id " << CurrentTaskId << Endl;
+                    std::cerr << "Enqueue task with id " << CurrentTaskId << Endl;
                     Tasks[CurrentTaskId] = f;
                 }
                 ui64 id = 0;
                 while (ExecIdsQueue->Dequeue(&id)) {
                     ExecIds.push(id);
-                    Cerr << "Got ok to execute task with id " << id << Endl;
+                    std::cerr << "Got ok to execute task with id " << id << Endl;
 
                 }
                 while (!ExecIds.empty()) {
@@ -349,15 +349,15 @@ class TYdbPqTestExecutor : public IAsyncExecutor {
                     auto iter = Tasks.find(id);
                     if (iter == Tasks.end())
                         break;
-                    Cerr << "Executing compression of " << id << Endl;
+                    std::cerr << "Executing compression of " << id << Endl;
                     ExecIds.pop();
                     try {
                         (iter->second)();
                     } catch (...) {
-                        Cerr << "Failed on compression call: " << CurrentExceptionMessage() << Endl;
+                        std::cerr << "Failed on compression call: " << CurrentExceptionMessage() << Endl;
                         Y_ABORT();
                     }
-                    Cerr << "Compression of " << id << " Done\n";
+                    std::cerr << "Compression of " << id << " Done\n";
                     Tasks.erase(iter);
                 }
 
diff --git a/client/ydb_topic/ut/basic_usage_ut.cpp b/client/ydb_topic/ut/basic_usage_ut.cpp
index e200ab4347c..3bba9610343 100644
--- a/client/ydb_topic/ut/basic_usage_ut.cpp
+++ b/client/ydb_topic/ut/basic_usage_ut.cpp
@@ -78,7 +78,7 @@ void WriteAndReadToEndWithRestarts(TReadSessionSettings readSettings, TWriteSess
         [&]
         (TReadSessionEvent::TDataReceivedEvent& ev) mutable {
         AtomicSet(lastOffset, ev.GetMessages().back().GetOffset());
-        Cerr << ">>> TEST: last offset = " << lastOffset << Endl;
+        std::cerr << ">>> TEST: last offset = " << lastOffset << std::endl;
     });
 
     ReadSession = topicClient.CreateReadSession(readSettings);
@@ -143,24 +143,24 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
                         .Path(TEST_TOPIC)
                         .ProducerId(TEST_MESSAGE_GROUP_ID)
                         .MessageGroupId(TEST_MESSAGE_GROUP_ID);
-            Cerr << ">>> open write session " << i << Endl;
+            std::cerr << ">>> open write session " << i << std::endl;
             auto writeSession = client.CreateSimpleBlockingWriteSession(writeSettings);
             UNIT_ASSERT(writeSession->Write("message_using_MessageGroupId"));
-            Cerr << ">>> write session " << i << " message written" << Endl;
+            std::cerr << ">>> write session " << i << " message written" << std::endl;
             writeSession->Close();
-            Cerr << ">>> write session " << i << " closed" << Endl;
+            std::cerr << ">>> write session " << i << " closed" << std::endl;
         }
         {
             auto writeSettings = TWriteSessionSettings()
                         .Path(TEST_TOPIC)
                         .ProducerId(TEST_MESSAGE_GROUP_ID)
                         .PartitionId(0);
-            Cerr << ">>> open write session 100" << Endl;
+            std::cerr << ">>> open write session 100" << std::endl;
             auto writeSession = client.CreateSimpleBlockingWriteSession(writeSettings);
             UNIT_ASSERT(writeSession->Write("message_using_PartitionId"));
-            Cerr << ">>> write session 100 message written" << Endl;
+            std::cerr << ">>> write session 100 message written" << std::endl;
             writeSession->Close();
-            Cerr << ">>> write session 100 closed" << Endl;
+            std::cerr << ">>> write session 100 closed" << std::endl;
         }
 
         {
@@ -278,7 +278,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             if (shouldCaptureData.Defined()) {
                 TYdbStringBuilder msg;
                 msg << "Session has captured " << sessionAdapter.GetAcquiredMessagesCount()
-                    << " messages, capturing was expected: " << *shouldCaptureData << Endl;
+                    << " messages, capturing was expected: " << *shouldCaptureData << std::endl;
                 UNIT_ASSERT_VALUES_EQUAL_C(sessionAdapter.GetAcquiredMessagesCount() > 0, *shouldCaptureData, msg.c_str());
             }
         }
@@ -296,7 +296,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             .MaxMemoryUsageBytes(1_MB)
             .AppendTopics(setup->GetTestTopic());
 
-        Cerr << "Session was created" << Endl;
+        std::cerr << "Session was created" << std::endl;
 
         NThreading::TPromise<void> checkedPromise = NThreading::NewPromise<void>();
         auto totalReceived = 0u;
@@ -405,7 +405,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
                 writeSession->Close(TDuration::Seconds(10));
             }
             promiseToWrite.SetValue();
-            Cerr << ">>>TEST: write promise set " << Endl;
+            std::cerr << ">>>TEST: write promise set " << std::endl;
 
             {
                 NThreading::TPromise<void> promise = NThreading::NewPromise<void>();
@@ -415,7 +415,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
                     [promise = std::move(promise)](TReadSessionEvent::TDataReceivedEvent& ev) mutable {
                     ev.Commit();
                     promise.SetValue();
-                    Cerr << ">>>TEST: get read event " << Endl;
+                    std::cerr << ">>>TEST: get read event " << std::endl;
                 });
 
                 auto readSession = topicClient.CreateReadSession(readSettings);
@@ -423,7 +423,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
                 readSession->Close(TDuration::Seconds(10));
             }
             promiseToRead.SetValue();
-            Cerr << ">>>TEST: read promise set " << Endl;
+            std::cerr << ">>>TEST: read promise set " << std::endl;
         });
 
 
@@ -444,31 +444,31 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
 
         auto RunTasks = [&](auto e, const std::vector<size_t>& tasks) {
             size_t n = tasks.size();
-            Cerr << ">>>TEST in RunTasks: before WaitPlannedTasks" << Endl;
+            std::cerr << ">>>TEST in RunTasks: before WaitPlannedTasks" << std::endl;
             WaitPlannedTasks(e, n);
-            Cerr << ">>>TEST in RunTasks: before WaitExecutedTasks" << Endl;
+            std::cerr << ">>>TEST in RunTasks: before WaitExecutedTasks" << std::endl;
             size_t completed = e->GetExecutedCount();
             e->StartFuncs(tasks);
             WaitExecutedTasks(e, completed + n);
         };
 
         UNIT_ASSERT(!futureWrite.HasValue());
-        Cerr << ">>>TEST: future write has no value " << Endl;
+        std::cerr << ">>>TEST: future write has no value " << std::endl;
         RunTasks(stepByStepExecutor, {0});
         futureWrite.GetValueSync();
         UNIT_ASSERT(futureWrite.HasValue());
-        Cerr << ">>>TEST: future write has value " << Endl;
+        std::cerr << ">>>TEST: future write has value " << std::endl;
 
         UNIT_ASSERT(!futureRead.HasValue());
-        Cerr << ">>>TEST: future read has no value " << Endl;
+        std::cerr << ">>>TEST: future read has no value " << std::endl;
         RunTasks(stepByStepExecutor, {1});
         futureRead.GetValueSync();
         UNIT_ASSERT(futureRead.HasValue());
-        Cerr << ">>>TEST: future read has value " << Endl;
+        std::cerr << ">>>TEST: future read has value " << std::endl;
 
         f.get();
 
-        Cerr << ">>> TEST: gracefully closed" << Endl;
+        std::cerr << ">>> TEST: gracefully closed" << std::endl;
     }
 
     Y_UNIT_TEST(SessionNotDestroyedWhileUserEventHandlingInFlight) {
@@ -516,7 +516,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             // {
             //     std::shared_ptr<TContinuationToken> token;
             //     writeSettings.EventHandlers_.CommonHandler([token](TWriteSessionEvent::TEvent& event){
-            //         Cerr << ">>>TEST: in CommonHandler " << Endl;
+            //         std::cerr << ">>>TEST: in CommonHandler " << std::endl;
 
             //         if (std::holds_alternative<TWriteSessionEvent::TReadyToAcceptEvent>(event)) {
             //             *token = std::move(std::get<TWriteSessionEvent::TReadyToAcceptEvent>(event).ContinuationToken);
@@ -531,7 +531,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
             //     writeSession->Close(TDuration::Seconds(10));
             // }
             // promiseToWrite.SetValue();
-            // Cerr << ">>>TEST: write promise set " << Endl;
+            // std::cerr << ">>>TEST: write promise set " << std::endl;
 
             {
                 NThreading::TPromise<void> promise = NThreading::NewPromise<void>();
@@ -539,7 +539,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
 
                 readSettings.EventHandlers_.SimpleDataHandlers(
                     [promise = std::move(promise)](TReadSessionEvent::TDataReceivedEvent& ev) mutable {
-                    Cerr << ">>>TEST: in SimpleDataHandlers " << Endl;
+                    std::cerr << ">>>TEST: in SimpleDataHandlers " << std::endl;
                     ev.Commit();
                     promise.SetValue();
                 });
@@ -549,7 +549,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
                 readSession->Close(TDuration::Seconds(10));
             }
             promiseToRead.SetValue();
-            Cerr << ">>>TEST: read promise set " << Endl;
+            std::cerr << ">>>TEST: read promise set " << std::endl;
         });
 
 
@@ -570,9 +570,9 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
 
         auto RunTasks = [&](auto e, const std::vector<size_t>& tasks) {
             size_t n = tasks.size();
-            Cerr << ">>>TEST in RunTasks: before WaitPlannedTasks" << Endl;
+            std::cerr << ">>>TEST in RunTasks: before WaitPlannedTasks" << std::endl;
             WaitPlannedTasks(e, n);
-            Cerr << ">>>TEST in RunTasks: before WaitExecutedTasks" << Endl;
+            std::cerr << ">>>TEST in RunTasks: before WaitExecutedTasks" << std::endl;
             size_t completed = e->GetExecutedCount();
             e->StartFuncs(tasks);
             WaitExecutedTasks(e, completed + n);
@@ -580,25 +580,25 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
 
         // RunTasks(stepByStepExecutor, {0});
         // UNIT_ASSERT(!futureWrite.HasValue());
-        // Cerr << ">>>TEST: future write has no value " << Endl;
+        // std::cerr << ">>>TEST: future write has no value " << std::endl;
         // RunTasks(stepByStepExecutor, {1});
         // futureWrite.GetValueSync();
         // UNIT_ASSERT(futureWrite.HasValue());
-        // Cerr << ">>>TEST: future write has value " << Endl;
+        // std::cerr << ">>>TEST: future write has value " << std::endl;
 
         UNIT_ASSERT(!futureRead.HasValue());
-        Cerr << ">>>TEST: future read has no value " << Endl;
+        std::cerr << ">>>TEST: future read has no value " << std::endl;
         // 0: TStartPartitionSessionEvent
         RunTasks(stepByStepExecutor, {0});
         // 1: TDataReceivedEvent
         RunTasks(stepByStepExecutor, {1});
         futureRead.GetValueSync();
         UNIT_ASSERT(futureRead.HasValue());
-        Cerr << ">>>TEST: future read has value " << Endl;
+        std::cerr << ">>>TEST: future read has value " << std::endl;
 
         f.get();
 
-        Cerr << ">>> TEST: gracefully closed" << Endl;
+        std::cerr << ">>> TEST: gracefully closed" << std::endl;
     }
 
     Y_UNIT_TEST(ReadSessionCorrectClose) {
@@ -640,11 +640,11 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
         readSettings.EventHandlers_.SimpleDataHandlers(
             []
             (NYdb::NTopic::TReadSessionEvent::TDataReceivedEvent& ev) mutable {
-                Cerr << ">>> Got TDataReceivedEvent" << Endl;
+                std::cerr << ">>> Got TDataReceivedEvent" << std::endl;
                 ev.Commit();
         });
 
-        Cerr << ">>> TEST: Create session" << Endl;
+        std::cerr << ">>> TEST: Create session" << std::endl;
 
         ReadSession = topicClient.CreateReadSession(readSettings);
 
@@ -652,7 +652,7 @@ Y_UNIT_TEST_SUITE(BasicUsage) {
 
         ReadSession->Close();
         ReadSession = nullptr;
-        Cerr << ">>> TEST: Session gracefully closed" << Endl;
+        std::cerr << ">>> TEST: Session gracefully closed" << std::endl;
 
         Sleep(TDuration::Seconds(5));
 
diff --git a/client/ydb_topic/ut/local_partition_ut.cpp b/client/ydb_topic/ut/local_partition_ut.cpp
index 94e1ad28630..7431b1281ab 100644
--- a/client/ydb_topic/ut/local_partition_ut.cpp
+++ b/client/ydb_topic/ut/local_partition_ut.cpp
@@ -51,7 +51,7 @@ namespace NYdb::NTopic::NTests {
 
         void WriteMessage(TTopicClient& client)
         {
-            Cerr << "=== Write message" << Endl;
+            std::cerr << "=== Write message" << std::endl;
 
             auto writeSession = client.CreateSimpleBlockingWriteSession(CreateWriteSessionSettings());
             UNIT_ASSERT(writeSession->Write("message"));
@@ -60,7 +60,7 @@ namespace NYdb::NTopic::NTests {
 
         void ReadMessage(TTopicClient& client, ui64 expectedCommitedOffset = 1)
         {
-            Cerr << "=== Read message" << Endl;
+            std::cerr << "=== Read message" << std::endl;
 
             auto readSession = client.CreateReadSession(CreateReadSessionSettings());
 
@@ -103,13 +103,13 @@ namespace NYdb::NTopic::NTests {
             {
                 ui16 discoveryPort = TPortManager().GetPort();
                 DiscoveryAddr = TYdbStringBuilder() << "0.0.0.0:" << discoveryPort;
-                Cerr << "==== TMockDiscovery server started on port " << discoveryPort << Endl;
+                std::cerr << "==== TMockDiscovery server started on port " << discoveryPort << std::endl;
                 Server = ::NYdb::NTopic::NTests::NTestSuiteLocalPartition::StartGrpcServer(DiscoveryAddr, *this);
             }
 
             void SetGoodEndpoints(TTopicSdkTestSetup& setup)
             {
-                Cerr << "=== TMockDiscovery set good endpoint nodes " << Endl;
+                std::cerr << "=== TMockDiscovery set good endpoint nodes " << std::endl;
                 SetEndpoints(setup.GetRuntime().GetNodeId(0), setup.GetRuntime().GetNodeCount(), setup.GetServer().GrpcPort);
             }
 
@@ -117,7 +117,7 @@ namespace NYdb::NTopic::NTests {
             {
                 std::lock_guard lock(Lock);
 
-                Cerr << "==== TMockDiscovery add endpoints, firstNodeId " << firstNodeId << ", nodeCount " << nodeCount << ", port " << port << Endl;
+                std::cerr << "==== TMockDiscovery add endpoints, firstNodeId " << firstNodeId << ", nodeCount " << nodeCount << ", port " << port << std::endl;
 
                 MockResults.clear_endpoints();
                 if (nodeCount > 0)
@@ -146,7 +146,7 @@ namespace NYdb::NTopic::NTests {
 
                 if (Delay)
                 {
-                    Cerr << "==== Delay " << Delay << " before ListEndpoints request" << Endl;
+                    std::cerr << "==== Delay " << Delay << " before ListEndpoints request" << std::endl;
                     TInstant start = TInstant::Now();
                     while (start + Delay < TInstant::Now())
                     {
@@ -156,14 +156,14 @@ namespace NYdb::NTopic::NTests {
                     }
                 }
 
-                Cerr << "==== ListEndpoints request: " << request->ShortDebugString() << Endl;
+                std::cerr << "==== ListEndpoints request: " << request->ShortDebugString() << std::endl;
 
                 auto* op = response->mutable_operation();
                 op->set_ready(true);
                 op->set_status(Ydb::StatusIds::SUCCESS);
                 op->mutable_result()->PackFrom(MockResults);
 
-                Cerr << "==== ListEndpoints response: " << response->ShortDebugString() << Endl;
+                std::cerr << "==== ListEndpoints response: " << response->ShortDebugString() << std::endl;
                 return grpc::Status::OK;
             }
 
@@ -218,7 +218,7 @@ namespace NYdb::NTopic::NTests {
             auto [setup, client, discovery] = Start(TEST_CASE_NAME);
 
             for (size_t i = 1; i <= 10; ++i) {
-                Cerr << "=== Restart attempt " << i << Endl;
+                std::cerr << "=== Restart attempt " << i << std::endl;
                 setup->GetServer().KillTopicPqTablets(setup->GetTopicPath());
                 WriteMessage(*client);
                 ReadMessage(*client, i);
@@ -242,23 +242,23 @@ namespace NYdb::NTopic::NTests {
             retryPolicy->Initialize();
             retryPolicy->ExpectBreakDown();
 
-            Cerr << "=== Create write session\n";
+            std::cerr << "=== Create write session\n";
             TTopicClient client(TDriver(CreateConfig(*setup, discovery.GetDiscoveryAddr())));
             auto writeSession = client.CreateWriteSession(writeSettings);
 
-            Cerr << "=== Wait for retries\n";
+            std::cerr << "=== Wait for retries\n";
             retryPolicy->WaitForRetriesSync(3);
 
-            Cerr << "=== Alter partition count\n";
+            std::cerr << "=== Alter partition count\n";
             TAlterTopicSettings alterSettings;
             alterSettings.AlterPartitioningSettings(2, 2);
             auto alterResult = client.AlterTopic(setup->GetTopicPath(), alterSettings).GetValueSync();
             UNIT_ASSERT_VALUES_EQUAL_C(alterResult.GetStatus(), NYdb::EStatus::SUCCESS, alterResult.GetIssues().ToString());
 
-            Cerr << "=== Wait for repair\n";
+            std::cerr << "=== Wait for repair\n";
             retryPolicy->WaitForRepairSync();
 
-            Cerr << "=== Close write session\n";
+            std::cerr << "=== Close write session\n";
             writeSession->Close();
         }
 
@@ -276,19 +276,19 @@ namespace NYdb::NTopic::NTests {
             retryPolicy->Initialize();
             retryPolicy->ExpectBreakDown();
 
-            Cerr << "=== Create write session\n";
+            std::cerr << "=== Create write session\n";
             TTopicClient client(TDriver(CreateConfig(*setup, discovery.GetDiscoveryAddr())));
             auto writeSession = client.CreateWriteSession(writeSettings);
 
-            Cerr << "=== Wait for retries\n";
+            std::cerr << "=== Wait for retries\n";
             retryPolicy->WaitForRetriesSync(3);
 
             discovery.SetGoodEndpoints(*setup);
 
-            Cerr << "=== Wait for repair\n";
+            std::cerr << "=== Wait for repair\n";
             retryPolicy->WaitForRepairSync();
 
-            Cerr << "=== Close write session\n";
+            std::cerr << "=== Close write session\n";
             writeSession->Close();
         }
 
@@ -306,19 +306,19 @@ namespace NYdb::NTopic::NTests {
             retryPolicy->Initialize();
             retryPolicy->ExpectBreakDown();
 
-            Cerr << "=== Create write session\n";
+            std::cerr << "=== Create write session\n";
             TTopicClient client(TDriver(CreateConfig(*setup, discovery.GetDiscoveryAddr())));
             auto writeSession = client.CreateWriteSession(writeSettings);
 
-            Cerr << "=== Wait for retries\n";
+            std::cerr << "=== Wait for retries\n";
             retryPolicy->WaitForRetriesSync(3);
 
             discovery.SetGoodEndpoints(*setup);
 
-            Cerr << "=== Wait for repair\n";
+            std::cerr << "=== Wait for repair\n";
             retryPolicy->WaitForRepairSync();
 
-            Cerr << "=== Close write session\n";
+            std::cerr << "=== Close write session\n";
             writeSession->Close();
         }
 
@@ -336,11 +336,11 @@ namespace NYdb::NTopic::NTests {
             retryPolicy->Initialize();
             retryPolicy->ExpectBreakDown();
 
-            Cerr << "=== Create write session\n";
+            std::cerr << "=== Create write session\n";
             TTopicClient client(TDriver(CreateConfig(*setup, discovery.GetDiscoveryAddr())));
             auto writeSession = client.CreateWriteSession(writeSettings);
 
-            Cerr << "=== Close write session\n";
+            std::cerr << "=== Close write session\n";
             writeSession->Close();
         }
 
@@ -351,11 +351,11 @@ namespace NYdb::NTopic::NTests {
             discovery.SetGoodEndpoints(*setup);
             discovery.SetDelay(TDuration::Days(1));
 
-            Cerr << "=== Create write session\n";
+            std::cerr << "=== Create write session\n";
             TTopicClient client(TDriver(CreateConfig(*setup, discovery.GetDiscoveryAddr())));
             auto writeSession = client.CreateWriteSession(CreateWriteSessionSettings());
 
-            Cerr << "=== Close write session\n";
+            std::cerr << "=== Close write session\n";
             writeSession->Close();
         }
     }
diff --git a/client/ydb_topic/ut/ut_utils/topic_sdk_test_setup.cpp b/client/ydb_topic/ut/ut_utils/topic_sdk_test_setup.cpp
index 77130c8f310..74a0977e89e 100644
--- a/client/ydb_topic/ut/ut_utils/topic_sdk_test_setup.cpp
+++ b/client/ydb_topic/ut/ut_utils/topic_sdk_test_setup.cpp
@@ -9,7 +9,7 @@ TTopicSdkTestSetup::TTopicSdkTestSetup(const std::string& testCaseName, const NK
     , Server(settings, false)
 {
     Log.SetFormatter([testCaseName](ELogPriority priority, std::string_view message) {
-        return TYdbStringBuilder() << TInstant::Now() << " :" << testCaseName << " " << priority << ": " << message << Endl;
+        return TStringBuilder() << TInstant::Now() << " :" << testCaseName << " " << priority << ": " << message << Endl;
     });
 
     Server.StartServer(true, GetDatabase());
diff --git a/examples/basic_example/basic_example.cpp b/examples/basic_example/basic_example.cpp
index 44a37d05954..1464b3709c6 100644
--- a/examples/basic_example/basic_example.cpp
+++ b/examples/basic_example/basic_example.cpp
@@ -22,8 +22,8 @@ static void ThrowOnError(const TStatus& status) {
 }
 
 static void PrintStatus(const TStatus& status) {
-    Cerr << "Status: " << status.GetStatus() << Endl;
-    status.GetIssues().PrintTo(Cerr);
+    std::cerr << "Status: " << ToString(status.GetStatus()) << std::endl;
+    std::cerr << status.GetIssues().ToString();
 }
 
 static std::string JoinPath(const std::string& basePath, const std::string& path) {
@@ -95,9 +95,9 @@ static void DescribeTable(TTableClient client, const std::string& path, const st
         return result;
     }));
 
-    Cout << "> Describe table: " << name << Endl;
+    std::cout << "> Describe table: " << name << std::endl;
     for (auto& column : desc->GetColumns()) {
-        Cout << "Column, name: " << column.Name << ", type: " << FormatType(column.Type) << Endl;
+        std::cout << "Column, name: " << column.Name << ", type: " << FormatType(column.Type) << std::endl;
     }
 }
 
@@ -272,7 +272,7 @@ static TStatus PreparedSelectTransaction(TSession session, const std::string& pa
     }
 
     if (!prepareResult.IsQueryFromCache()) {
-        Cerr << "+Finished preparing query: PreparedSelectTransaction" << Endl;
+        std::cerr << "+Finished preparing query: PreparedSelectTransaction" << std::endl;
     }
 
     auto dataQuery = prepareResult.GetQuery();
@@ -441,11 +441,11 @@ void SelectSimple(TTableClient client, const std::string& path) {
 
     TResultSetParser parser(*resultSet);
     if (parser.TryNextRow()) {
-        Cout << "> SelectSimple:" << Endl << "Series"
-            << ", Id: " << parser.ColumnParser("series_id").GetOptionalUint64()
-            << ", Title: " << parser.ColumnParser("title").GetOptionalUtf8()
-            << ", Release date: " << parser.ColumnParser("release_date").GetOptionalString()
-            << Endl;
+        std::cout << "> SelectSimple:" << std::endl << "Series"
+            << ", Id: " << ToString(parser.ColumnParser("series_id").GetOptionalUint64())
+            << ", Title: " << ToString(parser.ColumnParser("title").GetOptionalUtf8())
+            << ", Release date: " << ToString(parser.ColumnParser("release_date").GetOptionalString())
+            << std::endl;
     }
 }
 
@@ -463,10 +463,10 @@ void SelectWithParams(TTableClient client, const std::string& path) {
 
     TResultSetParser parser(*resultSet);
     if (parser.TryNextRow()) {
-        Cout << "> SelectWithParams:" << Endl << "Season"
-            << ", Title: " << parser.ColumnParser("season_title").GetOptionalUtf8()
-            << ", Series title: " << parser.ColumnParser("series_title").GetOptionalUtf8()
-            << Endl;
+        std::cout << "> SelectWithParams:" << std::endl << "Season"
+            << ", Title: " << ToString(parser.ColumnParser("season_title").GetOptionalUtf8())
+            << ", Series title: " << ToString(parser.ColumnParser("series_title").GetOptionalUtf8())
+            << std::endl;
     }
 }
 
@@ -480,10 +480,10 @@ void PreparedSelect(TTableClient client, const std::string& path, ui32 seriesId,
     if (parser.TryNextRow()) {
         auto airDate = TInstant::Days(*parser.ColumnParser("air_date").GetOptionalUint64());
 
-        Cout << "> PreparedSelect:" << Endl << "Episode " << parser.ColumnParser("episode_id").GetOptionalUint64()
-            << ", Title: " << parser.ColumnParser("title").GetOptionalUtf8()
+        std::cout << "> PreparedSelect:" << std::endl << "Episode " << ToString(parser.ColumnParser("episode_id").GetOptionalUint64())
+            << ", Title: " << ToString(parser.ColumnParser("title").GetOptionalUtf8())
             << ", Air date: " << airDate.FormatLocalTime("%a %b %d, %Y")
-            << Endl;
+            << std::endl;
     }
 }
 
@@ -494,15 +494,15 @@ void MultiStep(TTableClient client, const std::string& path) {
     }));
 
     TResultSetParser parser(*resultSet);
-    Cout << "> MultiStep:" << Endl;
+    std::cout << "> MultiStep:" << std::endl;
     while (parser.TryNextRow()) {
         auto airDate = TInstant::Days(*parser.ColumnParser("air_date").GetOptionalUint64());
 
-        Cout << "Episode " << parser.ColumnParser("episode_id").GetOptionalUint64()
-            << ", Season: " << parser.ColumnParser("season_id").GetOptionalUint64()
-            << ", Title: " << parser.ColumnParser("title").GetOptionalUtf8()
+        std::cout << "Episode " << ToString(parser.ColumnParser("episode_id").GetOptionalUint64())
+            << ", Season: " << ToString(parser.ColumnParser("season_id").GetOptionalUint64())
+            << ", Title: " << ToString(parser.ColumnParser("title").GetOptionalUtf8())
             << ", Air date: " << airDate.FormatLocalTime("%a %b %d, %Y")
-            << Endl;
+            << std::endl;
     }
 }
 
@@ -536,19 +536,19 @@ void ScanQuerySelect(TTableClient client, const std::string& path) {
     auto result = client.StreamExecuteScanQuery(query, parameters).GetValueSync();
 
     if (!result.IsSuccess()) {
-        Cerr << "ScanQuery execution failure: " << result.GetIssues().ToString() << Endl;
+        std::cerr << "ScanQuery execution failure: " << result.GetIssues().ToString() << std::endl;
         return;
     }
 
     bool eos = false;
-    Cout << "> ScanQuerySelect:" << Endl;
+    std::cout << "> ScanQuerySelect:" << std::endl;
     while (!eos) {
         auto streamPart = result.ReadNext().ExtractValueSync();
 
         if (!streamPart.IsSuccess()) {
             eos = true;
             if (!streamPart.EOS()) {
-                Cerr << "ScanQuery execution failure: " << streamPart.GetIssues().ToString() << Endl;
+                std::cerr << "ScanQuery execution failure: " << streamPart.GetIssues().ToString() << std::endl;
             }
             continue;
         }
@@ -559,12 +559,12 @@ void ScanQuerySelect(TTableClient client, const std::string& path) {
 
             TResultSetParser parser(rs);
             while (parser.TryNextRow()) {
-                Cout << "Season"
-                     << ", SeriesId: " << parser.ColumnParser("series_id").GetOptionalUint64()
-                     << ", SeasonId: " << parser.ColumnParser("season_id").GetOptionalUint64()
-                     << ", Title: " << parser.ColumnParser("title").GetOptionalUtf8()
-                     << ", Air date: " << parser.ColumnParser("first_aired").GetOptionalString()
-                     << Endl;
+                std::cout << "Season"
+                     << ", SeriesId: " << ToString(parser.ColumnParser("series_id").GetOptionalUint64())
+                     << ", SeasonId: " << ToString(parser.ColumnParser("season_id").GetOptionalUint64())
+                     << ", Title: " << ToString(parser.ColumnParser("title").GetOptionalUtf8())
+                     << ", Air date: " << ToString(parser.ColumnParser("first_aired").GetOptionalString())
+                     << std::endl;
             }
         }
     }
@@ -601,7 +601,7 @@ bool Run(const TDriver& driver, const std::string& path) {
         ScanQuerySelect(client, path);
     }
     catch (const TYdbErrorException& e) {
-        Cerr << "Execution failed due to fatal error:" << Endl;
+        std::cerr << "Execution failed due to fatal error:" << std::endl;
         PrintStatus(e.Status);
         return false;
     }
diff --git a/examples/bulk_upsert_simple/main.cpp b/examples/bulk_upsert_simple/main.cpp
index b6b73ba81bd..167ef001b35 100644
--- a/examples/bulk_upsert_simple/main.cpp
+++ b/examples/bulk_upsert_simple/main.cpp
@@ -58,14 +58,14 @@ bool WriteLogBatch(NYdb::NTable::TTableClient& tableClient, const std::string& t
     auto status = tableClient.RetryOperationSync(bulkUpsertOperation, retrySettings);
 
     if (!status.IsSuccess()) {
-        Cerr << Endl << "Write failed with status: " << (const NYdb::TStatus&)status << Endl;
+        std::cerr << std::endl << "Write failed with status: " << ToString((const NYdb::TStatus&)status) << std::endl;
         return false;
     }
     return true;
 }
 
 bool CreateLogTable(NYdb::NTable::TTableClient& client, const std::string& table) {
-    Cerr << "Create table " << table << "\n";
+    std::cerr << "Create table " << table << "\n";
 
     NYdb::NTable::TRetryOperationSettings settings;
     auto status = client.RetryOperationSync([&table](NYdb::NTable::TSession session) {
@@ -82,7 +82,7 @@ bool CreateLogTable(NYdb::NTable::TTableClient& client, const std::string& table
         }, settings);
 
     if (!status.IsSuccess()) {
-        Cerr << "Create table failed with status: " << status << Endl;
+        std::cerr << "Create table failed with status: " << ToString(status) << std::endl;
         return false;
     }
     return true;
@@ -105,10 +105,10 @@ bool Run(const NYdb::TDriver &driver, const std::string &table, ui32 batchCount)
         if (!WriteLogBatch(client, table, logBatch, writeRetrySettings)) {
             return false;
         }
-        Cerr << ".";
+        std::cerr << ".";
     }
 
-    Cerr << Endl << "Done." << Endl;
+    std::cerr << std::endl << "Done." << std::endl;
     return true;
 }
 
diff --git a/examples/pagination/pagination.cpp b/examples/pagination/pagination.cpp
index 659bab796a1..9a13cd2cca5 100644
--- a/examples/pagination/pagination.cpp
+++ b/examples/pagination/pagination.cpp
@@ -22,8 +22,8 @@ static void ThrowOnError(const TStatus& status) {
 }
 
 static void PrintStatus(const TStatus& status) {
-    Cerr << "Status: " << status.GetStatus() << Endl;
-    status.GetIssues().PrintTo(Cerr);
+    std::cerr << "Status: " << ToString(status.GetStatus()) << std::endl;
+    std::cerr << status.GetIssues().ToString();
 }
 
 static std::string JoinPath(const std::string& basePath, const std::string& path) {
@@ -150,7 +150,7 @@ bool SelectPaging(TTableClient client, const std::string& path, ui64 pageLimit,
     do {
         lastCity = parser.ColumnParser("city").GetOptionalUtf8().value();
         lastNumber = parser.ColumnParser("number").GetOptionalUint32().value();
-        Cout << lastCity << ", Школа №" << lastNumber << ", Адрес: " << parser.ColumnParser("address").GetOptionalUtf8() << Endl;
+        std::cout << lastCity << ", Школа №" << lastNumber << ", Адрес: " << ToString(parser.ColumnParser("address").GetOptionalUtf8()) << std::endl;
     } while (parser.TryNextRow());
     return true;
 }
@@ -171,17 +171,17 @@ bool Run(const TDriver& driver, const std::string& path) {
         ui32 page = 0;
         bool pageNotEmpty = true;
 
-        Cout << "> Pagination, Limit=" << limit << Endl;
+        std::cout << "> Pagination, Limit=" << limit << std::endl;
 
         // show first MaxPages=10 pages:
         while (pageNotEmpty && page <= MaxPages) {
             ++page;
-            Cout << "> Page " << page << ":" << Endl;
+            std::cout << "> Page " << page << ":" << std::endl;
             pageNotEmpty = SelectPaging(client, path, limit, lastCity, lastNumber);
         }
     }
     catch (const TYdbErrorException& e) {
-        Cerr << "Execution failed due to fatal error:" << Endl;
+        std::cerr << "Execution failed due to fatal error:" << std::endl;
         PrintStatus(e.Status);
         return false;
     }
diff --git a/examples/secondary_index/main.cpp b/examples/secondary_index/main.cpp
index 2a70ada3bc2..70a540cd2e3 100644
--- a/examples/secondary_index/main.cpp
+++ b/examples/secondary_index/main.cpp
@@ -29,7 +29,7 @@ int main(int argc, char** argv) {
 
     ECmd cmd = ParseCmd(*argv);
     if (cmd == ECmd::NONE) {
-        Cerr << "Unsupported command '" << *argv << "'" << Endl;
+        std::cerr << "Unsupported command '" << *argv << "'" << std::endl;
         return 1;
     }
 
@@ -61,7 +61,7 @@ int main(int argc, char** argv) {
                 return RunDeleteSeries(driver, prefix, argc, argv);
         }
     } catch (const TYdbErrorException& e) {
-        Cerr << "Execution failed: " << e << Endl;
+        std::cerr << "Execution failed: " << ToString(e) << std::endl;
         return 1;
     }
 
diff --git a/examples/secondary_index/secondary_index_create.cpp b/examples/secondary_index/secondary_index_create.cpp
index 4d6432293f4..3b0151a003b 100644
--- a/examples/secondary_index/secondary_index_create.cpp
+++ b/examples/secondary_index/secondary_index_create.cpp
@@ -35,7 +35,7 @@ static void CreateSeriesIndexTable(TTableClient& client, const std::string& pref
 
 int RunCreateTables(TDriver& driver, const std::string& prefix, int argc, char**) {
     if (argc > 1) {
-        Cerr << "Unexpected arguments after create_tables" << Endl;
+        std::cerr << "Unexpected arguments after create_tables" << std::endl;
         return 1;
     }
 
diff --git a/examples/secondary_index/secondary_index_delete.cpp b/examples/secondary_index/secondary_index_delete.cpp
index dfefb49ebea..3a1d6d76414 100644
--- a/examples/secondary_index/secondary_index_delete.cpp
+++ b/examples/secondary_index/secondary_index_delete.cpp
@@ -74,6 +74,6 @@ int RunDeleteSeries(TDriver& driver, const std::string& prefix, int argc, char**
         return DeleteSeries(session, prefix, seriesId, deletedCount);
     }));
 
-    Cout << "Deleted " << deletedCount << " rows" << Endl;
+    std::cout << "Deleted " << deletedCount << " rows" << std::endl;
     return 0;
 }
diff --git a/examples/secondary_index/secondary_index_drop.cpp b/examples/secondary_index/secondary_index_drop.cpp
index 4ab3f70ff74..c6b7f84ca67 100644
--- a/examples/secondary_index/secondary_index_drop.cpp
+++ b/examples/secondary_index/secondary_index_drop.cpp
@@ -14,7 +14,7 @@ static void DropTable(TTableClient& client, const std::string& path) {
 
 int RunDropTables(TDriver& driver, const std::string& prefix, int argc, char**) {
     if (argc > 1) {
-        Cerr << "Unexpected arguments after drop_tables" << Endl;
+        std::cerr << "Unexpected arguments after drop_tables" << std::endl;
         return 1;
     }
 
diff --git a/examples/secondary_index/secondary_index_generate.cpp b/examples/secondary_index/secondary_index_generate.cpp
index 996bc19a672..d40696005d8 100644
--- a/examples/secondary_index/secondary_index_generate.cpp
+++ b/examples/secondary_index/secondary_index_generate.cpp
@@ -202,6 +202,6 @@ int RunGenerateSeries(TDriver& driver, const std::string& prefix, int argc, char
     }
 
     executor.Wait();
-    Cout << "Generated " << generated << " new series" << Endl;
+    std::cout << "Generated " << generated << " new series" << std::endl;
     return 0;
 }
diff --git a/examples/secondary_index/secondary_index_list.cpp b/examples/secondary_index/secondary_index_list.cpp
index b6c6f62ddc9..1f09a06c648 100644
--- a/examples/secondary_index/secondary_index_list.cpp
+++ b/examples/secondary_index/secondary_index_list.cpp
@@ -297,27 +297,27 @@ int RunListSeries(TDriver& driver, const std::string& prefix, int argc, char** a
         }
     }
     auto printLine = [&]() {
-        Cout << '+';
+        std::cout << '+';
         for (size_t i = 0; i < 5; ++i) {
             for (size_t k = 0; k < widths[i]; ++k) {
-                Cout << '-';
+                std::cout << '-';
             }
-            Cout << '+';
+            std::cout << '+';
         }
-        Cout << Endl;
+        std::cout << std::endl;
     };
     auto printRow = [&](size_t row) {
-        Cout << '|';
+        std::cout << '|';
         for (size_t i = 0; i < 5; ++i) {
-            Cout << ' ' << columns[i][row];
+            std::cout << ' ' << columns[i][row];
             size_t printed = 1 + GetNumberOfUTF8Chars(columns[i][row]);
             while (printed < widths[i]) {
-                Cout << ' ';
+                std::cout << ' ';
                 ++printed;
             }
-            Cout << '|';
+            std::cout << '|';
         }
-        Cout << Endl;
+        std::cout << std::endl;
     };
 
     printLine();
diff --git a/examples/secondary_index/secondary_index_update.cpp b/examples/secondary_index/secondary_index_update.cpp
index 7a449476a61..e15da5649a0 100644
--- a/examples/secondary_index/secondary_index_update.cpp
+++ b/examples/secondary_index/secondary_index_update.cpp
@@ -82,6 +82,6 @@ int RunUpdateViews(TDriver& driver, const std::string& prefix, int argc, char**
         return result;
     }));
 
-    Cout << "Updated " << updatedCount << " rows" << Endl;
+    std::cout << "Updated " << updatedCount << " rows" << std::endl;
     return 0;
 }
diff --git a/examples/secondary_index_builtin/main.cpp b/examples/secondary_index_builtin/main.cpp
index 2e26d31019d..3bf5640c3ca 100644
--- a/examples/secondary_index_builtin/main.cpp
+++ b/examples/secondary_index_builtin/main.cpp
@@ -28,7 +28,7 @@ int main(int argc, char** argv) {
     TCommand cmd = Parse(command.c_str());
 
     if (cmd == TCommand::NONE) {
-        Cerr << "Unsupported command: " << command << Endl;
+        std::cerr << "Unsupported command: " << command << std::endl;
         return 1;
     }
 
@@ -56,7 +56,7 @@ int main(int argc, char** argv) {
         }
 
     } catch (const TYdbErrorException& e) {
-        Cerr << "Execution failed: " << e << Endl;
+        std::cerr << "Execution failed: " << ToString(e) << std::endl;
         return 1;
     }
 }
diff --git a/examples/secondary_index_builtin/secondary_index_select.cpp b/examples/secondary_index_builtin/secondary_index_select.cpp
index 620dff5b2c4..ae4264ee311 100644
--- a/examples/secondary_index_builtin/secondary_index_select.cpp
+++ b/examples/secondary_index_builtin/secondary_index_select.cpp
@@ -55,8 +55,8 @@ int Select(TDriver& driver, const std::string& path, int argc, char **argv) {
     }));
 
     for (auto& item: selectResult) {
-        Cout << item.SeriesId << ' ' << item.Title << ' ' << item.Info << ' '
-            << item.ReleaseDate <<  ' ' << item.Views << ' ' << item.UploadedUserId <<  Endl;
+        std::cout << item.SeriesId << ' ' << item.Title << ' ' << item.Info << ' '
+            << item.ReleaseDate.ToString() <<  ' ' << item.Views << ' ' << item.UploadedUserId << std::endl;
     }
 
     return 0;
diff --git a/examples/secondary_index_builtin/secondary_index_select_join.cpp b/examples/secondary_index_builtin/secondary_index_select_join.cpp
index ba3872ceb81..f93a62c167e 100644
--- a/examples/secondary_index_builtin/secondary_index_select_join.cpp
+++ b/examples/secondary_index_builtin/secondary_index_select_join.cpp
@@ -60,7 +60,7 @@ int SelectJoin(TDriver& driver, const std::string& path, int argc, char **argv)
     }));
 
     for (auto& item : selectResult) {
-        Cout << item.SeriesId << ' ' << item.Title << Endl;
+        std::cout << item.SeriesId << ' ' << item.Title << std::endl;
     }
 
     return 0;
diff --git a/examples/topic_reader/eventloop/main.cpp b/examples/topic_reader/eventloop/main.cpp
index 2ef27b387ab..1cf0dae7834 100644
--- a/examples/topic_reader/eventloop/main.cpp
+++ b/examples/topic_reader/eventloop/main.cpp
@@ -35,7 +35,7 @@ struct TOptions {
 std::shared_ptr<NYdb::NTopic::IReadSession> ReadSession;
 
 void StopHandler(int) {
-    Cerr << "Stopping session" << Endl;
+    std::cerr << "Stopping session" << std::endl;
     if (ReadSession) {
         ReadSession->Close(TDuration::Seconds(3));
     } else {
@@ -74,7 +74,7 @@ int main(int argc, const char* argv[]) {
 
     ReadSession = topicClient.CreateReadSession(settings);
 
-    Cerr << "Session was created" << Endl;
+    std::cerr << "Session was created" << std::endl;
 
     // [BEGIN read session process events]
     // Event loop
@@ -83,15 +83,15 @@ int main(int argc, const char* argv[]) {
         // Wait for next event or ten seconds
         future.Wait(TDuration::Seconds(10));
         // future.Subscribe([](){
-        //    Cerr << ...;
+        //    std::cerr << ...;
         // });
         // Get event
         std::optional<NYdb::NTopic::TReadSessionEvent::TEvent> event = ReadSession->GetEvent(true/*block - will block if no event received yet*/);
-        Cerr << "Got new read session event: " << DebugString(*event) << Endl;
+        std::cerr << "Got new read session event: " << DebugString(*event) << std::endl;
 
         if (auto* dataEvent = std::get_if<NYdb::NTopic::TReadSessionEvent::TDataReceivedEvent>(&*event)) {
             for (const auto& message : dataEvent->GetMessages()) {
-                Cerr << "Data message: \"" << message.GetData() << "\"" << Endl;
+                std::cerr << "Data message: \"" << message.GetData() << "\"" << std::endl;
             }
 
             if (opts.CommitAfterProcessing) {
diff --git a/examples/topic_reader/simple/main.cpp b/examples/topic_reader/simple/main.cpp
index a72a4bb212f..5cf1fca585e 100644
--- a/examples/topic_reader/simple/main.cpp
+++ b/examples/topic_reader/simple/main.cpp
@@ -35,7 +35,7 @@ struct TOptions {
 std::shared_ptr<NYdb::NTopic::IReadSession> ReadSession;
 
 void StopHandler(int) {
-    Cerr << "Stopping session" << Endl;
+    std::cerr << "Stopping session" << std::endl;
     if (ReadSession) {
         ReadSession->Close(TDuration::Seconds(3));
     } else {
@@ -80,13 +80,13 @@ int main(int argc, const char* argv[]) {
     // settings.SetSimpleDataHandlers(
     settings.EventHandlers_.SimpleDataHandlers(
             [](NYdb::NTopic::TReadSessionEvent::TDataReceivedEvent& event) {
-            Cerr << "Data event " << DebugString(event);
+            std::cerr << "Data event " << DebugString(event);
         }, opts.CommitAfterProcessing);
 
     ReadSession = topicClient.CreateReadSession(settings);
     // [END Create read session]
 
-    Cerr << "Session was created" << Endl;
+    std::cerr << "Session was created" << std::endl;
 
     // Wait SessionClosed event.
     ReadSession->GetEvent(/*block = */true);
diff --git a/examples/topic_reader/transaction/application.cpp b/examples/topic_reader/transaction/application.cpp
index 171d2b7d37e..205ee36d6f4 100644
--- a/examples/topic_reader/transaction/application.cpp
+++ b/examples/topic_reader/transaction/application.cpp
@@ -37,7 +37,7 @@ void TApplication::CreateTopicReadSession(const TOptions& options)
 
     ReadSession = TopicClient->CreateReadSession(settings);
 
-    Cout << "Topic session was created" << Endl;
+    std::cout << "Topic session was created" << std::endl;
 }
 
 void TApplication::CreateTableSession()
@@ -48,7 +48,7 @@ void TApplication::CreateTableSession()
 
     TableSession = result.GetSession();
 
-    Cout << "Table session was created" << Endl;
+    std::cout << "Table session was created" << std::endl;
 }
 
 void TApplication::Run()
@@ -120,7 +120,7 @@ void TApplication::CommitTransaction()
 
     auto result = Transaction->Commit(settings).GetValueSync();
 
-    Cout << "Commit: " << static_cast<NYdb::TStatus&>(result) << Endl;
+    std::cout << "Commit: " << ToString(static_cast<NYdb::TStatus&>(result)) << std::endl;
 }
 
 void TApplication::TryCommitTransaction()
diff --git a/examples/topic_reader/transaction/main.cpp b/examples/topic_reader/transaction/main.cpp
index 95cc49edc22..f3af9a2a0b6 100644
--- a/examples/topic_reader/transaction/main.cpp
+++ b/examples/topic_reader/transaction/main.cpp
@@ -9,7 +9,7 @@ std::optional<TApplication> App;
 
 void StopHandler(int)
 {
-    Cout << "Stopping session" << Endl;
+    std::cout << "Stopping session" << std::endl;
     if (App) {
         App->Stop();
     } else {
@@ -25,10 +25,10 @@ int main(int argc, const char* argv[])
     TOptions options(argc, argv);
 
     App.emplace(options);
-    Cout << "Application initialized" << Endl;
+    std::cout << "Application initialized" << std::endl;
 
     App->Run();
-    Cout << "Event loop completed" << Endl;
+    std::cout << "Event loop completed" << std::endl;
 
     App->Finalize();
 }
diff --git a/examples/ttl/ttl.cpp b/examples/ttl/ttl.cpp
index aff575f49d8..a7c8861df41 100644
--- a/examples/ttl/ttl.cpp
+++ b/examples/ttl/ttl.cpp
@@ -211,18 +211,18 @@ static TStatus DeleteDocumentWithTimestamp(TSession session, const std::string&
 void AddDocument(TTableClient client, const std::string& path, const std::string& url,
     const std::string& html, const ui64 timestamp)
 {
-    Cout << "> AddDocument:" << Endl
-         << " Url: " << url << Endl
-         << " Timestamp: " << timestamp << Endl;
+    std::cout << "> AddDocument:" << std::endl
+         << " Url: " << url << std::endl
+         << " Timestamp: " << timestamp << std::endl;
 
     ThrowOnError(client.RetryOperationSync([path, url, html, timestamp](TSession session) {
         return AddDocumentTransaction(session, path, url, html, timestamp);
     }));
-    Cout << Endl;
+    std::cout << std::endl;
 }
 
 void ReadDocument(TTableClient client, const std::string& path, const std::string& url) {
-    Cout << "> ReadDocument \"" << url << "\":" << Endl;
+    std::cout << "> ReadDocument \"" << url << "\":" << std::endl;
     std::optional<TResultSet> resultSet;
     ThrowOnError(client.RetryOperationSync([path, url, &resultSet] (TSession session) {
         return ReadDocumentTransaction(session, path, url, resultSet);
@@ -230,18 +230,18 @@ void ReadDocument(TTableClient client, const std::string& path, const std::strin
 
     TResultSetParser parser(*resultSet);
     if (parser.TryNextRow()) {
-        Cout << " DocId: " << parser.ColumnParser("doc_id").GetOptionalUint64() << Endl
-            << " Url: " << parser.ColumnParser("url").GetOptionalUtf8() << Endl
-            << " Timestamp: " << parser.ColumnParser("timestamp").GetOptionalUint64() << Endl
-            << " Html: " << parser.ColumnParser("html").GetOptionalUtf8() << Endl;
+        std::cout << " DocId: " << ToString(parser.ColumnParser("doc_id").GetOptionalUint64()) << std::endl
+            << " Url: " << ToString(parser.ColumnParser("url").GetOptionalUtf8()) << std::endl
+            << " Timestamp: " << ToString(parser.ColumnParser("timestamp").GetOptionalUint64()) << std::endl
+            << " Html: " << ToString(parser.ColumnParser("html").GetOptionalUtf8()) << std::endl;
     } else {
-        Cout << " Not found" << Endl;
+        std::cout << " Not found" << std::endl;
     }
-    Cout << Endl;
+    std::cout << std::endl;
 }
 
 void DeleteExpired(TTableClient client, const std::string& path, const ui32 queue, const ui64 timestamp) {
-    Cout << "> DeleteExpired from queue #" << queue << ":" << Endl;
+    std::cout << "> DeleteExpired from queue #" << queue << ":" << std::endl;
     bool empty = false;
     ui64 lastTimestamp = 0;
     ui64 lastDocId = 0;
@@ -257,14 +257,14 @@ void DeleteExpired(TTableClient client, const std::string& path, const ui32 queu
             empty = false;
             lastDocId  = *parser.ColumnParser("doc_id").GetOptionalUint64();
             lastTimestamp = *parser.ColumnParser("timestamp").GetOptionalUint64();
-            Cout << " DocId: " << lastDocId << " Timestamp: " << lastTimestamp << Endl;
+            std::cout << " DocId: " << lastDocId << " Timestamp: " << lastTimestamp << std::endl;
 
             ThrowOnError(client.RetryOperationSync([path, queue, lastDocId, lastTimestamp] (TSession session) {
                 return DeleteDocumentWithTimestamp(session, path, queue, lastDocId, lastTimestamp);
             }));
         }
     }
-    Cout << Endl;
+    std::cout << std::endl;
 }
 ///////////////////////////////////////////////////////////////////////////////
 
@@ -311,7 +311,7 @@ bool Run(const TDriver& driver, const std::string& path) {
         ReadDocument(client, path, "https://ya.ru/");
     }
     catch (const TYdbErrorException& e) {
-        Cerr << "Execution failed due to fatal error:" << Endl;
+        std::cerr << "Execution failed due to fatal error:" << std::endl;
         PrintStatus(e.Status);
         return false;
     }
diff --git a/examples/ttl/util.h b/examples/ttl/util.h
index fe350067305..dc20477ae11 100644
--- a/examples/ttl/util.h
+++ b/examples/ttl/util.h
@@ -25,8 +25,8 @@ inline void ThrowOnError(const TStatus& status) {
 }
 
 inline void PrintStatus(const TStatus& status) {
-    Cerr << "Status: " << status.GetStatus() << Endl;
-    status.GetIssues().PrintTo(Cerr);
+    std::cerr << "Status: " << ToString(status.GetStatus()) << std::endl;
+    std::cerr << status.GetIssues().ToString();
 }
 
 inline std::string JoinPath(const std::string& basePath, const std::string& path) {
diff --git a/library/cpp/blockcodecs/codecs_ut.cpp b/library/cpp/blockcodecs/codecs_ut.cpp
index e99cd6d6ce8..4d02b518734 100644
--- a/library/cpp/blockcodecs/codecs_ut.cpp
+++ b/library/cpp/blockcodecs/codecs_ut.cpp
@@ -59,7 +59,7 @@ Y_UNIT_TEST_SUITE(TBlockCodecsTest) {
                     d.AsString(res);
                     UNIT_ASSERT_EQUAL(NBlockCodecs::TData(res), NBlockCodecs::TData(data));
                 } catch (...) {
-                    Cerr << c->Name() << "(" << res.Quote() << ")(" << std::string{NBlockCodecs::TData(data)}.Quote() << ")" << Endl;
+                    std::cerr << c->Name() << "(" << res.Quote() << ")(" << std::string{NBlockCodecs::TData(data)}.Quote() << ")" << std::endl;
 
                     throw;
                 }
@@ -183,7 +183,7 @@ Y_UNIT_TEST_SUITE(TBlockCodecsTest) {
             try {
                 UNIT_ASSERT_EQUAL(resNew, res);
             } catch (...) {
-                Cerr << c->Name() << Endl;
+                std::cerr << c->Name() << std::endl;
 
                 throw;
             }
diff --git a/library/cpp/coroutine/engine/coroutine_ut.cpp b/library/cpp/coroutine/engine/coroutine_ut.cpp
index 9ec91cafb0b..406212d255c 100644
--- a/library/cpp/coroutine/engine/coroutine_ut.cpp
+++ b/library/cpp/coroutine/engine/coroutine_ut.cpp
@@ -634,11 +634,11 @@ namespace NCoroTestFastPathWake {
             UNIT_ASSERT_VALUES_EQUAL(res.Checked(), 0);
             state.IoSleepRunning = false;
         } catch (const NUnitTest::TAssertException& ex) {
-            Cerr << ex.AsStrBuf() << Endl;
-            ex.BackTrace()->PrintTo(Cerr);
+            std::cerr << ex.AsStrBuf() << std::endl;
+            ex.BackTrace()->PrintTo(std::cerr);
             throw;
         } catch (...) {
-            Cerr << CurrentExceptionMessage() << Endl;
+            std::cerr << CurrentExceptionMessage() << std::endl;
             throw;
         }
     }
@@ -697,11 +697,11 @@ namespace NCoroTestFastPathWake {
             // Check everything has ended sooner than the timeout
             UNIT_ASSERT(TInstant::Now() - start < TDuration::Seconds(1));
         } catch (const NUnitTest::TAssertException& ex) {
-            Cerr << ex.AsStrBuf() << Endl;
-            ex.BackTrace()->PrintTo(Cerr);
+            std::cerr << ex.AsStrBuf() << std::endl;
+            ex.BackTrace()->PrintTo(std::cerr);
             throw;
         } catch (...) {
-            Cerr << CurrentExceptionMessage() << Endl;
+            std::cerr << CurrentExceptionMessage() << std::endl;
             throw;
         }
     }
diff --git a/library/cpp/coroutine/engine/impl.cpp b/library/cpp/coroutine/engine/impl.cpp
index 8acf7a90e16..fd4e09cfadc 100644
--- a/library/cpp/coroutine/engine/impl.cpp
+++ b/library/cpp/coroutine/engine/impl.cpp
@@ -9,6 +9,8 @@
 #include <util/stream/output.h>
 #include <util/system/yassert.h>
 
+#include <iostream>
+
 TCont::TJoinWait::TJoinWait(TCont& c) noexcept
     : Cont_(c)
 {}
@@ -355,7 +357,7 @@ void TContExecutor::RunScheduler() noexcept {
             }
         }
     } catch (...) {
-        TBackTrace::FromCurrentException().PrintTo(Cerr);
+        std::cerr << TBackTrace::FromCurrentException().PrintToString();
         Y_ABORT("Uncaught exception in the scheduler: %s", CurrentExceptionMessage().c_str());
     }
 }
diff --git a/library/cpp/cppparser/parser.cpp b/library/cpp/cppparser/parser.cpp
index b5d0c1205e7..72b8dc5d384 100644
--- a/library/cpp/cppparser/parser.cpp
+++ b/library/cpp/cppparser/parser.cpp
@@ -106,8 +106,8 @@ class TCppSaxParser::TImpl {
             }
 
 #if DEBUG_ME
-            Cerr << "char: " << ch << Endl;
-            Cerr << "state before: " << (unsigned int)State_ << Endl;
+            std::cerr << "char: " << ch << std::endl;
+            std::cerr << "state before: " << (unsigned int)State_ << std::endl;
 #endif
 
         retry:
@@ -348,7 +348,7 @@ class TCppSaxParser::TImpl {
             }
 
 #if DEBUG_ME
-            Cerr << "state after: " << (unsigned int)State_ << Endl;
+            std::cerr << "state after: " << (unsigned int)State_ << std::endl;
 #endif
 
             ++data;
diff --git a/library/cpp/dbg_output/auto.h b/library/cpp/dbg_output/auto.h
index 8d96167f6ac..d16574938d6 100644
--- a/library/cpp/dbg_output/auto.h
+++ b/library/cpp/dbg_output/auto.h
@@ -2,13 +2,13 @@
 
 #include <util/generic/va_args.h>
 
-// int a = 1, b = 2; Cout << LabeledDump(a, b, 1 + 2); yields {"a": 1, "b": 2, "1 + 2": 3}
+// int a = 1, b = 2; std::cout << LabeledDump(a, b, 1 + 2); yields {"a": 1, "b": 2, "1 + 2": 3}
 #define LabeledDump(...) \
     '{' Y_PASS_VA_ARGS(Y_MAP_ARGS_WITH_LAST(__LABELED_DUMP_NONLAST__, __LABELED_DUMP_IMPL__, __VA_ARGS__)) << '}'
 #define __LABELED_DUMP_IMPL__(x) << "\"" #x "\": " << DbgDump(x)
 #define __LABELED_DUMP_NONLAST__(x) __LABELED_DUMP_IMPL__(x) << ", "
 
-// Usage: struct TMyStruct { int A, B; }; DEFINE_DUMPER(TMyStruct, A, B); Cout << TMyStruct{3, 4};
+// Usage: struct TMyStruct { int A, B; }; DEFINE_DUMPER(TMyStruct, A, B); std::cout << TMyStruct{3, 4};
 // yields {"A": 3, "B": 4}
 #define DEFINE_DUMPER(C, ...)                                                                                                                       \
     template <>                                                                                                                                     \
diff --git a/library/cpp/dbg_output/dump.h b/library/cpp/dbg_output/dump.h
index c7efa105ee6..6f6f338fbf2 100644
--- a/library/cpp/dbg_output/dump.h
+++ b/library/cpp/dbg_output/dump.h
@@ -11,9 +11,9 @@
 #include <utility>
 
 /*
- * Cout << DbgDump(any) << Endl;
- * Cout << DbgDumpDeep(any) << Endl;
- * Cout << DbgDump(any).SetIndent(true) << Endl;
+ * std::cout << DbgDump(any) << std::endl;
+ * std::cout << DbgDumpDeep(any) << std::endl;
+ * std::cout << DbgDump(any).SetIndent(true) << std::endl;
  *
  * specialize TDumper<your type> for extending dumper
  */
diff --git a/library/cpp/diff/diff_ut.cpp b/library/cpp/diff/diff_ut.cpp
index 140db6a4642..7a3ac24c952 100644
--- a/library/cpp/diff/diff_ut.cpp
+++ b/library/cpp/diff/diff_ut.cpp
@@ -53,7 +53,7 @@ Y_UNIT_TEST_SUITE(DiffTokens) {
         TDiffTester tester;
 
         tester.Test("aaa", "aaa");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "aaa");
     }
 
@@ -61,11 +61,11 @@ Y_UNIT_TEST_SUITE(DiffTokens) {
         TDiffTester tester;
 
         tester.Test("aaa", "bbb");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(aaa|bbb)");
 
         tester.Test("aaa", "bbbb");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(aaa|bbbb)");
     }
 
@@ -73,19 +73,19 @@ Y_UNIT_TEST_SUITE(DiffTokens) {
         TDiffTester tester;
 
         tester.Test("aaa", "abb", "");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "a(aa|bb)");
 
         tester.Test("aac", "abc", "");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "a(a|b)c");
 
         tester.Test("123", "133", "");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "1(2|3)3");
 
         tester.Test("[1, 2, 3]", "[1, 3, 3]", "");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "[1, (2|3), 3]");
     }
 
@@ -93,7 +93,7 @@ Y_UNIT_TEST_SUITE(DiffTokens) {
         TDiffTester tester;
 
         tester.Test("abcde", "accfg");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(abcde|accfg)");
     }
 
@@ -103,7 +103,7 @@ Y_UNIT_TEST_SUITE(DiffTokens) {
         std::string_view str("aaa bbb");
         tester.Test(str, str);
 
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "aaa bbb");
     }
 
@@ -111,11 +111,11 @@ Y_UNIT_TEST_SUITE(DiffTokens) {
         TDiffTester tester;
 
         tester.Test("aaa bbb", "ccc ddd");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(aaa|ccc) (bbb|ddd)");
 
         tester.Test("aaa bbb", "c d");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(aaa|c) (bbb|d)");
     }
 
@@ -123,11 +123,11 @@ Y_UNIT_TEST_SUITE(DiffTokens) {
         TDiffTester tester;
 
         tester.Test("aaa ccd", "abb cce");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(aaa|abb) (ccd|cce)");
 
         tester.Test("aac cbb", "aa bb");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(aac|aa) (cbb|bb)");
     }
 
@@ -135,19 +135,19 @@ Y_UNIT_TEST_SUITE(DiffTokens) {
         TDiffTester tester;
 
         tester.Test("aaa bbb", "bbb aaa");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(|bbb )aaa( bbb|)");
 
         tester.Test("aaa bbb", " bbb aaa");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(aaa|) bbb(| aaa)");
 
         tester.Test(" aaa bbb ", " bbb aaa ");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(| bbb) aaa (bbb |)");
 
         tester.Test("aaa bb", " bbb aa");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(aaa|) (bb|bbb aa)");
     }
 
@@ -155,19 +155,19 @@ Y_UNIT_TEST_SUITE(DiffTokens) {
         TDiffTester tester;
 
         tester.Test("aaa bbb", "aaa");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "aaa( bbb|)");
 
         tester.Test("aaa bbb", "aaa ");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "aaa (bbb|)");
 
         tester.Test("aaa bbb", " bbb");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(aaa|) bbb");
 
         tester.Test("aaa bbb", "bbb");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "(aaa |)bbb");
     }
 
@@ -175,11 +175,11 @@ Y_UNIT_TEST_SUITE(DiffTokens) {
         TDiffTester tester;
 
         tester.Test("aaa\nabc\nbbb", "aaa\nacc\nbbb");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "aaa\n(abc|acc)\nbbb");
 
         tester.Test("aaa\nabc\nbbb", "aaa\nac\nbbb");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "aaa\n(abc|ac)\nbbb");
     }
 
@@ -187,11 +187,11 @@ Y_UNIT_TEST_SUITE(DiffTokens) {
         TDiffTester tester;
 
         tester.Test("aaa bbb", "aaa\tbbb");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "aaa( |\t)bbb");
 
         tester.Test(" aaa\tbbb\n", "\taaa\nbbb ");
-        //~ Cerr << tester.Result() << Endl;
+        //~ std::cerr << tester.Result() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(tester.Result(), "( |\t)aaa(\t|\n)bbb(\n| )");
     }
 }
diff --git a/library/cpp/getopt/last_getopt_demo/demo.cpp b/library/cpp/getopt/last_getopt_demo/demo.cpp
index 66f81e94547..967afb7bcb3 100644
--- a/library/cpp/getopt/last_getopt_demo/demo.cpp
+++ b/library/cpp/getopt/last_getopt_demo/demo.cpp
@@ -2,6 +2,8 @@
 #include <library/cpp/getopt/modchooser.h>
 #include <library/cpp/colorizer/colors.h>
 
+#include <iostream>
+
 // For the sake of this example, let's implement Wget
 
 Y_COMPLETER(HeaderCompleter) {
@@ -59,7 +61,7 @@ class TMain: public TMainClassArgs {
             .IfPresentDisableCompletion()
             .NoArgument()
             .Handler([]() {
-                Cerr << "last_getopt_demo 1.0.0" << Endl;
+                std::cerr << "last_getopt_demo 1.0.0" << std::endl;
                 exit(0);
             });
 
@@ -208,28 +210,28 @@ class TMain: public TMainClassArgs {
 
         std::string method = ExplicitMethod_ ? ExplicitMethod_ : ImplicitMethod_;
 
-        Cerr << ST_LIGHT << "Settings:" << RESET << Endl;
-        Cerr << GREEN << "  Background: " << RESET << Background_ << Endl;
-        Cerr << GREEN << "  Timeout: " << RESET << Timeout_ << Endl;
-        Cerr << GREEN << "  Method: " << RESET << method.Quote() << Endl;
-        Cerr << GREEN << "  UserAgent: " << RESET << UserAgent_.Quote() << Endl;
-        Cerr << GREEN << "  PostData: " << RESET << (PostData_ ? PostData_->Quote() : "Nothing") << Endl;
-        Cerr << GREEN << "  PostFile: " << RESET << (PostFile_ ? PostFile_->Quote() : "Nothing") << Endl;
+        std::cerr << ST_LIGHT << "Settings:" << RESET << std::endl;
+        std::cerr << GREEN << "  Background: " << RESET << Background_ << std::endl;
+        std::cerr << GREEN << "  Timeout: " << RESET << Timeout_ << std::endl;
+        std::cerr << GREEN << "  Method: " << RESET << method.Quote() << std::endl;
+        std::cerr << GREEN << "  UserAgent: " << RESET << UserAgent_.Quote() << std::endl;
+        std::cerr << GREEN << "  PostData: " << RESET << (PostData_ ? PostData_->Quote() : "Nothing") << std::endl;
+        std::cerr << GREEN << "  PostFile: " << RESET << (PostFile_ ? PostFile_->Quote() : "Nothing") << std::endl;
 
-        Cerr << ST_LIGHT << "Headers:" << RESET << Endl;
+        std::cerr << ST_LIGHT << "Headers:" << RESET << std::endl;
         for (auto& header : Headers_) {
-            Cerr << "  " << header.Quote() << Endl;
+            std::cerr << "  " << header.Quote() << std::endl;
         }
         if (!Headers_) {
-            Cerr << GREEN << "  no headers" << RESET << Endl;
+            std::cerr << GREEN << "  no headers" << RESET << std::endl;
         }
 
-        Cerr << ST_LIGHT << "Will download the following URLs:" << RESET << Endl;
+        std::cerr << ST_LIGHT << "Will download the following URLs:" << RESET << std::endl;
         for (auto& arg : parsedOptions.GetFreeArgs()) {
-            Cerr << "  " << arg.Quote() << Endl;
+            std::cerr << "  " << arg.Quote() << std::endl;
         }
         if (!parsedOptions.GetFreeArgs()) {
-            Cerr << "  no urls" << Endl;
+            std::cerr << "  no urls" << std::endl;
         }
         return 0;
     }
diff --git a/library/cpp/getopt/small/completer.cpp b/library/cpp/getopt/small/completer.cpp
index 045c4146af7..598253b3898 100644
--- a/library/cpp/getopt/small/completer.cpp
+++ b/library/cpp/getopt/small/completer.cpp
@@ -5,6 +5,8 @@
 #include <util/string/builder.h>
 #include <library/cpp/string_utils/misc/misc.h>
 
+#include <iostream>
+
 using NLastGetopt::NEscaping::Q;
 using NLastGetopt::NEscaping::QQ;
 using NLastGetopt::NEscaping::C;
@@ -263,7 +265,7 @@ namespace NLastGetopt::NComp {
     }
 
     void TCustomCompleter::AddCompletion(std::string_view completion) {
-        Cout << completion << Endl;  // this was easy =)
+        std::cout << completion << std::endl;  // this was easy =)
         // TODO: support option descriptions and messages
     }
 
@@ -275,12 +277,12 @@ namespace NLastGetopt::NComp {
         }
 
         if (!root.empty()) {
-            Cout << root << Sep_ << Endl;
+            std::cout << root << Sep_ << std::endl;
         } else {
-            Cout << Endl;
+            std::cout << std::endl;
         }
 
-        Cout << Sep_ << Endl;
+        std::cout << Sep_ << std::endl;
 
         GenerateCompletionParts(argc, argv, curIdx, cur, prefix, suffix, root);
     }
diff --git a/library/cpp/getopt/small/completer_command.cpp b/library/cpp/getopt/small/completer_command.cpp
index 8226c0f9de6..75734bbedb7 100644
--- a/library/cpp/getopt/small/completer_command.cpp
+++ b/library/cpp/getopt/small/completer_command.cpp
@@ -7,6 +7,8 @@
 #include <library/cpp/colorizer/colors.h>
 #include <library/cpp/string_utils/misc/misc.h>
 
+#include <iostream>
+
 namespace NLastGetopt {
     std::string MakeInfo(std::string_view command, std::string_view flag) {
         std::string info = (
@@ -97,13 +99,13 @@ namespace NLastGetopt {
             .Completer(ShellChoiceCompleter())
             .Handler1T<std::string>([opts, command, name](std::string_view shell) {
                 if (shell.empty()) {
-                    Cerr << Wrap(80, MakeInfo(command, "--" + name)) << Endl;
+                    std::cerr << Wrap(80, MakeInfo(command, "--" + name)) << std::endl;
                 } else if (shell == "bash") {
                     TBashCompletionGenerator(opts).Generate(command, Cout);
                 } else if (shell == "zsh") {
                     TZshCompletionGenerator(opts).Generate(command, Cout);
                 } else {
-                    Cerr << "Unknown shell name " << NUtils::Quote(shell) << Endl;
+                    std::cerr << "Unknown shell name " << NUtils::Quote(shell) << std::endl;
                     exit(1);
                 }
                 exit(0);
@@ -144,7 +146,7 @@ namespace NLastGetopt {
             } else if (arg == "zsh") {
                 TZshCompletionGenerator(Modes_).Generate(Command_, Cout);
             } else {
-                Cerr << "Unknown shell name " << NUtils::Quote(arg) << Endl;
+                std::cerr << "Unknown shell name " << NUtils::Quote(arg) << std::endl;
                 parsedOptions.PrintUsage();
                 return 1;
             }
diff --git a/library/cpp/getopt/small/last_getopt_opts.cpp b/library/cpp/getopt/small/last_getopt_opts.cpp
index 466e9289212..9bba442f513 100644
--- a/library/cpp/getopt/small/last_getopt_opts.cpp
+++ b/library/cpp/getopt/small/last_getopt_opts.cpp
@@ -9,7 +9,8 @@
 #include <util/generic/algorithm.h>
 #include <util/stream/format.h>
 
-#include <stdlib.h>
+#include <cstdlib>
+#include <iostream>
 
 namespace NLastGetoptPrivate {
     std::string& VersionString() {
@@ -26,12 +27,12 @@ namespace NLastGetopt {
     static const std::string_view SPad = "  ";
 
     void PrintVersionAndExit(const TOptsParser*) {
-        Cout << (!NLastGetoptPrivate::VersionString().empty() ? NLastGetoptPrivate::VersionString() : "program version: not linked with library/cpp/getopt") << Endl;
+        std::cout << (!NLastGetoptPrivate::VersionString().empty() ? NLastGetoptPrivate::VersionString() : "program version: not linked with library/cpp/getopt") << std::endl;
         exit(NLastGetoptPrivate::VersionString().empty());
     }
 
     void PrintShortVersionAndExit(const std::string& appName) {
-        Cout << appName << " version " << (!NLastGetoptPrivate::ShortVersionString().empty() ? NLastGetoptPrivate::ShortVersionString() : "not linked with library/cpp/getopt") << Endl;
+        std::cout << appName << " version " << (!NLastGetoptPrivate::ShortVersionString().empty() ? NLastGetoptPrivate::ShortVersionString() : "not linked with library/cpp/getopt") << std::endl;
         exit(NLastGetoptPrivate::ShortVersionString().empty());
     }
 
diff --git a/library/cpp/getopt/small/last_getopt_parse_result.cpp b/library/cpp/getopt/small/last_getopt_parse_result.cpp
index 42522264c33..0416f6ebcea 100644
--- a/library/cpp/getopt/small/last_getopt_parse_result.cpp
+++ b/library/cpp/getopt/small/last_getopt_parse_result.cpp
@@ -1,5 +1,7 @@
 #include "last_getopt_parse_result.h"
 
+#include <iostream>
+
 namespace NLastGetopt {
     const TOptParseResult* TOptsParseResult::FindParseResult(const TdVec& vec, const TOpt* opt) {
         for (const auto& r : vec) {
@@ -162,10 +164,10 @@ namespace NLastGetopt {
     }
 
     void TOptsParseResult::HandleError() const {
-        Cerr << CurrentExceptionMessage() << Endl;
+        std::cerr << CurrentExceptionMessage() << std::endl;
         if (Parser_.Get()) { // parser initializing can fail (and we get here, see Init)
             if (Parser_->Opts_->FindLongOption("help") != nullptr) {
-                Cerr << "Try '" << Parser_->ProgramName_ << " --help' for more information." << Endl;
+                std::cerr << "Try '" << Parser_->ProgramName_ << " --help' for more information." << std::endl;
             } else {
                 PrintUsage();
             }
diff --git a/library/cpp/getopt/small/modchooser.cpp b/library/cpp/getopt/small/modchooser.cpp
index 03a6e31484b..e94f0223090 100644
--- a/library/cpp/getopt/small/modchooser.cpp
+++ b/library/cpp/getopt/small/modchooser.cpp
@@ -8,6 +8,8 @@
 #include <util/folder/path.h>
 #include <util/string/escape.h>
 
+#include <iostream>
+
 class PtrWrapper: public TMainClass {
 public:
     explicit PtrWrapper(const TMainFunctionPtr& main)
@@ -194,7 +196,7 @@ int TModChooser::Run(const int argc, const char** argv) const {
     }
 
     if (modeIter == Modes.end()) {
-        Cerr << "Unknown mode " << NUtils::Quote(modeName) << "." << Endl;
+        std::cerr << "Unknown mode " << NUtils::Quote(modeName) << "." << std::endl;
         PrintHelp(argv[0], true);
         return 1;
     }
@@ -276,12 +278,12 @@ std::string TModChooser::TMode::FormatFullName(size_t pad) const {
 
 void TModChooser::PrintHelp(const std::string& progName, bool toStdErr) const {
     auto baseName = TFsPath(progName).Basename();
-    auto& out = toStdErr ? Cerr : Cout;
+    auto& out = toStdErr ? std::cerr : std::cout;
     const auto& colors = toStdErr ? NColorizer::StdErr() : NColorizer::StdOut();
-    out << Description << Endl << Endl;
-    out << colors.BoldColor() << "Usage" << colors.OldColor() << ": " << baseName << " MODE [MODE_OPTIONS]" << Endl;
-    out << Endl;
-    out << colors.BoldColor() << "Modes" << colors.OldColor() << ":" << Endl;
+    out << Description << std::endl << std::endl;
+    out << colors.BoldColor() << "Usage" << colors.OldColor() << ": " << baseName << " MODE [MODE_OPTIONS]" << std::endl;
+    out << std::endl;
+    out << colors.BoldColor() << "Modes" << colors.OldColor() << ":" << std::endl;
     size_t maxModeLen = 0;
     for (const auto& [name, mode] : Modes) {
         if (name != mode->Name)
@@ -293,10 +295,10 @@ void TModChooser::PrintHelp(const std::string& progName, bool toStdErr) const {
         for (const auto& unsortedMode : UnsortedModes)
             if (!unsortedMode->Hidden) {
                 if (unsortedMode->Name.size()) {
-                    out << "  " << unsortedMode->FormatFullName(maxModeLen + 4) << unsortedMode->Description << Endl;
+                    out << "  " << unsortedMode->FormatFullName(maxModeLen + 4) << unsortedMode->Description << std::endl;
                 } else {
-                    out << SeparationString << Endl;
-                    out << unsortedMode->Description << Endl;
+                    out << SeparationString << std::endl;
+                    out << unsortedMode->Description << std::endl;
                 }
             }
     } else {
@@ -305,17 +307,17 @@ void TModChooser::PrintHelp(const std::string& progName, bool toStdErr) const {
                 continue;  // this is an alias
 
             if (!mode.second->Hidden) {
-                out << "  " << mode.second->FormatFullName(maxModeLen + 4) << mode.second->Description << Endl;
+                out << "  " << mode.second->FormatFullName(maxModeLen + 4) << mode.second->Description << std::endl;
             }
         }
     }
 
-    out << Endl;
-    out << "To get help for specific mode type '" << baseName << " MODE " << ModesHelpOption << "'" << Endl;
+    out << std::endl;
+    out << "To get help for specific mode type '" << baseName << " MODE " << ModesHelpOption << "'" << std::endl;
     if (VersionHandler)
-        out << "To print program version type '" << baseName << " --version'" << Endl;
+        out << "To print program version type '" << baseName << " --version'" << std::endl;
     if (!SvnRevisionOptionDisabled) {
-        out << "To print svn revision type '" << baseName << " --svnrevision'" << Endl;
+        out << "To print svn revision type '" << baseName << " --svnrevision'" << std::endl;
     }
 }
 
diff --git a/library/cpp/getopt/small/opt.cpp b/library/cpp/getopt/small/opt.cpp
index 73ff2a582c5..51c20e06a3f 100644
--- a/library/cpp/getopt/small/opt.cpp
+++ b/library/cpp/getopt/small/opt.cpp
@@ -4,6 +4,8 @@
 
 #include <ctype.h>
 
+#include <iostream>
+
 using namespace NLastGetopt;
 
 namespace {
@@ -83,7 +85,7 @@ int Opt::Get(int* longOptionIndex) {
     } catch (const NLastGetopt::TException&) {
         GotError_ = true;
         if (Err)
-            Cerr << CurrentExceptionMessage() << Endl;
+            std::cerr << CurrentExceptionMessage() << std::endl;
         return '?';
     }
 }
diff --git a/library/cpp/http/fetch/httpfsm_ut.cpp b/library/cpp/http/fetch/httpfsm_ut.cpp
index 6d1bb2671a8..bcf6f0fee81 100644
--- a/library/cpp/http/fetch/httpfsm_ut.cpp
+++ b/library/cpp/http/fetch/httpfsm_ut.cpp
@@ -501,7 +501,7 @@ Y_UNIT_TEST_SUITE(TestHttpChunkParser) {
         for (size_t n = 0; n < states.size(); n++) {
             const std::string_view d{blob, n, 1};
             int code = parser.Execute(d.data(), d.size());
-            Cout << std::string(d).Quote() << " " << code << Endl;
+            std::cout << std::string(d).Quote() << " " << code << std::endl;
             UNIT_ASSERT_EQUAL(code, states[n]);
         }
         return parser;
diff --git a/library/cpp/http/fetch/httpparser_ut.cpp b/library/cpp/http/fetch/httpparser_ut.cpp
index 58eca2f8835..8a7af7f4a3f 100644
--- a/library/cpp/http/fetch/httpparser_ut.cpp
+++ b/library/cpp/http/fetch/httpparser_ut.cpp
@@ -39,7 +39,7 @@ namespace {
         // other functions are not really called by THttpParser
         void CheckDocPart(const void* buf, size_t len, THttpHeader* /* header */) {
             std::string s(static_cast<const char*>(buf), len);
-            Cout << "State = " << static_cast<TTestHttpParser*>(this)->GetState() << ", CheckDocPart(" << s.Quote() << ")\n";
+            std::cout << "State = " << static_cast<TTestHttpParser*>(this)->GetState() << ", CheckDocPart(" << s.Quote() << ")\n";
             Body_ += s;
         }
     };
@@ -138,7 +138,7 @@ Y_UNIT_TEST_SUITE(TestHttpParser) {
         for (size_t i = 0; i < blob.size(); ++i) {
             const std::string_view d{blob, i, 1};
             parser.Parse((void*)d.data(), d.size());
-            Cout << std::string(d).Quote() << " -> " << parser.GetState() << Endl;
+            std::cout << std::string(d).Quote() << " -> " << parser.GetState() << std::endl;
         }
         AssertPipelineClen(parser, hdr);
         UNIT_ASSERT_EQUAL(parser.Body(), "OK\r\n");
@@ -213,7 +213,7 @@ Y_UNIT_TEST_SUITE(TestHttpParser) {
         for (size_t i = 0; i < blob.size(); ++i) {
             const std::string_view d{blob, i, 1};
             parser.Parse((void*)d.data(), d.size());
-            Cout << std::string(d).Quote() << " -> " << parser.GetState() << Endl;
+            std::cout << std::string(d).Quote() << " -> " << parser.GetState() << std::endl;
             if (blob.size() / 2 - 1 <= i) // last \n sets EOF
                 UNIT_ASSERT_EQUAL(parser.GetState(), parser.hp_eof);
         }
diff --git a/library/cpp/http/io/list_codings/main.cpp b/library/cpp/http/io/list_codings/main.cpp
index 9818d02bdfe..faca8052115 100644
--- a/library/cpp/http/io/list_codings/main.cpp
+++ b/library/cpp/http/io/list_codings/main.cpp
@@ -1,8 +1,9 @@
 #include <library/cpp/http/io/stream.h>
-#include <util/stream/output.h>
+
+#include <iostream>
 
 int main() {
     for (auto codec : SupportedCodings()) {
-        Cout << codec << Endl;
+        std::cout << codec << std::endl;
     }
 }
diff --git a/library/cpp/http/io/stream_ut_medium.cpp b/library/cpp/http/io/stream_ut_medium.cpp
index 9f3340ac776..ffb6d1535d6 100644
--- a/library/cpp/http/io/stream_ut_medium.cpp
+++ b/library/cpp/http/io/stream_ut_medium.cpp
@@ -35,7 +35,7 @@ Y_UNIT_TEST_SUITE(THttpTestMedium) {
                 UNIT_ASSERT(s.size() > 10);
                 UNIT_ASSERT(s.find(data) == std::string::npos);
             } catch (...) {
-                Cerr << codec << " " << s << Endl;
+                std::cerr << codec << " " << s << std::endl;
 
                 throw;
             }
diff --git a/library/cpp/http/simple/ut/https_ut.cpp b/library/cpp/http/simple/ut/https_ut.cpp
index f448166cada..5f18154ffc5 100644
--- a/library/cpp/http/simple/ut/https_ut.cpp
+++ b/library/cpp/http/simple/ut/https_ut.cpp
@@ -7,6 +7,8 @@
 
 #include <util/system/shellcommand.h>
 
+#include <iostream>
+
 Y_UNIT_TEST_SUITE(Https) {
     using TShellCommandPtr = std::unique_ptr<TShellCommand>;
 
@@ -14,7 +16,7 @@ Y_UNIT_TEST_SUITE(Https) {
         const std::string data = ArcadiaSourceRoot() + "/library/cpp/http/simple/ut/https_server";
 
         const std::string command =
-            TYdbStringBuilder()
+            TStringBuilder()
             << BuildRoot() << "/library/cpp/http/simple/ut/https_server/https_server"
             << " --port " << port
             << " --keyfile " << data << "/http_server.key"
@@ -37,7 +39,7 @@ Y_UNIT_TEST_SUITE(Https) {
                 client.DoGet("/ping");
                 break;
             } catch (const std::exception& e) {
-                Cout << "== failed to connect to new server: " << e.what() << Endl;
+                std::cout << "== failed to connect to new server: " << e.what() << std::endl;
                 Sleep(TDuration::MilliSeconds(1));
             }
         }
@@ -46,7 +48,7 @@ Y_UNIT_TEST_SUITE(Https) {
     }
 
     static void get(TKeepAliveHttpClient & client) {
-        std::stringStream out;
+        TStringStream out;
         ui32 code = 0;
 
         UNIT_ASSERT_NO_EXCEPTION(code = client.DoGet("/ping", &out));
@@ -75,7 +77,7 @@ Y_UNIT_TEST_SUITE(Https) {
     }
 
     static void get(TSimpleHttpClient & client) {
-        std::stringStream out;
+        TStringStream out;
 
         UNIT_ASSERT_NO_EXCEPTION_C(client.DoGet("/ping", &out), out.Str());
         UNIT_ASSERT_VALUES_EQUAL(out.Str(), "pong.my");
diff --git a/library/cpp/json/fuzzy_test/main.cpp b/library/cpp/json/fuzzy_test/main.cpp
index a6e0a7d4376..a5ce20454ba 100644
--- a/library/cpp/json/fuzzy_test/main.cpp
+++ b/library/cpp/json/fuzzy_test/main.cpp
@@ -10,20 +10,20 @@ extern "C" int LLVMFuzzerTestOneInput(const ui8* data, size_t size) {
         NJson::TJsonValue value;
         NJson::ReadJsonFastTree(json, &value, true);
     } catch (...) {
-        //Cout << json << " -> " << CurrentExceptionMessage() << Endl;
+        //std::cout << json << " -> " << CurrentExceptionMessage() << std::endl;
     }
 
     try {
         NJson::TJsonCallbacks cb;
         NJson::ReadJsonFast(json, &cb);
     } catch (...) {
-        //Cout << json << " -> " << CurrentExceptionMessage() << Endl;
+        //std::cout << json << " -> " << CurrentExceptionMessage() << std::endl;
     }
 
     try {
         NJson::ValidateJson(json);
     } catch (...) {
-        //Cout << json << " -> " << CurrentExceptionMessage() << Endl;
+        //std::cout << json << " -> " << CurrentExceptionMessage() << std::endl;
     }
 
     return 0;
diff --git a/library/cpp/json/ut/json_reader_fast_ut.cpp b/library/cpp/json/ut/json_reader_fast_ut.cpp
index ee95ea99db0..7ba5b265bc9 100644
--- a/library/cpp/json/ut/json_reader_fast_ut.cpp
+++ b/library/cpp/json/ut/json_reader_fast_ut.cpp
@@ -5,6 +5,8 @@
 #include <library/cpp/string_utils/relaxed_escaper/relaxed_escaper.h>
 #include <util/string/cast.h>
 
+#include <iostream>
+
 namespace NJson {
     namespace NTest {
         enum ETestEvent {
@@ -157,9 +159,9 @@ namespace NJson {
                         UNIT_ASSERT_VALUES_EQUAL_C(e[i].Str, Events[i].Str, std::format("'{}' {}", str, i));
                     }
                 } catch (const yexception&) {
-                    Clog << "Exception at '" << str << "'" << Endl;
+                    std::cerr << "Exception at '" << str << "'" << std::endl;
                     for (const auto& event : Events) {
-                        Clog << event.ToString() << Endl;
+                        std::cerr << event.ToString() << std::endl;
                     }
 
                     throw;
diff --git a/library/cpp/json/writer/README.md b/library/cpp/json/writer/README.md
index a20489f32ee..0986cf62c81 100644
--- a/library/cpp/json/writer/README.md
+++ b/library/cpp/json/writer/README.md
@@ -10,7 +10,7 @@ Use it like this:
     json.BeginList()
         .WriteString("<script>")
         .EndList();
-    Cout << json.Str(); // output: ["\u003Cscript\u003E"]
+    std::cout << json.Str(); // output: ["\u003Cscript\u003E"]
 
 For compatibility with legacy formats where object keys
 are not quoted, use CompatWriteKeyWithoutQuotes:
@@ -20,4 +20,4 @@ are not quoted, use CompatWriteKeyWithoutQuotes:
         .CompatWriteKeyWithoutQuotes("r").WriteInt(1)
         .CompatWriteKeyWithoutQuotes("n").WriteInt(0)
     .EndObject();
-    Cout << json.Str(); // output: {r:1,n:0}
+    std::cout << json.Str(); // output: {r:1,n:0}
diff --git a/library/cpp/logger/log_ut.cpp b/library/cpp/logger/log_ut.cpp
index 25ebadd2b00..8de6cfa82a9 100644
--- a/library/cpp/logger/log_ut.cpp
+++ b/library/cpp/logger/log_ut.cpp
@@ -153,7 +153,7 @@ void TLogTest::TestNoFlush() {
 }
 
 void TLogTest::TestFormat() {
-    std::stringStream data;
+    TStringStream data;
 
     {
         TLog log(THolder(new TStreamLogBackend(&data)));
@@ -167,7 +167,7 @@ void TLogTest::TestFormat() {
 }
 
 void TLogTest::TestWrite() {
-    std::stringStream data;
+    TStringStream data;
     std::string test;
 
     {
diff --git a/library/cpp/monlib/dynamic_counters/percentile/percentile_ut.cpp b/library/cpp/monlib/dynamic_counters/percentile/percentile_ut.cpp
index 0f01b1642b4..a6e979340f9 100644
--- a/library/cpp/monlib/dynamic_counters/percentile/percentile_ut.cpp
+++ b/library/cpp/monlib/dynamic_counters/percentile/percentile_ut.cpp
@@ -3,6 +3,8 @@
 #include <library/cpp/testing/unittest/registar.h>
 #include <util/datetime/cputimer.h>
 
+#include <iostream>
+
 using namespace NMonitoring;
 
 Y_UNIT_TEST_SUITE(PercentileTest) {
@@ -10,14 +12,14 @@ Y_UNIT_TEST_SUITE(PercentileTest) {
 template<size_t A, size_t B, size_t B_BEGIN>
 void PrintSizeAndLimit() {
     using TPerc = TPercentileTrackerLg<A, B, 15>;
-    Cout << "TPercentileTrackerLg<" << A << ", " << B << ", 15>"
+    std::cout << "TPercentileTrackerLg<" << A << ", " << B << ", 15>"
         << "; sizeof# " << LeftPad(HumanReadableSize(sizeof(TPerc), SF_BYTES), 7)
         << "; max_granularity# " << LeftPad(HumanReadableSize(TPerc::MAX_GRANULARITY, SF_QUANTITY), 5)
-        << "; limit# " << LeftPad(HumanReadableSize(TPerc::TRACKER_LIMIT , SF_QUANTITY), 5) << Endl;
+        << "; limit# " << LeftPad(HumanReadableSize(TPerc::TRACKER_LIMIT , SF_QUANTITY), 5) << std::endl;
     if constexpr (B > 1) {
         PrintSizeAndLimit<A, B - 1, B_BEGIN>();
     } else if constexpr (A > 1) {
-        Cout << Endl;
+        std::cout << std::endl;
         PrintSizeAndLimit<A - 1, B_BEGIN, B_BEGIN>();
     }
 }
diff --git a/library/cpp/monlib/encode/json/json_ut.cpp b/library/cpp/monlib/encode/json/json_ut.cpp
index 79fe580fb26..47671f3b6e9 100644
--- a/library/cpp/monlib/encode/json/json_ut.cpp
+++ b/library/cpp/monlib/encode/json/json_ut.cpp
@@ -42,7 +42,7 @@ namespace {
 
         if (diff.size() > 0) {
             for (auto&& l : diff) {
-                Cerr << l << Endl;
+                std::cerr << l << std::endl;
             }
 
             UNIT_FAIL("Labels don't match");
diff --git a/library/cpp/monlib/encode/spack/spack_v1_ut.cpp b/library/cpp/monlib/encode/spack/spack_v1_ut.cpp
index be7e0b46ac2..4296799b0d9 100644
--- a/library/cpp/monlib/encode/spack/spack_v1_ut.cpp
+++ b/library/cpp/monlib/encode/spack/spack_v1_ut.cpp
@@ -366,8 +366,8 @@ Y_UNIT_TEST_SUITE(TSpackTest) {
         e->OnStreamEnd();
         e->Close();
 
-        // Cout << "encoded: " << HexEncode(buffer.Data(), buffer.Size()) << Endl;
-        // Cout << "size: " << buffer.Size() << Endl;
+        // std::cout << "encoded: " << HexEncode(buffer.Data(), buffer.Size()) << std::endl;
+        // std::cout << "size: " << buffer.Size() << std::endl;
 
         UNIT_ASSERT_VALUES_EQUAL(buffer.Size(), expectedSize);
 
diff --git a/library/cpp/resource/README.md b/library/cpp/resource/README.md
index b1e4961c1fe..99aedbd72ed 100644
--- a/library/cpp/resource/README.md
+++ b/library/cpp/resource/README.md
@@ -18,7 +18,7 @@ END()
 ```cpp
 #include <library/cpp/resource/resource.h>
 int main() {
-        Cout << NResource::Find("/key/in/program/1") << Endl;
-        Cout << NResource::Find("/key2") << Endl;
+        std::cout << NResource::Find("/key/in/program/1") << std::endl;
+        std::cout << NResource::Find("/key2") << std::endl;
 }
 ```
diff --git a/library/cpp/resource/registry.cpp b/library/cpp/resource/registry.cpp
index 6d64510a398..af8648aced2 100644
--- a/library/cpp/resource/registry.cpp
+++ b/library/cpp/resource/registry.cpp
@@ -9,6 +9,8 @@
 #include <util/generic/singleton.h>
 #include <util/string/escape.h>
 
+#include <iostream>
+
 using namespace NResource;
 using namespace NBlockCodecs;
 
@@ -62,7 +64,7 @@ namespace {
                     *out = Decompress((*res)->second);
                 } catch (const yexception& e) {
                     if (!std::string{std::getenv("RESOURCE_DECOMPRESS_DIAG") ? std::getenv("RESOURCE_DECOMPRESS_DIAG") : ""}.empty()) {
-                        Cerr << "Can't decompress resource " << key << Endl << e.what() << Endl;
+                        std::cerr << "Can't decompress resource " << key << std::endl << e.what() << std::endl;
                     }
                     throw e;
                 }
@@ -84,7 +86,7 @@ namespace {
                         cb.OnMatch(res);
                     } catch (const yexception& e) {
                         if (!std::string{getenv("RESOURCE_DECOMPRESS_DIAG")}.empty()) {
-                            Cerr << "Can't decompress resource " << it.first << Endl << e.what() << Endl;
+                            std::cerr << "Can't decompress resource " << it.first << std::endl << e.what() << std::endl;
                         }
                         throw e;
                     }
diff --git a/library/cpp/terminate_handler/sample/rethrow/main.cpp b/library/cpp/terminate_handler/sample/rethrow/main.cpp
index fcd8592613a..9b94be7adc8 100644
--- a/library/cpp/terminate_handler/sample/rethrow/main.cpp
+++ b/library/cpp/terminate_handler/sample/rethrow/main.cpp
@@ -9,7 +9,7 @@ void Foo() {
     try {
         Bar();
     } catch (...) {
-        Cerr << "caught; rethrowing\n";
+        std::cerr << "caught; rethrowing\n";
         throw;
     }
 }
diff --git a/library/cpp/terminate_handler/terminate_handler.cpp b/library/cpp/terminate_handler/terminate_handler.cpp
index d159c9a5ca2..ae93ff73686 100644
--- a/library/cpp/terminate_handler/terminate_handler.cpp
+++ b/library/cpp/terminate_handler/terminate_handler.cpp
@@ -5,6 +5,7 @@
 #include <util/system/backtrace.h>
 #include <util/generic/yexception.h>
 
+#include <iostream>
 #include <string>
 
 namespace {
@@ -17,7 +18,7 @@ namespace {
             case 1:
                 break;
             case 2:
-                Cerr << "FancyTerminateHandler called recursively" << Endl;
+                std::cerr << "FancyTerminateHandler called recursively" << std::endl;
                 [[fallthrough]];
             default:
                 abort();
@@ -25,12 +26,12 @@ namespace {
         }
 
         if (std::current_exception()) {
-            Cerr << "Uncaught exception: " << CurrentExceptionMessage() << '\n';
+            std::cerr << "Uncaught exception: " << CurrentExceptionMessage() << '\n';
         } else {
-            Cerr << "Terminate for unknown reason (no current exception)\n";
+            std::cerr << "Terminate for unknown reason (no current exception)\n";
         }
         PrintBackTrace();
-        Cerr.Flush();
+        std::cerr.flush();
         abort();
     }
 
diff --git a/library/cpp/testing/gtest/main.cpp b/library/cpp/testing/gtest/main.cpp
index 57fea720995..62f90b924b4 100644
--- a/library/cpp/testing/gtest/main.cpp
+++ b/library/cpp/testing/gtest/main.cpp
@@ -9,6 +9,7 @@
 #include <util/system/src_root.h>
 
 #include <fstream>
+#include <iostream>
 
 namespace {
     bool StartsWith(const char* str, const char* pre) {
@@ -87,10 +88,10 @@ namespace {
             // result in calling `fflush(stderr)`. However, there may be additional buffering logic
             // going on (custom `std::cerr.tie()`, for example), so just to be sure, we flush both of them.
             std::cout << std::flush;
-            Cout << marker << Flush;
+            std::cout << marker << std::flush;
 
             std::cerr << std::flush;
-            Cerr << marker << Flush;
+            std::cerr << marker << std::flush;
 
             auto ts = std::chrono::duration_cast<std::chrono::duration<double>>(
                 std::chrono::system_clock::now().time_since_epoch());
@@ -195,10 +196,10 @@ namespace {
             auto marker = Join("", "\n###subtest-finished:", testInfo.test_suite_name(), "::", testInfo.name(), "\n");
 
             std::cout << std::flush;
-            Cout << marker << Flush;
+            std::cout << marker << std::flush;
 
             std::cerr << std::flush;
-            Cerr << marker << Flush;
+            std::cerr << marker << std::flush;
 
             PrintTestStatus(testInfo, status, messages.str(), properties, ts);
         }
diff --git a/library/cpp/testing/gtest/matchers.cpp b/library/cpp/testing/gtest/matchers.cpp
index 0f2be4762be..4a27123efc1 100644
--- a/library/cpp/testing/gtest/matchers.cpp
+++ b/library/cpp/testing/gtest/matchers.cpp
@@ -6,12 +6,14 @@
 #include <util/stream/file.h>
 #include <util/system/fs.h>
 
+#include <iostream>
+
 bool NGTest::NDetail::MatchOrUpdateGolden(std::string_view actualContent, const std::string& goldenFilename) {
     if (!GetTestParam("GTEST_UPDATE_GOLDEN").empty()) {
         Y_ENSURE(NFs::MakeDirectoryRecursive(TFsPath(goldenFilename).Parent()));
         TFile file(goldenFilename, CreateAlways);
         file.Write(actualContent.data(), actualContent.size());
-        Cerr << "The data[" << actualContent.size() << "] has written to golden file " << goldenFilename << Endl;
+        std::cerr << "The data[" << actualContent.size() << "] has written to golden file " << goldenFilename << std::endl;
         return true;
     }
 
diff --git a/library/cpp/testing/gtest/ut/ut.cpp b/library/cpp/testing/gtest/ut/ut.cpp
index 0b6d69b2cfa..61b1534b208 100644
--- a/library/cpp/testing/gtest/ut/ut.cpp
+++ b/library/cpp/testing/gtest/ut/ut.cpp
@@ -1,6 +1,8 @@
 #include <library/cpp/testing/gtest/gtest.h>
 #include <library/cpp/testing/hook/hook.h>
 
+#include <iostream>
+
 static int HookOrder = 0;
 static int PreInitHook1 = 0;
 static int PreInitHook2 = 0;
@@ -27,12 +29,12 @@ Y_TEST_HOOK_BEFORE_RUN(PreRun2) {
 
 Y_TEST_HOOK_AFTER_RUN(PostRun1) {
     PostRunHook1 = ++HookOrder;
-    Cerr << "PostRunHook1" << Endl;
+    std::cerr << "PostRunHook1" << std::endl;
 }
 
 Y_TEST_HOOK_AFTER_RUN(PostRun2) {
     PostRunHook2 = ++HookOrder;
-    Cerr << "PostRunHook2" << Endl;
+    std::cerr << "PostRunHook2" << std::endl;
 }
 
 TEST(Gtest, HookOrder) {
diff --git a/library/cpp/testing/unittest/junit.cpp b/library/cpp/testing/unittest/junit.cpp
index e94866a73ac..56f1a3680db 100644
--- a/library/cpp/testing/unittest/junit.cpp
+++ b/library/cpp/testing/unittest/junit.cpp
@@ -17,6 +17,8 @@
 #include <util/system/fstat.h>
 #include <util/system/tempfile.h>
 
+#include <iostream>
+
 #include <stdio.h>
 #include <signal.h>
 
@@ -128,7 +130,7 @@ struct TJUnitProcessor::TOutputCapturer {
             try {
                 constexpr size_t LIMIT = 10_KB;
                 constexpr size_t PART_LIMIT = 5_KB;
-                TYdbStringBuilder out;
+                TStringBuilder out;
                 if (static_cast<size_t>(len) <= LIMIT) {
                     out.resize(len);
                     captured.Read((void*)out.data(), len);
@@ -167,7 +169,7 @@ struct TJUnitProcessor::TOutputCapturer {
                 }
                 return std::move(out);
             } catch (const std::exception& ex) {
-                Cerr << "Failed to read from captured output: " << ex.what() << Endl;
+                std::cerr << "Failed to read from captured output: " << ex.what() << std::endl;
             }
         }
         return {};
@@ -289,7 +291,7 @@ void TJUnitProcessor::MakeReportFileName() {
     }
 
     if (ResultReportFileName.empty()) {
-        Cerr << "Could not find a vacant file name to write report for path " << FileName << ", maximum number of reports: " << MaxReps << Endl;
+        std::cerr << "Could not find a vacant file name to write report for path " << FileName << ", maximum number of reports: " << MaxReps << std::endl;
         Y_ABORT("Cannot write report");
     }
 }
@@ -646,7 +648,7 @@ void TJUnitProcessor::MergeSubprocessReport() {
     {
         const i64 len = GetFileLength(TmpReportFile->Name());
         if (len < 0) {
-            Cerr << "Failed to get length of the output file for subprocess" << Endl;
+            std::cerr << "Failed to get length of the output file for subprocess" << std::endl;
             return;
         }
         if (len == 0) {
@@ -663,66 +665,66 @@ void TJUnitProcessor::MergeSubprocessReport() {
     {
         TFileInput in(TmpReportFile->Name());
         if (!NJson::ReadJsonTree(&in, &testsReportJson)) {
-            Cerr << "Failed to read json report for subprocess" << Endl;
+            std::cerr << "Failed to read json report for subprocess" << std::endl;
             return;
         }
     }
 
     if (!testsReportJson.IsMap()) {
-        Cerr << "Invalid subprocess report format: report is not a map" << Endl;
+        std::cerr << "Invalid subprocess report format: report is not a map" << std::endl;
         return;
     }
 
     const NJson::TJsonValue* testSuitesJson = nullptr;
     if (!testsReportJson.GetValuePointer("testsuites"sv, &testSuitesJson)) {
         // no tests for some reason
-        Cerr << "No tests found in subprocess report" << Endl;
+        std::cerr << "No tests found in subprocess report" << std::endl;
         return;
     }
 
     if (!testSuitesJson->IsArray()) {
-        Cerr << "Invalid subprocess report format: testsuites is not an array" << Endl;
+        std::cerr << "Invalid subprocess report format: testsuites is not an array" << std::endl;
         return;
     }
 
     for (const NJson::TJsonValue& suiteJson : testSuitesJson->GetArray()) {
         if (!suiteJson.IsMap()) {
-            Cerr << "Invalid subprocess report format: suite is not a map" << Endl;
+            std::cerr << "Invalid subprocess report format: suite is not a map" << std::endl;
             continue;
         }
         const NJson::TJsonValue* suiteIdJson = nullptr;
         if (!suiteJson.GetValuePointer("id"sv, &suiteIdJson)) {
-            Cerr << "Invalid subprocess report format: suite does not have id" << Endl;
+            std::cerr << "Invalid subprocess report format: suite does not have id" << std::endl;
             continue;
         }
 
         const std::string& suiteId = suiteIdJson->GetString();
         if (suiteId.empty()) {
-            Cerr << "Invalid subprocess report format: suite has empty id" << Endl;
+            std::cerr << "Invalid subprocess report format: suite has empty id" << std::endl;
             continue;
         }
 
         TTestSuite& suiteInfo = Suites[suiteId];
         const NJson::TJsonValue* testCasesJson = nullptr;
         if (!suiteJson.GetValuePointer("testcases"sv, &testCasesJson)) {
-            Cerr << "No test cases found in suite \"" << suiteId << "\"" << Endl;
+            std::cerr << "No test cases found in suite \"" << suiteId << "\"" << std::endl;
             continue;
         }
         if (!testCasesJson->IsArray()) {
-            Cerr << "Invalid subprocess report format: testcases value is not an array" << Endl;
+            std::cerr << "Invalid subprocess report format: testcases value is not an array" << std::endl;
             continue;
         }
 
         for (const NJson::TJsonValue& testCaseJson : testCasesJson->GetArray()) {
             const NJson::TJsonValue* testCaseIdJson = nullptr;
             if (!testCaseJson.GetValuePointer("id"sv, &testCaseIdJson)) {
-                Cerr << "Invalid subprocess report format: test case does not have id" << Endl;
+                std::cerr << "Invalid subprocess report format: test case does not have id" << std::endl;
                 continue;
             }
 
             const std::string& testCaseId = testCaseIdJson->GetString();
             if (testCaseId.empty()) {
-                Cerr << "Invalid subprocess report format: test case has empty id" << Endl;
+                std::cerr << "Invalid subprocess report format: test case has empty id" << std::endl;
                 continue;
             }
 
@@ -749,7 +751,7 @@ void TJUnitProcessor::MergeSubprocessReport() {
             }
 
             if (!failuresJson->IsArray()) {
-                Cerr << "Invalid subprocess report format: failures is not an array" << Endl;
+                std::cerr << "Invalid subprocess report format: failures is not an array" << std::endl;
                 continue;
             }
 
diff --git a/library/cpp/testing/unittest/pytests/test_subject/tests.cpp b/library/cpp/testing/unittest/pytests/test_subject/tests.cpp
index 677e5130edd..6e38696aa75 100644
--- a/library/cpp/testing/unittest/pytests/test_subject/tests.cpp
+++ b/library/cpp/testing/unittest/pytests/test_subject/tests.cpp
@@ -1,10 +1,12 @@
 #include <library/cpp/testing/unittest/registar.h>
 
+#include <iostream>
+
 namespace NSubjectTests {
     class TAlwaysTearDownFixture : public NUnitTest::TBaseFixture {
     public:
         void TearDown(NUnitTest::TTestContext&) override {
-            Cerr << Name_ << ": TearDown is ran" << Endl;
+            std::cerr << Name_ << ": TearDown is ran" << std::endl;
         }
     };
 
@@ -15,7 +17,7 @@ namespace NSubjectTests {
         }
 
         void TearDown(NUnitTest::TTestContext&) override {
-            Cerr << Name_ << ": TearDown is ran" << Endl;
+            std::cerr << Name_ << ": TearDown is ran" << std::endl;
         }
     };
 
diff --git a/library/cpp/testing/unittest/utmain.cpp b/library/cpp/testing/unittest/utmain.cpp
index e4f13fa2530..887567ad63f 100644
--- a/library/cpp/testing/unittest/utmain.cpp
+++ b/library/cpp/testing/unittest/utmain.cpp
@@ -32,6 +32,7 @@
 #include <util/system/shellcommand.h>
 
 #include <filesystem>
+#include <iostream>
 
 #if defined(_win_)
     #include <fcntl.h>
@@ -163,11 +164,11 @@ class TTraceWriterProcessor: public ITestSuiteProcessor {
 
         PrevTime = now;
         std::string marker = Join("", "\n###subtest-finished:", className, "::", subtestName, "\n");
-        Cout << marker;
-        Cout.Flush();
-        Cerr << comment;
-        Cerr << marker;
-        Cerr.Flush();
+        std::cout << marker;
+        std::cout.Flush();
+        std::cerr << comment;
+        std::cerr << marker;
+        std::cerr.Flush();
     }
 
     virtual std::string BuildComment(const char* message, const char* backTrace) {
@@ -186,10 +187,10 @@ class TTraceWriterProcessor: public ITestSuiteProcessor {
         event.InsertValue("subtest", test->name);
         Trace("subtest-started", event);
         std::string marker = Join("", "\n###subtest-started:", test->unit->name, "::", test->name, "\n");
-        Cout << marker;
-        Cout.Flush();
-        Cerr << marker;
-        Cerr.Flush();
+        std::cout << marker;
+        std::cout.flush();
+        std::cerr << marker;
+        std::cerr.flush();
     }
 
     void OnUnitStart(const TUnit* unit) override {
@@ -455,7 +456,7 @@ class TColoredProcessor: public ITestSuiteProcessor, public NColorizer::TColors
             return;
         }
 
-        Cerr << d << "\n";
+        std::cerr << d.ToString() << "\n";
     }
 
     void OnEnd() override {
@@ -547,8 +548,8 @@ class TColoredProcessor: public ITestSuiteProcessor, public NColorizer::TColors
         ForkExitedCorrectly = msgIndex != std::string::npos;
 
         // TODO: stderr output is always printed after stdout
-        Cout.Write(cmd.GetOutput());
-        Cerr.Write(err.c_str(), Min(msgIndex, err.size()));
+        std::cout << cmd.GetOutput();
+        std::cerr.write(err.c_str(), Min(msgIndex, err.size()));
 
         // do not use default case, so gcc will warn if new element in enum will be added
         switch (cmd.GetStatus()) {
@@ -670,20 +671,21 @@ static int DoList(bool verbose, IOutputStream& stream) {
 }
 
 static int DoUsage(const char* progname) {
-    Cout << "Usage: " << progname << " [options] [[+|-]test]...\n\n"
-         << "Options:\n"
-         << "  -h, --help            print this help message\n"
-         << "  -l, --list            print a list of available tests\n"
-         << "  -A --list-verbose        print a list of available subtests\n"
-         << "  --print-before-test   print each test name before running it\n"
-         << "  --print-before-suite  print each test suite name before running it\n"
-         << "  --show-fails          print a list of all failed tests at the end\n"
-         << "  --dont-show-fails     do not print a list of all failed tests at the end\n"
-         << "  --print-times         print wall clock duration of each test\n"
-         << "  --fork-tests          run each test in a separate process\n"
-         << "  --trace-path          path to the trace file to be generated\n"
-         << "  --trace-path-append   path to the trace file to be appended\n"
-         << "  --filter-file         path to the test filters ([+|-]test) file (" << Y_UNITTEST_TEST_FILTER_FILE_OPTION << ")\n";
+    std::cout << "Usage: " << progname << " [options] [[+|-]test]...\n\n"
+              << "Options:\n"
+              << "  -h, --help            print this help message\n"
+              << "  -l, --list            print a list of available tests\n"
+              << "  -A --list-verbose        print a list of available subtests\n"
+              << "  --print-before-test   print each test name before running it\n"
+              << "  --print-before-suite  print each test suite name before running it\n"
+              << "  --show-fails          print a list of all failed tests at the end\n"
+              << "  --dont-show-fails     do not print a list of all failed tests at the end\n"
+              << "  --print-times         print wall clock duration of each test\n"
+              << "  --fork-tests          run each test in a separate process\n"
+              << "  --trace-path          path to the trace file to be generated\n"
+              << "  --trace-path-append   path to the trace file to be appended\n"
+              << "  --filter-file         path to the test filters ([+|-]test) file (" 
+              << Y_UNITTEST_TEST_FILTER_FILE_OPTION << ")\n";
     return 0;
 }
 
@@ -871,7 +873,7 @@ int NUnitTest::RunMain(int argc, char** argv) {
         for (;;) {
             ret = TTestFactory::Instance().Execute();
             if (!processor.GetIsForked() && ret && processor.GetPrintSummary()) {
-                Cerr << "SOME TESTS FAILED!!!!" << Endl;
+                std::cerr << "SOME TESTS FAILED!!!!" << std::endl;
             }
 
             if (0 != ret || !processor.IsLoop()) {
@@ -881,7 +883,7 @@ int NUnitTest::RunMain(int argc, char** argv) {
         return ret;
 #ifndef UT_SKIP_EXCEPTIONS
     } catch (...) {
-        Cerr << "caught exception in test suite(" << CurrentExceptionMessage() << ")" << Endl;
+        std::cerr << "caught exception in test suite(" << CurrentExceptionMessage() << ")" << std::endl;
     }
 #endif
 
diff --git a/library/cpp/yt/memory/unittests/free_list_ut.cpp b/library/cpp/yt/memory/unittests/free_list_ut.cpp
index 3d2ecf103ef..fedf5f1a10a 100644
--- a/library/cpp/yt/memory/unittests/free_list_ut.cpp
+++ b/library/cpp/yt/memory/unittests/free_list_ut.cpp
@@ -139,8 +139,8 @@ TEST_P(TFreeListStressTest, Stress)
         worker.join();
     }
 
-    Cerr << "Put: " << put.load() << Endl;
-    Cerr << "Extracted: " << extracted.load() << Endl;
+    std::cerr << "Put: " << put.load() << std::endl;
+    std::cerr << "Extracted: " << extracted.load() << std::endl;
     EXPECT_EQ(put.load(), extracted.load());
 }
 
diff --git a/tools/enum_parser/enum_parser/main.cpp b/tools/enum_parser/enum_parser/main.cpp
index 7c5180c07f7..0a45484ee8c 100644
--- a/tools/enum_parser/enum_parser/main.cpp
+++ b/tools/enum_parser/enum_parser/main.cpp
@@ -23,6 +23,8 @@
 #include <util/system/fs.h>
 #include <util/folder/path.h>
 
+#include <iostream>
+
 void WriteHeader(const std::string& headerName, IOutputStream& out, IOutputStream* headerOutPtr = nullptr) {
     out << "// This file was auto-generated. Do not edit!!!\n";
     out << "#include " << headerName << "\n";
@@ -452,16 +454,16 @@ int main(int argc, char** argv) {
         THolder<IOutputStream> jsonOut;
 
         if (!outputFileName.empty()) {
-            NFs::Remove(outputFileName.c_str());
-            hOut.Reset(new TFileOutput(outputFileName.c_str()));
+            NFs::Remove(outputFileName);
+            hOut.Reset(new TFileOutput(outputFileName));
             out = hOut.Get();
 
             if (!outputHeaderFileName.empty()) {
-                headerOut.Reset(new TFileOutput(outputHeaderFileName.c_str()));
+                headerOut.Reset(new TFileOutput(outputHeaderFileName));
             }
 
             if (!outputJsonFileName.empty()) {
-                jsonOut.Reset(new TFileOutput(outputJsonFileName.c_str()));
+                jsonOut.Reset(new TFileOutput(outputJsonFileName));
             }
         }
 
@@ -496,7 +498,7 @@ int main(int argc, char** argv) {
 
         return 0;
     } catch (...) {
-        Cerr << CurrentExceptionMessage() << Endl;
+        std::cerr << CurrentExceptionMessage() << std::endl;
     }
 
     return 1;
diff --git a/tools/enum_parser/parse_enum/parse_enum.cpp b/tools/enum_parser/parse_enum/parse_enum.cpp
index 2988d7780de..959df74674e 100644
--- a/tools/enum_parser/parse_enum/parse_enum.cpp
+++ b/tools/enum_parser/parse_enum/parse_enum.cpp
@@ -6,6 +6,8 @@
 #include <util/stream/file.h>
 #include <util/string/escape.h>
 
+#include <iostream>
+
 /**
  * Parse C-style strings inside multiline comments
  **/
@@ -323,7 +325,7 @@ class TCppContext: public TCppFullSax {
 
     // Some debug stuff goes here
     static void PrintScope(const TScope& scope) {
-        Cerr << "Current scope: " << TEnumParser::ScopeStr(scope) << Endl;
+        std::cerr << "Current scope: " << TEnumParser::ScopeStr(scope) << std::endl;
     }
 
     void PrintScope() {
@@ -331,14 +333,14 @@ class TCppContext: public TCppFullSax {
     }
 
     void PrintEnum(const TEnum& en) {
-        Cerr << "Enum within scope " << NUtils::Quote(TEnumParser::ScopeStr(en.Scope)) << Endl;
+        std::cerr << "Enum within scope " << NUtils::Quote(TEnumParser::ScopeStr(en.Scope)) << std::endl;
         for (const auto& item : en.Items) {
-            Cerr << "    " << item.CppName;
+            std::cerr << "    " << item.CppName;
             if (item.Value)
-                Cerr << " = " << *item.Value;
-            Cerr << Endl;
+                std::cerr << " = " << *item.Value;
+            std::cerr << std::endl;
             for (const auto& value : item.Aliases) {
-                Cerr << "        " << value << Endl;
+                std::cerr << "        " << value << std::endl;
             }
         }
     }
diff --git a/tools/rescompiler/main.cpp b/tools/rescompiler/main.cpp
index b43158d7626..6f002c1272f 100644
--- a/tools/rescompiler/main.cpp
+++ b/tools/rescompiler/main.cpp
@@ -8,6 +8,8 @@
 #include <util/string/vector.h>
 #include <util/string/split.h>
 
+#include <iostream>
+
 using namespace NResource;
 
 static inline void GenOne(const std::string& data, const std::string& key, IOutputStream& out) {
@@ -33,7 +35,7 @@ static inline void GenOne(const std::string& data, const std::string& key, IOutp
 
 int main(int argc, char** argv) {
     if ((argc < 4) || (argc % 2)) {
-        Cerr << "usage: " << argv[0] << " outfile [infile path]+ [- key=value]+" << Endl;
+        std::cerr << "usage: " << argv[0] << " outfile [infile path]+ [- key=value]+" << std::endl;
 
         return 1;
     }
diff --git a/util/datetime/cputimer.cpp b/util/datetime/cputimer.cpp
index a0cbb16261c..bd713473dc2 100644
--- a/util/datetime/cputimer.cpp
+++ b/util/datetime/cputimer.cpp
@@ -6,6 +6,7 @@
 #include <util/generic/singleton.h>
 
 #include <format>
+#include <iostream>
 
 #if defined(_unix_)
     #include <unistd.h>
@@ -25,7 +26,7 @@ TTimer::TTimer(const std::string_view message) {
 TTimer::~TTimer() {
     const TDuration duration = TInstant::Now() - Start_;
     Message_ << duration << "\n";
-    Cerr << Message_.Str();
+    std::cerr << Message_.Str();
 }
 
 static ui64 ManuallySetCyclesPerSecond = 0;
@@ -109,11 +110,11 @@ TFuncTimer::TFuncTimer(const char* func)
     : Start_(TInstant::Now())
     , Func_(func)
 {
-    Cerr << "enter " << Func_ << Endl;
+    std::cerr << "enter " << Func_ << std::endl;
 }
 
 TFuncTimer::~TFuncTimer() {
-    Cerr << "leave " << Func_ << " -> " << (TInstant::Now() - Start_) << Endl;
+    std::cerr << "leave " << Func_ << " -> " << (TInstant::Now() - Start_).ToString() << std::endl;
 }
 
 TTimeLogger::TTimeLogger(const std::string& message, bool verbose)
diff --git a/util/folder/path_ut.cpp b/util/folder/path_ut.cpp
index 00fa627cea7..498178f7c2f 100644
--- a/util/folder/path_ut.cpp
+++ b/util/folder/path_ut.cpp
@@ -618,7 +618,7 @@ Y_UNIT_TEST_SUITE(TFsPathTests) {
                 Chmod(Name_.c_str(), MODE0777);
                 SetAcl((PACL)Acl_.Get(), GRANT_ACCESS);
             } catch (const yexception& ex) {
-                Cerr << "~TWinFileDenyAccessScope failed: " << ex.AsStrBuf() << Endl;
+                std::cerr << "~TWinFileDenyAccessScope failed: " << ex.AsStrBuf() << std::endl;
             }
         }
 
diff --git a/util/generic/mapfindptr.h b/util/generic/mapfindptr.h
index bb6dc617552..1dc61625bf0 100644
--- a/util/generic/mapfindptr.h
+++ b/util/generic/mapfindptr.h
@@ -8,7 +8,7 @@
 /** MapFindPtr usage:
 
 if (T* value = MapFindPtr(myMap, someKey) {
-    Cout << *value;
+    std::cout << *value;
 }
 
 */
diff --git a/util/generic/object_counter.h b/util/generic/object_counter.h
index 57617101eea..624323729ec 100644
--- a/util/generic/object_counter.h
+++ b/util/generic/object_counter.h
@@ -14,7 +14,7 @@
  * };
  *
  * // In your code:
- * Cerr << "TMyClass instances in use: " << TMyClass::ObjectCount() << Endl;
+ * std::cerr << "TMyClass instances in use: " << TMyClass::ObjectCount() << std::endl;
  * \endcode
  */
 template <class T>
diff --git a/util/generic/overloaded.h b/util/generic/overloaded.h
index 3653eb29464..562392decf1 100644
--- a/util/generic/overloaded.h
+++ b/util/generic/overloaded.h
@@ -7,9 +7,9 @@
  * ```
  * std::variant<int, void*, std::string> var;
  * Visit(TOverloaded{
- *     [](int val) { Cerr << "int: " << val; },
- *     [](void* val) { Cerr << "ptr: " << val; },
- *     [](const std::string& val) { Cerr << "str: " << val; },
+ *     [](int val) { std::cerr << "int: " << val; },
+ *     [](void* val) { std::cerr << "ptr: " << val; },
+ *     [](const std::string& val) { std::cerr << "str: " << val; },
  * }, var);
  * ```
  *
@@ -24,7 +24,7 @@
  * ```
  * std::variant<int, double, char> var;
  * Visit(TOverloaded{
- *     [](double val) { Cerr << "dbl: " << val; },
+ *     [](double val) { std::cerr << "dbl: " << val; },
  * }, var);
  * ```
  *
@@ -35,11 +35,11 @@
  * Visit([](auto&& val) {
  *     using T = std::decay_t<decltype(val)>;
  *     if constexpr (std::is_same_v<T, int>) {
- *         Cerr << "int: " << val;
+ *         std::cerr << "int: " << val;
  *     } else if constexpr (std::is_same_v<T, double>) {
- *         Cerr << "dbl: " << val;
+ *         std::cerr << "dbl: " << val;
  *     } else if constexpr (std::is_same_v<T, char>) {
- *         Cerr << "chr: " << val;
+ *         std::cerr << "chr: " << val;
  *     } else {
  *         static_assert(TDependentFalse<T>, "unexpected type");
  *     }
diff --git a/util/generic/va_args.h b/util/generic/va_args.h
index 33498d47ed3..2265941c1d1 100644
--- a/util/generic/va_args.h
+++ b/util/generic/va_args.h
@@ -772,8 +772,8 @@
  * Example usage:
  *
  * @code{cpp}
- * #define I1(arg1) Cout << Y_STRINGIZE(arg1) << Endl;
- * #define I2(arg1, arg2) Cout << Y_STRINGIZE(arg1) << ';' << Y_STRINGIZE(arg2) << Endl;
+ * #define I1(arg1) std::cout << Y_STRINGIZE(arg1) << std::endl;
+ * #define I2(arg1, arg2) std::cout << Y_STRINGIZE(arg1) << ';' << Y_STRINGIZE(arg2) << std::endl;
  *
  * #define Y_PRINT(...) Y_PASS_VA_ARGS(Y_MACRO_IMPL_DISPATCHER_2(__VA_ARGS__, I2, I1)(__VA_ARGS__))
  * @endcode
diff --git a/util/generic/ymath_ut.cpp b/util/generic/ymath_ut.cpp
index 29190b55eb4..649e802eae4 100644
--- a/util/generic/ymath_ut.cpp
+++ b/util/generic/ymath_ut.cpp
@@ -108,7 +108,7 @@ void TMathTest::TestClp2() {
                 ret += FastClp2(i);
             }
 
-            Cerr << ret << Endl;
+            std::cerr << ret << std::endl;
         }
 
         {
@@ -119,7 +119,7 @@ void TMathTest::TestClp2() {
                 ret += SlowClp2(i);
             }
 
-            Cerr << ret << Endl;
+            std::cerr << ret << std::endl;
         }
     }
 }
diff --git a/util/stream/ios_ut.cpp b/util/stream/ios_ut.cpp
index 640dc807fc9..a249c30ea15 100644
--- a/util/stream/ios_ut.cpp
+++ b/util/stream/ios_ut.cpp
@@ -373,7 +373,7 @@ namespace {
         while (input.ReadLine(line)) {
             ++i;
         }
-        Cout << comment << ":" << (Now() - start).SecondsFloat() << Endl;
+        std::cout << comment << ":" << (Now() - start).SecondsFloat() << std::endl;
         UNIT_ASSERT_VALUES_EQUAL(i, 100000);
     }
 
diff --git a/util/stream/output.h b/util/stream/output.h
index 9163360e233..c6dde4426d4 100644
--- a/util/stream/output.h
+++ b/util/stream/output.h
@@ -273,10 +273,6 @@ namespace NPrivate {
  */
 #define Cerr (::NPrivate::StdErrStream())
 
-/**
- * Standard log stream.
- */
-#define Clog Cerr
 
 /**
  * End-of-line output manipulator, basically the same as `std::endl`.
diff --git a/util/string/split.h b/util/string/split.h
index 3e272d428d0..3ad6bb8457b 100644
--- a/util/string/split.h
+++ b/util/string/split.h
@@ -465,7 +465,7 @@ void Split(std::string_view s, D delim, P1& p1, P2& p2, Other&... other) {
  * std::vector<std::string_view> values = StringSplitter("1\t2\t3").Split('\t');
  *
  * for(std::string_view part: StringSplitter("1::2::::3").SplitByString("::").SkipEmpty()) {
- *     Cerr << part;
+ *     std::cerr << part;
  * }
  *
  * std::vector<std::string> firstTwoValues = StringSplitter("1\t2\t3").Split('\t').Take(2);
diff --git a/util/string/split_ut.cpp b/util/string/split_ut.cpp
index 05cf1d3160b..aee860d1c5d 100644
--- a/util/string/split_ut.cpp
+++ b/util/string/split_ut.cpp
@@ -6,6 +6,7 @@
 #include <util/charset/wide.h>
 #include <util/datetime/cputimer.h>
 
+#include <iostream>
 #include <string>
 #include <string_view>
 
@@ -27,7 +28,7 @@ inline void Cmp(const T1& t1, const T2& t2) {
         UNIT_ASSERT_EQUAL(t1.size(), t2.size());
     } catch (...) {
         Print(t1);
-        Cerr << "---------------" << Endl;
+        std::cerr << "---------------" << std::endl;
         Print(t2);
 
         throw;
@@ -40,7 +41,7 @@ inline void Cmp(const T1& t1, const T2& t2) {
         try {
             UNIT_ASSERT_EQUAL(*i, *j);
         } catch (...) {
-            Cerr << "(" << *i << ")->(" << *j << ")" << Endl;
+            std::cerr << "(" << *i << ")->(" << *j << ")" << std::endl;
 
             throw;
         }
@@ -50,7 +51,7 @@ inline void Cmp(const T1& t1, const T2& t2) {
 template <class T>
 inline void Print(const T& t) {
     for (typename T::const_iterator i = t.begin(); i != t.end(); ++i) {
-        Cerr << *i << Endl;
+        std::cerr << *i << std::endl;
     }
 }
 
diff --git a/util/system/compiler.h b/util/system/compiler.h
index 1051aac591b..c29cb3b2c93 100644
--- a/util/system/compiler.h
+++ b/util/system/compiler.h
@@ -25,12 +25,12 @@
  *
  * @code
  * void Hi() {
- *     Cout << Y_FUNC_SIGNATURE << Endl;
+ *     std::cout << Y_FUNC_SIGNATURE << std::endl;
  * }
 
  * template <typename T>
  * void Do() {
- *     Cout << Y_FUNC_SIGNATURE << Endl;
+ *     std::cout << Y_FUNC_SIGNATURE << std::endl;
  * }
 
  * int main() {
diff --git a/util/system/context.cpp b/util/system/context.cpp
index cd03d0e1dcf..442885348fa 100644
--- a/util/system/context.cpp
+++ b/util/system/context.cpp
@@ -3,6 +3,8 @@
 #include "event.h"
 #include "thread.h"
 
+#include <iostream>
+
 #include <cstdlib> //for abort()
 
 #if defined(_win_)
@@ -37,7 +39,7 @@ void ITrampoLine::DoRunNaked() {
     try {
         DoRun();
     } catch (...) {
-        Cerr << "Uncaught exception in coroutine: " << CurrentExceptionMessage() << "\n";
+        std::cerr << "Uncaught exception in coroutine: " << CurrentExceptionMessage() << "\n";
     }
 
     abort();
diff --git a/util/system/cpu_id_ut.cpp b/util/system/cpu_id_ut.cpp
index 68f1f8aac7f..9e0143b474a 100644
--- a/util/system/cpu_id_ut.cpp
+++ b/util/system/cpu_id_ut.cpp
@@ -78,7 +78,7 @@ Y_UNIT_TEST_SUITE(TestCpuId) {
     Y_UNIT_TEST(TestCpuBrand) {
         ui32 store[12];
 
-        //Cout << CpuBrand(store) << Endl;;
+        //std::cout << CpuBrand(store) << std::endl;
 
         UNIT_ASSERT(strlen(CpuBrand(store)) > 0);
     }
diff --git a/util/system/execpath_ut.cpp b/util/system/execpath_ut.cpp
index bf97fd4d490..88b1983cbdf 100644
--- a/util/system/execpath_ut.cpp
+++ b/util/system/execpath_ut.cpp
@@ -4,6 +4,8 @@
 
 #include <util/folder/dirut.h>
 
+#include <iostream>
+
 Y_UNIT_TEST_SUITE(TExecPathTest) {
     Y_UNIT_TEST(TestIt) {
         std::string execPath = GetExecPath();
@@ -13,7 +15,7 @@ Y_UNIT_TEST_SUITE(TExecPathTest) {
             UNIT_ASSERT(NFs::Exists(execPath));
             UNIT_ASSERT(NFs::Exists(persistentExecPath));
         } catch (...) {
-            Cerr << execPath << Endl;
+            std::cerr << execPath << std::endl;
 
             throw;
         }
diff --git a/util/system/file.cpp b/util/system/file.cpp
index 66fec31a089..b3e96cba2b2 100644
--- a/util/system/file.cpp
+++ b/util/system/file.cpp
@@ -1352,7 +1352,7 @@ TFile Duplicate(int fd) {
 
     FHANDLE dupHandle;
     if (!::DuplicateHandle(GetCurrentProcess(), handle, GetCurrentProcess(), &dupHandle, 0, TRUE, DUPLICATE_SAME_ACCESS)) {
-        ythrow TFileError() << "can not duplicate file descriptor " << LastSystemError() << Endl;
+        ythrow TFileError() << "can not duplicate file descriptor " << LastSystemError() << std::endl;
     }
 
     return TFile(dupHandle);
diff --git a/util/system/fstat_ut.cpp b/util/system/fstat_ut.cpp
index a6cb9544bbc..b110a1259d0 100644
--- a/util/system/fstat_ut.cpp
+++ b/util/system/fstat_ut.cpp
@@ -66,19 +66,19 @@ Y_UNIT_TEST_SUITE(TestFileStat) {
     // Symlinks require additional privileges on windows.
     // Skip test if we are not allowed to create one.
     // Wine returns true from NFs::SymLink, but actually does nothing
-    #define SAFE_SYMLINK(target, link)                                                \
-        do {                                                                          \
-            auto res = NFs::SymLink(target, link);                                    \
-            if (!res) {                                                               \
-                auto err = LastSystemError();                                         \
-                Cerr << "can't create symlink: " << LastSystemErrorText(err) << Endl; \
-                UNIT_ASSERT(err == ERROR_PRIVILEGE_NOT_HELD);                         \
-                return;                                                               \
-            }                                                                         \
-            if (!NFs::Exists(link) && IsWine()) {                                     \
-                Cerr << "wine does not support symlinks" << Endl;                     \
-                return;                                                               \
-            }                                                                         \
+    #define SAFE_SYMLINK(target, link)                                                          \
+        do {                                                                                    \
+            auto res = NFs::SymLink(target, link);                                              \
+            if (!res) {                                                                         \
+                auto err = LastSystemError();                                                   \
+                std::cerr << "can't create symlink: " << LastSystemErrorText(err) << std::endl; \
+                UNIT_ASSERT(err == ERROR_PRIVILEGE_NOT_HELD);                                   \
+                return;                                                                         \
+            }                                                                                   \
+            if (!NFs::Exists(link) && IsWine()) {                                               \
+                std::cerr << "wine does not support symlinks" << std::endl;                     \
+                return;                                                                         \
+            }                                                                                   \
         } while (false)
 
     bool IsWine() {
diff --git a/util/system/hostname_ut.cpp b/util/system/hostname_ut.cpp
index 7e0da106b6e..507e54abcbe 100644
--- a/util/system/hostname_ut.cpp
+++ b/util/system/hostname_ut.cpp
@@ -2,6 +2,8 @@
 
 #include <library/cpp/testing/unittest/registar.h>
 
+#include <iostream>
+
 Y_UNIT_TEST_SUITE(THostNameTest) {
     Y_UNIT_TEST(Test1) {
         UNIT_ASSERT(*GetHostName() != '?');
@@ -17,7 +19,7 @@ Y_UNIT_TEST_SUITE(THostNameTest) {
         try {
             UNIT_ASSERT(IsFQDN(x));
         } catch (...) {
-            Cerr << x << Endl;
+            std::cerr << x << std::endl;
 
             throw;
         }
diff --git a/util/system/progname_ut.cpp b/util/system/progname_ut.cpp
index 12892a8723b..33e2b8f53ae 100644
--- a/util/system/progname_ut.cpp
+++ b/util/system/progname_ut.cpp
@@ -2,6 +2,8 @@
 
 #include <library/cpp/testing/unittest/registar.h>
 
+#include <iostream>
+
 Y_UNIT_TEST_SUITE(TProgramNameTest) {
     Y_UNIT_TEST(TestIt) {
         std::string progName = GetProgramName();
@@ -10,7 +12,7 @@ Y_UNIT_TEST_SUITE(TProgramNameTest) {
             UNIT_ASSERT(
                 progName.find("ut_util") != std::string::npos || progName.find("util-system_ut") != std::string::npos || progName.find("util-system-ut") != std::string::npos);
         } catch (...) {
-            Cerr << progName << Endl;
+            std::cerr << progName << std::endl;
 
             throw;
         }
diff --git a/util/system/shellcommand.cpp b/util/system/shellcommand.cpp
index ee2101c0f63..e93030fc7bc 100644
--- a/util/system/shellcommand.cpp
+++ b/util/system/shellcommand.cpp
@@ -17,6 +17,7 @@
 #include <util/system/info.h>
 
 #include <errno.h>
+#include <iostream>
 #include <mutex>
 
 #if defined(_unix_)
@@ -592,7 +593,7 @@ void TShellCommand::TImpl::StartProcess(TShellCommand::TImpl::TPipes& pipes) {
     }
     Pid = process_info.hProcess;
     CloseHandle(process_info.hThread);
-    DBG(Cerr << "created process id " << Pid << " in dir: " << cwd << ", cmd: " << cmdcopy.Data() << Endl);
+    DBG(std::cerr << "created process id " << Pid << " in dir: " << cwd << ", cmd: " << cmdcopy.Data() << std::endl);
 }
 #endif
 
@@ -712,12 +713,12 @@ void TShellCommand::TImpl::OnFork(TPipes& pipes, sigset_t oldmask, char* const*
         } else {
             execve(argv[0], argv, envp);
         }
-        Cerr << "Process was not created: " << LastSystemErrorText() << Endl;
+        std::cerr << "Process was not created: " << LastSystemErrorText() << std::endl;
     } catch (const std::exception& error) {
-        Cerr << "Process was not created: " << error.what() << Endl;
+        std::cerr << "Process was not created: " << error.what() << std::endl;
     } catch (...) {
-        Cerr << "Process was not created: "
-             << "unknown error" << Endl;
+        std::cerr << "Process was not created: "
+             << "unknown error" << std::endl;
     }
 
     _exit(-1);
@@ -912,7 +913,7 @@ void TShellCommand::TImpl::Communicate(TProcessInfo* pi) {
                     WaitForSingleObject(pi->Parent->Pid /* process_info.hProcess */, pi->Parent->Options_.PollDelayMs /* ms */);
                 Y_UNUSED(status);
 #endif
-                // DBG(Cerr << "wait result: " << waitPidResult << Endl);
+                // DBG(std::cerr << "wait result: " << waitPidResult << std::endl);
                 if (waitPidResult != WAIT_PROCEED) {
                     break;
                 }
@@ -924,15 +925,15 @@ void TShellCommand::TImpl::Communicate(TProcessInfo* pi) {
             bool haveErr = false;
 
             if (!input && pi->InputFd.IsOpen()) {
-                DBG(Cerr << "closing input stream..." << Endl);
+                DBG(std::cerr << "closing input stream..." << std::endl);
                 pi->InputFd.Close();
             }
             if (!output && pi->OutputFd.IsOpen()) {
-                DBG(Cerr << "closing output stream..." << Endl);
+                DBG(std::cerr << "closing output stream..." << std::endl);
                 pi->OutputFd.Close();
             }
             if (!error && pi->ErrorFd.IsOpen()) {
-                DBG(Cerr << "closing error stream..." << Endl);
+                DBG(std::cerr << "closing error stream..." << std::endl);
                 pi->ErrorFd.Close();
             }
 
@@ -957,9 +958,9 @@ void TShellCommand::TImpl::Communicate(TProcessInfo* pi) {
             }
 
             res = PollD(fds, 3, TInstant::Now() + TDuration::MilliSeconds(pi->Parent->Options_.PollDelayMs));
-            // DBG(Cerr << "poll result: " << res << Endl);
+            // DBG(std::cerr << "poll result: " << res << std::endl);
             if (-res == ETIMEDOUT || res == 0) {
-                // DBG(Cerr << "poll again..." << Endl);
+                // DBG(std::cerr << "poll again..." << std::endl);
                 continue;
             }
             if (res < 0) {
@@ -984,7 +985,7 @@ void TShellCommand::TImpl::Communicate(TProcessInfo* pi) {
 
             if (haveOut) {
                 bytes = pi->OutputFd.Read(buffer.Data(), buffer.Capacity());
-                DBG(Cerr << "transferred " << bytes << " bytes of output" << Endl);
+                DBG(std::cerr << "transferred " << bytes << " bytes of output" << std::endl);
                 if (bytes > 0) {
                     output->Write(buffer.Data(), bytes);
                 } else {
@@ -993,7 +994,7 @@ void TShellCommand::TImpl::Communicate(TProcessInfo* pi) {
             }
             if (haveErr) {
                 bytes = pi->ErrorFd.Read(buffer.Data(), buffer.Capacity());
-                DBG(Cerr << "transferred " << bytes << " bytes of error" << Endl);
+                DBG(std::cerr << "transferred " << bytes << " bytes of error" << std::endl);
                 if (bytes > 0) {
                     error->Write(buffer.Data(), bytes);
                 } else {
@@ -1021,11 +1022,11 @@ void TShellCommand::TImpl::Communicate(TProcessInfo* pi) {
                     input = nullptr;
                 }
 
-                DBG(Cerr << "transferred " << bytes << " bytes of input" << Endl);
+                DBG(std::cerr << "transferred " << bytes << " bytes of input" << );
             }
 #endif
         }
-        DBG(Cerr << "process finished" << Endl);
+        DBG(std::cerr << "process finished" << std::endl);
 
         // What's the reason of process exit.
         // We need to set exit code before waiting for input thread
@@ -1049,7 +1050,7 @@ void TShellCommand::TImpl::Communicate(TProcessInfo* pi) {
             if (exitCode == 0)
                 cleanExit = true;
             processExitCode = static_cast<int>(exitCode);
-            DBG(Cerr << "exit code: " << exitCode << Endl);
+            DBG(std::cerr << "exit code: " << exitCode << std::endl);
         }
 #endif
         pi->Parent->ExitCode = processExitCode;
@@ -1069,11 +1070,11 @@ void TShellCommand::TImpl::Communicate(TProcessInfo* pi) {
 #else
         // Now let's read remaining stdout/stderr
         while (output && (bytes = pi->OutputFd.Read(buffer.Data(), buffer.Capacity())) > 0) {
-            DBG(Cerr << bytes << " more bytes of output: " << Endl);
+            DBG(std::cerr << bytes << " more bytes of output: " << std::endl);
             output->Write(buffer.Data(), bytes);
         }
         while (error && (bytes = pi->ErrorFd.Read(buffer.Data(), buffer.Capacity())) > 0) {
-            DBG(Cerr << bytes << " more bytes of error" << Endl);
+            DBG(std::cerr << bytes << " more bytes of error" << std::endl);
             error->Write(buffer.Data(), bytes);
         }
 #endif
diff --git a/util/system/yassert.cpp b/util/system/yassert.cpp
index 78e610498f3..6b4b39b51df 100644
--- a/util/system/yassert.cpp
+++ b/util/system/yassert.cpp
@@ -14,6 +14,8 @@
 #include <stdarg.h>
 #include <stdio.h>
 
+#include <iostream>
+
 #ifdef CLANG_COVERAGE
 extern "C" {
     // __llvm_profile_write_file may not be provided if the executable target uses NO_CLANG_COVERAGE() macro and
@@ -80,13 +82,13 @@ namespace NPrivate {
         } else {
             o << "  " << function << "() failed" << Endl;
         }
-        Cerr << r << Flush;
+        std::cerr << r << std::flush;
 #ifndef WITH_VALGRIND
         PrintBackTrace();
 #endif
 #ifdef CLANG_COVERAGE
         if (__llvm_profile_write_file()) {
-            Cerr << "Failed to dump clang coverage" << Endl;
+            std::cerr << "Failed to dump clang coverage" << std::endl;
         }
 #endif
         abort();
diff --git a/ydb/library/grpc/client/grpc_client_low.cpp b/ydb/library/grpc/client/grpc_client_low.cpp
index ad1baf22b07..74444216f4c 100644
--- a/ydb/library/grpc/client/grpc_client_low.cpp
+++ b/ydb/library/grpc/client/grpc_client_low.cpp
@@ -49,20 +49,20 @@ void EnableGRpcTracing() {
 //     }
 //     bool SetOption(int fd) {
 //         if (!SetOption(fd, SOL_SOCKET, SO_KEEPALIVE, 1)) {
-//             Cerr << std::format("Failed to set SO_KEEPALIVE option: {}", strerror(errno)) << Endl;
+//             std::cerr << std::format("Failed to set SO_KEEPALIVE option: {}", strerror(errno)) << std::endl;
 //             return false;
 //         }
 // #ifdef _linux_
 //         if (Idle_ && !SetOption(fd, IPPROTO_TCP, TCP_KEEPIDLE, Idle_)) {
-//             Cerr << std::format("Failed to set TCP_KEEPIDLE option: {}", strerror(errno)) << Endl;
+//             std::cerr << std::format("Failed to set TCP_KEEPIDLE option: {}", strerror(errno)) << std::endl;
 //             return false;
 //         }
 //         if (Count_ && !SetOption(fd, IPPROTO_TCP, TCP_KEEPCNT, Count_)) {
-//             Cerr << std::format("Failed to set TCP_KEEPCNT option: {}", strerror(errno)) << Endl;
+//             std::cerr << std::format("Failed to set TCP_KEEPCNT option: {}", strerror(errno)) << std::endl;
 //             return false;
 //         }
 //         if (Interval_ && !SetOption(fd, IPPROTO_TCP, TCP_KEEPINTVL, Interval_)) {
-//             Cerr << std::format("Failed to set TCP_KEEPINTVL option: {}", strerror(errno)) << Endl;
+//             std::cerr << std::format("Failed to set TCP_KEEPINTVL option: {}", strerror(errno)) << std::endl;
 //             return false;
 //         }
 // #endif
diff --git a/ydb/public/lib/operation_id/operation_id_ut.cpp b/ydb/public/lib/operation_id/operation_id_ut.cpp
index fb9546089d7..36782f2d05c 100644
--- a/ydb/public/lib/operation_id/operation_id_ut.cpp
+++ b/ydb/public/lib/operation_id/operation_id_ut.cpp
@@ -60,7 +60,7 @@ Y_UNIT_TEST_SUITE(OperationIdTest) {
             auto result = FormatPreparedQueryIdCompat(PreparedQueryId);
             x += result.size();
         }
-        Cerr << x << Endl;
+        std::cerr << x << std::endl;
     }
 
     Y_UNIT_TEST(PreparedQueryIdDecodePerf) {
@@ -73,7 +73,7 @@ Y_UNIT_TEST_SUITE(OperationIdTest) {
             UNIT_ASSERT_VALUES_EQUAL(PreparedQueryId, decodedString);
             x += decodedString.size();
         }
-        Cerr << x << Endl;
+        std::cerr << x << std::endl;
     }
 
     Y_UNIT_TEST(PreparedQueryIdOldFormatterPerf) {
@@ -85,7 +85,7 @@ Y_UNIT_TEST_SUITE(OperationIdTest) {
             auto result = ProtoToString(opId);
             x += result.size();
         }
-        Cerr << x << Endl;
+        std::cerr << x << std::endl;
     }
 #endif
     Y_UNIT_TEST(ConvertKindAndValues) {