diff --git a/fineftp-server/src/filesystem.cpp b/fineftp-server/src/filesystem.cpp
index 6de5182..e0a51c8 100644
--- a/fineftp-server/src/filesystem.cpp
+++ b/fineftp-server/src/filesystem.cpp
@@ -297,7 +297,7 @@ namespace Filesystem
     hFind = FindFirstFileW(w_find_file_path.c_str(), &ffd);
     if (hFind == INVALID_HANDLE_VALUE)
     {
-      std::cerr << "FindFirstFile Error" << std::endl;
+      error_ << "FindFirstFile Error" << std::endl;
       return content;
     }
 
@@ -312,7 +312,7 @@ namespace Filesystem
     struct dirent *dirp = nullptr;
     if(dp == nullptr)
     {
-        std::cerr << "Error opening directory: " << strerror(errno) << std::endl;
+        error << "Error opening directory: " << strerror(errno) << std::endl;
         return content;
     }
 
diff --git a/fineftp-server/src/ftp_session.cpp b/fineftp-server/src/ftp_session.cpp
index 168133d..42f803b 100755
--- a/fineftp-server/src/ftp_session.cpp
+++ b/fineftp-server/src/ftp_session.cpp
@@ -57,7 +57,7 @@ namespace fineftp
   FtpSession::~FtpSession()
   {
 #ifndef NDEBUG
-    std::cout << "Ftp Session shutting down" << std::endl;
+    output_ << "Ftp Session shutting down" << std::endl;
 #endif // !NDEBUG
 
     {
@@ -87,7 +87,7 @@ namespace fineftp
   {
     asio::error_code ec;
     command_socket_.set_option(asio::ip::tcp::no_delay(true), ec);
-    if (ec) std::cerr << "Unable to set socket option tcp::no_delay: " << ec.message() << std::endl;
+    if (ec) error_ << "Unable to set socket option tcp::no_delay: " << ec.message() << std::endl;
 
     command_strand_.post([me = shared_from_this()]() { me->readFtpCommand(); });
     sendFtpMessage(FtpMessage(FtpReplyCode::SERVICE_READY_FOR_NEW_USER, "Welcome to fineFTP Server"));
@@ -123,7 +123,7 @@ namespace fineftp
   void FtpSession::startSendingMessages()
   {
 #ifndef NDEBUG
-    std::cout << "FTP >> " << command_output_queue_.front() << std::endl;
+    output_ << "FTP >> " << command_output_queue_.front() << std::endl;
 #endif
 
     asio::async_write(command_socket_
@@ -152,7 +152,7 @@ namespace fineftp
                         }
                         else
                         {
-                          std::cerr << "Command write error for message " << me->command_output_queue_.front() << ec.message() << std::endl;
+                          me->error_ << "Command write error for message " << me->command_output_queue_.front() << ec.message() << std::endl;
                         }
                       }
                     ));
@@ -167,12 +167,12 @@ namespace fineftp
                           {
                             if (ec != asio::error::eof)
                             {
-                              std::cerr << "read_until error: " << ec.message() << std::endl;
+                              me->error_ << "read_until error: " << ec.message() << std::endl;
                             }
 #ifndef NDEBUG
                             else
                             {
-                              std::cout << "Control connection closed by client." << std::endl;
+                              me->output_ << "Control connection closed by client." << std::endl;
                             }
 #endif // !NDEBUG
                             // Close the data connection, if it is open
@@ -200,7 +200,7 @@ namespace fineftp
 
                           stream.ignore(2); // Remove the "\r\n"
 #ifndef NDEBUG
-                          std::cout << "FTP << " << packet_string << std::endl;
+                          me->output_ << "FTP << " << packet_string << std::endl;
 #endif
 
                           me->handleFtpCommand(packet_string);
@@ -414,7 +414,7 @@ namespace fineftp
       data_acceptor_.close(ec);
       if (ec)
       {
-        std::cerr << "Error closing data acceptor: " << ec.message() << std::endl;
+        error_ << "Error closing data acceptor: " << ec.message() << std::endl;
       }
     }
 
@@ -425,7 +425,7 @@ namespace fineftp
       data_acceptor_.open(endpoint.protocol(), ec);
       if (ec)
       {
-        std::cerr << "Error opening data acceptor: " << ec.message() << std::endl;
+        error_ << "Error opening data acceptor: " << ec.message() << std::endl;
         sendFtpMessage(FtpReplyCode::SERVICE_NOT_AVAILABLE, "Failed to enter passive mode.");
         return;
       }
@@ -435,7 +435,7 @@ namespace fineftp
       data_acceptor_.bind(endpoint, ec);
       if (ec)
       {
-        std::cerr << "Error binding data acceptor: " << ec.message() << std::endl;
+        error_ << "Error binding data acceptor: " << ec.message() << std::endl;
         sendFtpMessage(FtpReplyCode::SERVICE_NOT_AVAILABLE, "Failed to enter passive mode.");
         return;
       }
@@ -445,7 +445,7 @@ namespace fineftp
       data_acceptor_.listen(asio::socket_base::max_connections, ec);
       if (ec)
       {
-        std::cerr << "Error listening on data acceptor: " << ec.message() << std::endl;
+        error_ << "Error listening on data acceptor: " << ec.message() << std::endl;
         sendFtpMessage(FtpReplyCode::SERVICE_NOT_AVAILABLE, "Failed to enter passive mode.");
         return;
       }
@@ -1376,7 +1376,7 @@ namespace fineftp
 
                                 if (ec)
                                 {
-                                  std::cerr << "Data write error: " << ec.message() << std::endl;
+                                  me->error_ << "Data write error: " << ec.message() << std::endl;
                                   return;
                                 }
 
@@ -1417,7 +1417,7 @@ namespace fineftp
                                 {
                                   if (ec)
                                   {
-                                    std::cerr << "Data transfer aborted: " << ec.message() << std::endl;
+                                    me->error_ << "Data transfer aborted: " << ec.message() << std::endl;
                                     me->sendFtpMessage(FtpReplyCode::TRANSFER_ABORTED, "Data transfer aborted");
                                     return;
                                   }
diff --git a/fineftp-server/src/server_impl.cpp b/fineftp-server/src/server_impl.cpp
index 3faa6bb..d9def60 100644
--- a/fineftp-server/src/server_impl.cpp
+++ b/fineftp-server/src/server_impl.cpp
@@ -50,7 +50,7 @@ namespace fineftp
     const asio::ip::tcp::endpoint endpoint(asio::ip::make_address(address_, make_address_ec), port_);
     if (make_address_ec)
     {
-      std::cerr << "Error creating address from string \"" << address_<< "\": " << make_address_ec.message() << std::endl;
+      error_ << "Error creating address from string \"" << address_<< "\": " << make_address_ec.message() << std::endl;
       return false;
     }
     
@@ -59,7 +59,7 @@ namespace fineftp
       acceptor_.open(endpoint.protocol(), ec);
       if (ec)
       {
-        std::cerr << "Error opening acceptor: " << ec.message() << std::endl;
+        error_ << "Error opening acceptor: " << ec.message() << std::endl;
         return false;
       }
     }
@@ -69,7 +69,7 @@ namespace fineftp
       acceptor_.set_option(asio::ip::tcp::acceptor::reuse_address(true), ec);
       if (ec)
       {
-        std::cerr << "Error setting reuse_address option: " << ec.message() << std::endl;
+        error_ << "Error setting reuse_address option: " << ec.message() << std::endl;
         return false;
       }
     }
@@ -79,7 +79,7 @@ namespace fineftp
       acceptor_.bind(endpoint, ec);
       if (ec)
       {
-        std::cerr << "Error binding acceptor: " << ec.message() << std::endl;
+        error_ << "Error binding acceptor: " << ec.message() << std::endl;
         return false;
       }
     }
@@ -89,13 +89,13 @@ namespace fineftp
       acceptor_.listen(asio::socket_base::max_listen_connections, ec);
       if (ec)
       {
-        std::cerr << "Error listening on acceptor: " << ec.message() << std::endl;
+        error_ << "Error listening on acceptor: " << ec.message() << std::endl;
         return false;
       }
     }
     
 #ifndef NDEBUG
-    std::cout << "FTP Server created." << std::endl << "Listening at address " << acceptor_.local_endpoint().address() << " on port " << acceptor_.local_endpoint().port() << ":" << std::endl;
+    output_ << "FTP Server created." << std::endl << "Listening at address " << acceptor_.local_endpoint().address() << " on port " << acceptor_.local_endpoint().port() << ":" << std::endl;
 #endif // NDEBUG
 
     acceptor_.async_accept(ftp_session->getSocket()
@@ -129,13 +129,13 @@ namespace fineftp
     if (error)
     {
 #ifndef NDEBUG
-      std::cerr << "Error handling connection: " << error.message() << std::endl;
+      error_ << "Error handling connection: " << error.message() << std::endl;
 #endif
       return;
     }
 
 #ifndef NDEBUG
-    std::cout << "FTP Client connected: " << ftp_session->getSocket().remote_endpoint().address().to_string() << ":" << ftp_session->getSocket().remote_endpoint().port() << std::endl;
+    output_ << "FTP Client connected: " << ftp_session->getSocket().remote_endpoint().address().to_string() << ":" << ftp_session->getSocket().remote_endpoint().port() << std::endl;
 #endif
 
     ftp_session->start();
diff --git a/fineftp-server/src/user_database.cpp b/fineftp-server/src/user_database.cpp
index 8c3ec13..5fd1f22 100644
--- a/fineftp-server/src/user_database.cpp
+++ b/fineftp-server/src/user_database.cpp
@@ -25,14 +25,14 @@ namespace fineftp
     {
       if (anonymous_user_)
       {
-        std::cerr << "Error adding user with username \"" << username << "\". The username denotes the anonymous user, which is already present." << std::endl;
+        error_ << "Error adding user with username \"" << username << "\". The username denotes the anonymous user, which is already present." << std::endl;
         return false;
       }
       else
       {
         anonymous_user_ = std::make_shared<FtpUser>(password, local_root_path, permissions);
 #ifndef NDEBUG
-        std::cout << "Successfully added anonymous user." << std::endl;
+        output_ << "Successfully added anonymous user." << std::endl;
 #endif // !NDEBUG
         return true;
       }
@@ -44,13 +44,13 @@ namespace fineftp
       {
         database_.emplace(username, std::make_shared<FtpUser>(password, local_root_path, permissions));
 #ifndef NDEBUG
-        std::cout << "Successfully added user \"" << username << "\"." << std::endl;
+        output_ << "Successfully added user \"" << username << "\"." << std::endl;
 #endif // !NDEBUG
         return true;
       }
       else
       {
-        std::cerr << "Error adding user with username \"" << username << "\". The user already exists." << std::endl;
+        error_ << "Error adding user with username \"" << username << "\". The user already exists." << std::endl;
         return false;
       }
     }