diff --git a/td/generate/scheme/td_api.tl b/td/generate/scheme/td_api.tl
index a95ad005..2274f5ab 100644
--- a/td/generate/scheme/td_api.tl
+++ b/td/generate/scheme/td_api.tl
@@ -3402,3 +3402,7 @@ testGetDifference = Ok;
 testUseUpdate = Update;
 //@description Does nothing and ensures that the Error object is used; for testing only
 testUseError = Error;
+//@description Changes verbosity level for a specified log tag; for testing only. This is an offline method. Can be called before authorization. Can be called synchronously
+//@tag Logging tag to change verbosity level (one of "td_init", "update_file", "connections", "binlog", "proxy", "net_query", "td_requests", "dc", "files", "mtproto", "raw_mtproto", "fd", "actor", "buffer", "sqlite")
+//@new_verbosity_level New verbosity level; 0-1023
+testSetLogTagVerbosityLevel tag:string new_verbosity_level:int32 = Ok;
diff --git a/td/generate/scheme/td_api.tlo b/td/generate/scheme/td_api.tlo
index 2003be21..1604efac 100644
Binary files a/td/generate/scheme/td_api.tlo and b/td/generate/scheme/td_api.tlo differ
diff --git a/td/telegram/Td.cpp b/td/telegram/Td.cpp
index 0a34cce2..ed89bfc4 100644
--- a/td/telegram/Td.cpp
+++ b/td/telegram/Td.cpp
@@ -73,6 +73,8 @@
 
 #include "td/mtproto/utils.h"  // for create_storer, fetch_result, etc, TODO
 
+#include "tdnet/td/net/TransparentProxy.h"
+
 #include "td/utils/buffer.h"
 #include "td/utils/filesystem.h"
 #include "td/utils/format.h"
@@ -3251,6 +3253,7 @@ bool Td::is_synchronous_request(int32 id) {
     case td_api::getFileExtension::ID:
     case td_api::cleanFileName::ID:
     case td_api::getLanguagePackString::ID:
+    case td_api::testSetLogTagVerbosityLevel::ID:
       return true;
     default:
       return false;
@@ -6907,6 +6910,73 @@ void Td::on_request(uint64 id, td_api::testGetDifference &request) {
   send_closure(actor_id(this), &Td::send_result, id, make_tl_object<td_api::ok>());
 }
 
+static int *get_log_verbosity_level(Slice name) {
+  if (name == "td_init") {
+    return &VERBOSITY_NAME(td_init);
+  }
+  if (name == "update_file") {
+    return &VERBOSITY_NAME(update_file);
+  }
+  if (name == "connections") {
+    return &VERBOSITY_NAME(connections);
+  }
+  if (name == "binlog") {
+    return &VERBOSITY_NAME(binlog);
+  }
+  if (name == "proxy") {
+    return &VERBOSITY_NAME(proxy);
+  }
+  if (name == "net_query") {
+    return &VERBOSITY_NAME(net_query);
+  }
+  if (name == "td_requests") {
+    return &VERBOSITY_NAME(td_requests);
+  }
+  if (name == "dc") {
+    return &VERBOSITY_NAME(dc);
+  }
+  if (name == "files") {
+    return &VERBOSITY_NAME(files);
+  }
+  if (name == "mtproto") {
+    return &VERBOSITY_NAME(mtproto);
+  }
+  if (name == "raw_mtproto") {
+    return &VERBOSITY_NAME(raw_mtproto);
+  }
+  if (name == "fd") {
+    return &VERBOSITY_NAME(fd);
+  }
+  if (name == "actor") {
+    return &VERBOSITY_NAME(actor);
+  }
+  if (name == "buffer") {
+    return &VERBOSITY_NAME(buffer);
+  }
+  if (name == "sqlite") {
+    return &VERBOSITY_NAME(sqlite);
+  }
+  return nullptr;
+}
+
+void Td::on_request(uint64 id, td_api::testSetLogTagVerbosityLevel &request) {
+  UNREACHABLE();
+}
+
+td_api::object_ptr<td_api::Object> Td::do_static_request(const td_api::testSetLogTagVerbosityLevel &request) {
+  if (request.new_verbosity_level_ < 0 || request.new_verbosity_level_ > 1023) {
+    return td_api::make_object<td_api::error>(400, "Wrong new verbosity level");
+  }
+
+  int *level = get_log_verbosity_level(request.tag_);
+  if (level == nullptr) {
+    return td_api::make_object<td_api::error>(400, "Log tag is not found");
+  }
+  *level = static_cast<int>(request.new_verbosity_level_);
+
+  return td_api::make_object<td_api::ok>();
+}
+
 void Td::on_request(uint64 id, td_api::testUseUpdate &request) {
   send_closure(actor_id(this), &Td::send_result, id, nullptr);
 }
diff --git a/td/telegram/Td.h b/td/telegram/Td.h
index cad3a1b6..0d66fd7b 100644
--- a/td/telegram/Td.h
+++ b/td/telegram/Td.h
@@ -906,6 +906,7 @@ class Td final : public NetQueryCallback {
   // test
   void on_request(uint64 id, td_api::testNetwork &request);
   void on_request(uint64 id, td_api::testGetDifference &request);
+  void on_request(uint64 id, td_api::testSetLogTagVerbosityLevel &request);
   void on_request(uint64 id, td_api::testUseUpdate &request);
   void on_request(uint64 id, td_api::testUseError &request);
   void on_request(uint64 id, td_api::testCallEmpty &request);
@@ -925,6 +926,7 @@ class Td final : public NetQueryCallback {
   static td_api::object_ptr<td_api::Object> do_static_request(const td_api::getFileExtension &request);
   static td_api::object_ptr<td_api::Object> do_static_request(const td_api::cleanFileName &request);
   static td_api::object_ptr<td_api::Object> do_static_request(const td_api::getLanguagePackString &request);
+  static td_api::object_ptr<td_api::Object> do_static_request(const td_api::testSetLogTagVerbosityLevel &request);
 
   Status init(DbKey key) TD_WARN_UNUSED_RESULT;
   void clear();
diff --git a/td/telegram/cli.cpp b/td/telegram/cli.cpp
index 17a11b4a..74a1a221 100644
--- a/td/telegram/cli.cpp
+++ b/td/telegram/cli.cpp
@@ -3381,6 +3381,16 @@ class CliClient final : public Actor {
       td::Log::set_verbosity_level(static_cast<int>(op.size()));
     } else if (op[0] == 'v' && ('0' <= op[1] && op[1] <= '9')) {
       td::Log::set_verbosity_level(to_integer<int>(op.substr(1)));
+    } else if (op == "sltvl" || op == "sltvle") {
+      string tag;
+      string level;
+      std::tie(tag, level) = split(args);
+      auto request = make_tl_object<td_api::testSetLogTagVerbosityLevel>(tag, to_integer<int32>(level));
+      if (op == "sltvl") {
+        send_request(std::move(request));
+      } else {
+        execute(std::move(request));
+      }
     } else if (op == "q" || op == "Quit") {
       quit();
     } else if (op == "dnq" || op == "DumpNetQueries") {
diff --git a/td/telegram/files/FileManager.cpp b/td/telegram/files/FileManager.cpp
index 03f5f7b6..2d88c29a 100644
--- a/td/telegram/files/FileManager.cpp
+++ b/td/telegram/files/FileManager.cpp
@@ -35,7 +35,7 @@
 
 namespace td {
 
-static int VERBOSITY_NAME(update_file) = VERBOSITY_NAME(DEBUG);
+int VERBOSITY_NAME(update_file) = VERBOSITY_NAME(DEBUG);
 
 FileNode *FileNodePtr::operator->() const {
   return get();
diff --git a/td/telegram/files/FileManager.h b/td/telegram/files/FileManager.h
index e36ac765..1bc4eb6d 100644
--- a/td/telegram/files/FileManager.h
+++ b/td/telegram/files/FileManager.h
@@ -35,6 +35,8 @@
 
 namespace td {
 
+extern int VERBOSITY_NAME(update_file);
+
 enum class FileLocationSource : int8 { None, FromUser, FromDb, FromServer };
 
 class FileNode {
diff --git a/td/telegram/net/ConnectionCreator.cpp b/td/telegram/net/ConnectionCreator.cpp
index 493876e4..faf319df 100644
--- a/td/telegram/net/ConnectionCreator.cpp
+++ b/td/telegram/net/ConnectionCreator.cpp
@@ -41,7 +41,7 @@
 
 namespace td {
 
-static int VERBOSITY_NAME(connections) = VERBOSITY_NAME(DEBUG) + 8;
+int VERBOSITY_NAME(connections) = VERBOSITY_NAME(DEBUG) + 8;
 
 namespace detail {
 
diff --git a/td/telegram/net/ConnectionCreator.h b/td/telegram/net/ConnectionCreator.h
index 65073ca5..ccc8ea59 100644
--- a/td/telegram/net/ConnectionCreator.h
+++ b/td/telegram/net/ConnectionCreator.h
@@ -48,6 +48,8 @@ class GetHostByNameActor;
 
 namespace td {
 
+extern int VERBOSITY_NAME(connections);
+
 class Proxy {
  public:
   static Proxy socks5(string server, int32 port, string user, string password) {
diff --git a/tdutils/td/utils/OptionsParser.h b/tdutils/td/utils/OptionsParser.h
index 6ac03855..c59c654a 100644
--- a/tdutils/td/utils/OptionsParser.h
+++ b/tdutils/td/utils/OptionsParser.h
@@ -57,7 +57,6 @@ class OptionsParser {
 #if TD_WINDOWS
     return -1;
 #else
-    // use getopt. long keys are not supported for now
     char buff[1024];
     StringBuilder sb({buff, sizeof(buff)});
     for (auto &opt : options_) {