diff --git a/contrib/epee/include/net/abstract_http_client.h b/contrib/epee/include/net/abstract_http_client.h
index 1f8bbc605..5270824e1 100644
--- a/contrib/epee/include/net/abstract_http_client.h
+++ b/contrib/epee/include/net/abstract_http_client.h
@@ -70,7 +70,7 @@ namespace http
     virtual bool connect(std::chrono::milliseconds timeout) = 0;
     virtual bool disconnect() = 0;
     virtual bool is_connected(bool *ssl = NULL) = 0;
-    virtual bool invoke(const boost::string_ref uri, const boost::string_ref method, const std::string& body, std::chrono::milliseconds timeout, const http_response_info** ppresponse_info = NULL, const fields_list& additional_params = fields_list()) = 0;
+    virtual bool invoke(const boost::string_ref uri, const boost::string_ref method, const boost::string_ref body, std::chrono::milliseconds timeout, const http_response_info** ppresponse_info = NULL, const fields_list& additional_params = fields_list()) = 0;
     virtual bool invoke_get(const boost::string_ref uri, std::chrono::milliseconds timeout, const std::string& body = std::string(), const http_response_info** ppresponse_info = NULL, const fields_list& additional_params = fields_list()) = 0;
     virtual bool invoke_post(const boost::string_ref uri, const std::string& body, std::chrono::milliseconds timeout, const http_response_info** ppresponse_info = NULL, const fields_list& additional_params = fields_list()) = 0;
     virtual uint64_t get_bytes_sent() const = 0;
diff --git a/contrib/epee/include/net/http_client.h b/contrib/epee/include/net/http_client.h
index 9645e896b..3725ef079 100644
--- a/contrib/epee/include/net/http_client.h
+++ b/contrib/epee/include/net/http_client.h
@@ -233,7 +233,7 @@ namespace net_utils
 			}
 
 			//---------------------------------------------------------------------------
-			inline bool invoke(const boost::string_ref uri, const boost::string_ref method, const std::string& body, std::chrono::milliseconds timeout, const http_response_info** ppresponse_info = NULL, const fields_list& additional_params = fields_list()) override
+			inline bool invoke(const boost::string_ref uri, const boost::string_ref method, const boost::string_ref body, std::chrono::milliseconds timeout, const http_response_info** ppresponse_info = NULL, const fields_list& additional_params = fields_list()) override
 			{
 				CRITICAL_REGION_LOCAL(m_lock);
 				if(!is_connected())
diff --git a/contrib/epee/include/net/http_server_handlers_map2.h b/contrib/epee/include/net/http_server_handlers_map2.h
index ac22cd7a9..1665fdac7 100644
--- a/contrib/epee/include/net/http_server_handlers_map2.h
+++ b/contrib/epee/include/net/http_server_handlers_map2.h
@@ -118,8 +118,10 @@
         return true; \
       } \
       uint64_t ticks2 = misc_utils::get_tick_count(); \
-      epee::serialization::store_t_to_binary(static_cast<command_type::response&>(resp), response_info.m_body); \
+      epee::byte_slice buffer; \
+      epee::serialization::store_t_to_binary(static_cast<command_type::response&>(resp), buffer, 64 * 1024); \
       uint64_t ticks3 = epee::misc_utils::get_tick_count(); \
+      response_info.m_body.assign(reinterpret_cast<const char*>(buffer.data()), buffer.size()); \
       response_info.m_mime_tipe = " application/octet-stream"; \
       response_info.m_header_info.m_content_type = " application/octet-stream"; \
       MDEBUG( s_pattern << "() processed with " << ticks1-ticks << "/"<< ticks2-ticks1 << "/" << ticks3-ticks2 << "ms"); \
diff --git a/contrib/epee/include/net/levin_base.h b/contrib/epee/include/net/levin_base.h
index f9b6f9a81..ad561c5b6 100644
--- a/contrib/epee/include/net/levin_base.h
+++ b/contrib/epee/include/net/levin_base.h
@@ -31,7 +31,6 @@
 
 #include <cstdint>
 
-#include "byte_slice.h"
 #include "net_utils_base.h"
 #include "span.h"
 
@@ -39,6 +38,7 @@
 
 namespace epee
 {
+class byte_slice;
 namespace levin
 {
 #pragma pack(push)
@@ -86,7 +86,7 @@ namespace levin
   template<class t_connection_context = net_utils::connection_context_base>
   struct levin_commands_handler
   {
-    virtual int invoke(int command, const epee::span<const uint8_t> in_buff, std::string& buff_out, t_connection_context& context)=0;
+    virtual int invoke(int command, const epee::span<const uint8_t> in_buff, byte_slice& buff_out, t_connection_context& context)=0;
     virtual int notify(int command, const epee::span<const uint8_t> in_buff, t_connection_context& context)=0;
     virtual void callback(t_connection_context& context){};
 
diff --git a/contrib/epee/include/net/levin_protocol_handler_async.h b/contrib/epee/include/net/levin_protocol_handler_async.h
index 1341a4ae6..8cb2be3e1 100644
--- a/contrib/epee/include/net/levin_protocol_handler_async.h
+++ b/contrib/epee/include/net/levin_protocol_handler_async.h
@@ -514,16 +514,15 @@ public:
           {
             if(m_current_head.m_have_to_return_data)
             {
-              std::string return_buff;
+              byte_slice return_buff;
               const uint32_t return_code = m_config.m_pcommands_handler->invoke(
                 m_current_head.m_command, buff_to_invoke, return_buff, m_connection_context
               );
 
               bucket_head2 head = make_header(m_current_head.m_command, return_buff.size(), LEVIN_PACKET_RESPONSE, false);
               head.m_return_code = SWAP32LE(return_code);
-              return_buff.insert(0, reinterpret_cast<const char*>(&head), sizeof(head));
 
-              if(!m_pservice_endpoint->do_send(byte_slice{std::move(return_buff)}))
+              if(!m_pservice_endpoint->do_send(byte_slice{{epee::as_byte_span(head), epee::to_span(return_buff)}}))
                 return false;
 
               MDEBUG(m_connection_context << "LEVIN_PACKET_SENT. [len=" << head.m_cb
diff --git a/contrib/epee/include/net/net_helper.h b/contrib/epee/include/net/net_helper.h
index 9446e3588..508c79d76 100644
--- a/contrib/epee/include/net/net_helper.h
+++ b/contrib/epee/include/net/net_helper.h
@@ -44,6 +44,7 @@
 #include <boost/lambda/lambda.hpp>
 #include <boost/interprocess/detail/atomic.hpp>
 #include <boost/system/error_code.hpp>
+#include <boost/utility/string_ref.hpp>
 #include <functional>
 #include "net/net_utils_base.h"
 #include "net/net_ssl.h"
@@ -280,7 +281,7 @@ namespace net_utils
 
 
 		inline 
-		bool send(const std::string& buff, std::chrono::milliseconds timeout)
+		bool send(const boost::string_ref buff, std::chrono::milliseconds timeout)
 		{
 
 			try
@@ -298,7 +299,7 @@ namespace net_utils
 				// object is used as a callback and will update the ec variable when the
 				// operation completes. The blocking_udp_client.cpp example shows how you
 				// can use boost::bind rather than boost::lambda.
-				async_write(buff.c_str(), buff.size(), ec);
+				async_write(buff.data(), buff.size(), ec);
 
 				// Block until the asynchronous operation has completed.
 				while (ec == boost::asio::error::would_block)
diff --git a/contrib/epee/include/storages/http_abstract_invoke.h b/contrib/epee/include/storages/http_abstract_invoke.h
index a8bc945a8..c4cb91130 100644
--- a/contrib/epee/include/storages/http_abstract_invoke.h
+++ b/contrib/epee/include/storages/http_abstract_invoke.h
@@ -29,6 +29,7 @@
 #include <boost/utility/string_ref.hpp>
 #include <chrono>
 #include <string>
+#include "byte_slice.h"
 #include "portable_storage_template_helper.h"
 #include "net/http_base.h"
 #include "net/http_server_handlers_map2.h"
@@ -74,12 +75,12 @@ namespace epee
     template<class t_request, class t_response, class t_transport>
     bool invoke_http_bin(const boost::string_ref uri, const t_request& out_struct, t_response& result_struct, t_transport& transport, std::chrono::milliseconds timeout = std::chrono::seconds(15), const boost::string_ref method = "POST")
     {
-      std::string req_param;
-      if(!serialization::store_t_to_binary(out_struct, req_param))
+      byte_slice req_param;
+      if(!serialization::store_t_to_binary(out_struct, req_param, 16 * 1024))
         return false;
 
       const http::http_response_info* pri = NULL;
-      if(!transport.invoke(uri, method, req_param, timeout, std::addressof(pri)))
+      if(!transport.invoke(uri, method, boost::string_ref{reinterpret_cast<const char*>(req_param.data()), req_param.size()}, timeout, std::addressof(pri)))
       {
         LOG_PRINT_L1("Failed to invoke http request to  " << uri);
         return false;
diff --git a/contrib/epee/include/storages/levin_abstract_invoke2.h b/contrib/epee/include/storages/levin_abstract_invoke2.h
index cf1262486..95f0bb410 100644
--- a/contrib/epee/include/storages/levin_abstract_invoke2.h
+++ b/contrib/epee/include/storages/levin_abstract_invoke2.h
@@ -27,8 +27,10 @@
 #pragma once
 
 #include "portable_storage_template_helper.h"
+#include <boost/utility/string_ref.hpp>
 #include <boost/utility/value_init.hpp>
 #include <functional>
+#include "byte_slice.h"
 #include "span.h"
 #include "net/levin_base.h"
 
@@ -110,11 +112,12 @@ namespace epee
       const boost::uuids::uuid &conn_id = context.m_connection_id;
       typename serialization::portable_storage stg;
       out_struct.store(stg);
-      std::string buff_to_send, buff_to_recv;
-      stg.store_to_binary(buff_to_send);
+      byte_slice buff_to_send;
+      std::string buff_to_recv;
+      stg.store_to_binary(buff_to_send, 16 * 1024);
 
       on_levin_traffic(context, true, true, false, buff_to_send.size(), command);
-      int res = transport.invoke(command, buff_to_send, buff_to_recv, conn_id);
+      int res = transport.invoke(command, boost::string_ref{reinterpret_cast<const char*>(buff_to_send.data()), buff_to_send.size()}, buff_to_recv, conn_id);
       if( res <=0 )
       {
         LOG_PRINT_L1("Failed to invoke command " << command << " return code " << res);
@@ -137,10 +140,10 @@ namespace epee
       const boost::uuids::uuid &conn_id = context.m_connection_id;
       typename serialization::portable_storage stg;
       const_cast<t_arg&>(out_struct).store(stg);//TODO: add true const support to searilzation
-      std::string buff_to_send;
-      stg.store_to_binary(buff_to_send);
+      byte_slice buff_to_send;
+      stg.store_to_binary(buff_to_send, 16 * 1024);
       on_levin_traffic(context, true, true, false, buff_to_send.size(), command);
-      int res = transport.invoke_async(command, epee::strspan<uint8_t>(buff_to_send), conn_id, [cb, command](int code, const epee::span<const uint8_t> buff, typename t_transport::connection_context& context)->bool 
+      int res = transport.invoke_async(command, epee::to_span(buff_to_send), conn_id, [cb, command](int code, const epee::span<const uint8_t> buff, typename t_transport::connection_context& context)->bool
       {
         t_result result_struct = AUTO_VAL_INIT(result_struct);
         if( code <=0 )
@@ -184,11 +187,11 @@ namespace epee
       const boost::uuids::uuid &conn_id = context.m_connection_id;
       serialization::portable_storage stg;
       out_struct.store(stg);
-      std::string buff_to_send;
+      byte_slice buff_to_send;
       stg.store_to_binary(buff_to_send);
 
       on_levin_traffic(context, true, true, false, buff_to_send.size(), command);
-      int res = transport.notify(command, epee::strspan<uint8_t>(buff_to_send), conn_id);
+      int res = transport.notify(command, epee::to_span(buff_to_send), conn_id);
       if(res <=0 )
       {
         MERROR("Failed to notify command " << command << " return code " << res);
@@ -199,7 +202,7 @@ namespace epee
     //----------------------------------------------------------------------------------------------------
     //----------------------------------------------------------------------------------------------------
     template<class t_owner, class t_in_type, class t_out_type, class t_context, class callback_t>
-    int buff_to_t_adapter(int command, const epee::span<const uint8_t> in_buff, std::string& buff_out, callback_t cb, t_context& context )
+    int buff_to_t_adapter(int command, const epee::span<const uint8_t> in_buff, byte_slice& buff_out, callback_t cb, t_context& context )
     {
       serialization::portable_storage strg;
       if(!strg.load_from_binary(in_buff))
@@ -222,7 +225,7 @@ namespace epee
       serialization::portable_storage strg_out;
       static_cast<t_out_type&>(out_struct).store(strg_out);
 
-      if(!strg_out.store_to_binary(buff_out))
+      if(!strg_out.store_to_binary(buff_out, 32 * 1024))
       {
         LOG_ERROR("Failed to store_to_binary in command" << command);
         return -1;
@@ -254,7 +257,7 @@ namespace epee
     }
 
 #define CHAIN_LEVIN_INVOKE_MAP2(context_type) \
-  int invoke(int command, const epee::span<const uint8_t> in_buff, std::string& buff_out, context_type& context) \
+  int invoke(int command, const epee::span<const uint8_t> in_buff, epee::byte_slice& buff_out, context_type& context) \
   { \
   bool handled = false; \
   return handle_invoke_map(false, command, in_buff, buff_out, context, handled); \
@@ -263,13 +266,13 @@ namespace epee
 #define CHAIN_LEVIN_NOTIFY_MAP2(context_type) \
   int notify(int command, const epee::span<const uint8_t> in_buff, context_type& context) \
   { \
-  bool handled = false; std::string fake_str;\
+  bool handled = false; epee::byte_slice fake_str; \
   return handle_invoke_map(true, command, in_buff, fake_str, context, handled); \
   } 
 
 
 #define CHAIN_LEVIN_INVOKE_MAP() \
-  int invoke(int command, const epee::span<const uint8_t> in_buff, std::string& buff_out, epee::net_utils::connection_context_base& context) \
+  int invoke(int command, const epee::span<const uint8_t> in_buff, epee::byte_slice& buff_out, epee::net_utils::connection_context_base& context) \
   { \
   bool handled = false; \
   return handle_invoke_map(false, command, in_buff, buff_out, context, handled); \
@@ -289,7 +292,7 @@ namespace epee
   } 
 
 #define BEGIN_INVOKE_MAP2(owner_type) \
-  template <class t_context> int handle_invoke_map(bool is_notify, int command, const epee::span<const uint8_t> in_buff, std::string& buff_out, t_context& context, bool& handled) \
+  template <class t_context> int handle_invoke_map(bool is_notify, int command, const epee::span<const uint8_t> in_buff, epee::byte_slice& buff_out, t_context& context, bool& handled) \
   { \
   try { \
   typedef owner_type internal_owner_type_name;
diff --git a/contrib/epee/include/storages/portable_storage.h b/contrib/epee/include/storages/portable_storage.h
index 4b759a24f..589e6ad63 100644
--- a/contrib/epee/include/storages/portable_storage.h
+++ b/contrib/epee/include/storages/portable_storage.h
@@ -32,7 +32,6 @@
 
 #include "misc_language.h"
 #include "portable_storage_base.h"
-#include "portable_storage_to_bin.h"
 #include "portable_storage_from_bin.h"
 #include "portable_storage_to_json.h"
 #include "portable_storage_from_json.h"
@@ -42,6 +41,7 @@
 
 namespace epee
 {
+  class byte_slice;
   namespace serialization
   {
     /************************************************************************/
@@ -83,7 +83,7 @@ namespace epee
       bool        delete_entry(const std::string& pentry_name, hsection hparent_section = nullptr);
 
       //-------------------------------------------------------------------------------
-      bool		store_to_binary(binarybuffer& target);
+      bool		store_to_binary(byte_slice& target, std::size_t initial_buffer_size = 8192);
       bool		load_from_binary(const epee::span<const uint8_t> target);
       bool		load_from_binary(const std::string& target) { return load_from_binary(epee::strspan<uint8_t>(target)); }
       template<class trace_policy>
@@ -133,22 +133,6 @@ namespace epee
     {
       return false;//TODO: don't think i ever again will use xml - ambiguous and "overtagged" format
     }
-
-    inline
-    bool portable_storage::store_to_binary(binarybuffer& target)
-    {
-      TRY_ENTRY();
-      std::stringstream ss;
-      storage_block_header sbh = AUTO_VAL_INIT(sbh);
-      sbh.m_signature_a = SWAP32LE(PORTABLE_STORAGE_SIGNATUREA);
-      sbh.m_signature_b = SWAP32LE(PORTABLE_STORAGE_SIGNATUREB);
-      sbh.m_ver = PORTABLE_STORAGE_FORMAT_VER;
-      ss.write((const char*)&sbh, sizeof(storage_block_header));
-      pack_entry_to_buff(ss, m_root);
-      target = ss.str();
-      return true;
-      CATCH_ENTRY("portable_storage::store_to_binary", false)
-    }
     inline
     bool portable_storage::load_from_binary(const epee::span<const uint8_t> source)
     {
diff --git a/contrib/epee/include/storages/portable_storage_template_helper.h b/contrib/epee/include/storages/portable_storage_template_helper.h
index 13c870d44..39f900c8d 100644
--- a/contrib/epee/include/storages/portable_storage_template_helper.h
+++ b/contrib/epee/include/storages/portable_storage_template_helper.h
@@ -28,6 +28,7 @@
 
 #include <string>
 
+#include "byte_slice.h"
 #include "parserse_base_utils.h"
 #include "portable_storage.h"
 #include "file_io_utils.h"
@@ -111,18 +112,18 @@ namespace epee
     }
     //-----------------------------------------------------------------------------------------------------------
     template<class t_struct>
-    bool store_t_to_binary(t_struct& str_in, std::string& binary_buff, size_t indent = 0)
+    bool store_t_to_binary(t_struct& str_in, byte_slice& binary_buff, size_t initial_buffer_size = 8192)
     {
       portable_storage ps;
       str_in.store(ps);
-      return ps.store_to_binary(binary_buff);
+      return ps.store_to_binary(binary_buff, initial_buffer_size);
     }
     //-----------------------------------------------------------------------------------------------------------
     template<class t_struct>
-    std::string store_t_to_binary(t_struct& str_in, size_t indent = 0)
+    byte_slice store_t_to_binary(t_struct& str_in, size_t initial_buffer_size = 8192)
     {
-      std::string binary_buff;
-      store_t_to_binary(str_in, binary_buff, indent);
+      byte_slice binary_buff;
+      store_t_to_binary(str_in, binary_buff, initial_buffer_size);
       return binary_buff;
     }
   }
diff --git a/contrib/epee/src/CMakeLists.txt b/contrib/epee/src/CMakeLists.txt
index 8adf69162..5e101a86a 100644
--- a/contrib/epee/src/CMakeLists.txt
+++ b/contrib/epee/src/CMakeLists.txt
@@ -29,7 +29,7 @@
 
 add_library(epee STATIC byte_slice.cpp byte_stream.cpp hex.cpp abstract_http_client.cpp http_auth.cpp mlog.cpp net_helper.cpp net_utils_base.cpp string_tools.cpp
     wipeable_string.cpp levin_base.cpp memwipe.c connection_basic.cpp network_throttle.cpp network_throttle-detail.cpp mlocker.cpp buffer.cpp net_ssl.cpp
-    int-util.cpp)
+    int-util.cpp portable_storage.cpp)
 
 if (USE_READLINE AND (GNU_READLINE_FOUND OR (DEPENDS AND NOT MINGW)))
   add_library(epee_readline STATIC readline_buffer.cpp)
diff --git a/contrib/epee/src/portable_storage.cpp b/contrib/epee/src/portable_storage.cpp
new file mode 100644
index 000000000..4534deff3
--- /dev/null
+++ b/contrib/epee/src/portable_storage.cpp
@@ -0,0 +1,29 @@
+
+#include "byte_slice.h"
+#include "byte_stream.h"
+#include "misc_log_ex.h"
+#include "span.h"
+#include "storages/portable_storage.h"
+#include "storages/portable_storage_to_bin.h"
+
+namespace epee
+{
+namespace serialization
+{
+  bool portable_storage::store_to_binary(byte_slice& target, const std::size_t initial_buffer_size)
+  {
+    TRY_ENTRY();
+    byte_stream ss;
+    ss.reserve(initial_buffer_size);
+    storage_block_header sbh{};
+    sbh.m_signature_a = SWAP32LE(PORTABLE_STORAGE_SIGNATUREA);
+    sbh.m_signature_b = SWAP32LE(PORTABLE_STORAGE_SIGNATUREB);
+    sbh.m_ver = PORTABLE_STORAGE_FORMAT_VER;
+    ss.write(epee::as_byte_span(sbh));
+    pack_entry_to_buff(ss, m_root);
+    target = epee::byte_slice{std::move(ss)};
+    return true;
+    CATCH_ENTRY("portable_storage::store_to_binary", false)
+  }
+}
+}
diff --git a/src/cryptonote_protocol/cryptonote_protocol_handler.h b/src/cryptonote_protocol/cryptonote_protocol_handler.h
index ee3a67198..7093f7826 100644
--- a/src/cryptonote_protocol/cryptonote_protocol_handler.h
+++ b/src/cryptonote_protocol/cryptonote_protocol_handler.h
@@ -37,6 +37,7 @@
 #include <boost/program_options/variables_map.hpp>
 #include <string>
 
+#include "byte_slice.h"
 #include "math_helper.h"
 #include "storages/levin_abstract_invoke2.h"
 #include "warnings.h"
@@ -100,7 +101,7 @@ namespace cryptonote
     void set_p2p_endpoint(nodetool::i_p2p_endpoint<connection_context>* p2p);
     //bool process_handshake_data(const blobdata& data, cryptonote_connection_context& context);
     bool process_payload_sync_data(const CORE_SYNC_DATA& hshd, cryptonote_connection_context& context, bool is_inital);
-    bool get_payload_sync_data(blobdata& data);
+    bool get_payload_sync_data(epee::byte_slice& data);
     bool get_payload_sync_data(CORE_SYNC_DATA& hshd);
     bool on_callback(cryptonote_connection_context& context);
     t_core& get_core(){return m_core;}
@@ -191,10 +192,10 @@ namespace cryptonote
       bool post_notify(typename t_parameter::request& arg, cryptonote_connection_context& context)
       {
         LOG_PRINT_L2("[" << epee::net_utils::print_connection_context_short(context) << "] post " << typeid(t_parameter).name() << " -->");
-        std::string blob;
-        epee::serialization::store_t_to_binary(arg, blob);
+        epee::byte_slice blob;
+        epee::serialization::store_t_to_binary(arg, blob, 256 * 1024); // optimize for block responses
         //handler_response_blocks_now(blob.size()); // XXX
-        return m_p2p->invoke_notify_to_peer(t_parameter::ID, epee::strspan<uint8_t>(blob), context);
+        return m_p2p->invoke_notify_to_peer(t_parameter::ID, epee::to_span(blob), context);
       }
   };
 
diff --git a/src/cryptonote_protocol/cryptonote_protocol_handler.inl b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
index c62a0cd31..f25f9e134 100644
--- a/src/cryptonote_protocol/cryptonote_protocol_handler.inl
+++ b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
@@ -425,7 +425,7 @@ namespace cryptonote
   }
   //------------------------------------------------------------------------------------------------------------------------
     template<class t_core>
-    bool t_cryptonote_protocol_handler<t_core>::get_payload_sync_data(blobdata& data)
+    bool t_cryptonote_protocol_handler<t_core>::get_payload_sync_data(epee::byte_slice& data)
   {
     CORE_SYNC_DATA hsd = {};
     get_payload_sync_data(hsd);
@@ -2585,15 +2585,15 @@ skip:
     // send fluffy ones first, we want to encourage people to run that
     if (!fluffyConnections.empty())
     {
-      std::string fluffyBlob;
-      epee::serialization::store_t_to_binary(fluffy_arg, fluffyBlob);
-      m_p2p->relay_notify_to_list(NOTIFY_NEW_FLUFFY_BLOCK::ID, epee::strspan<uint8_t>(fluffyBlob), std::move(fluffyConnections));
+      epee::byte_slice fluffyBlob;
+      epee::serialization::store_t_to_binary(fluffy_arg, fluffyBlob, 32 * 1024);
+      m_p2p->relay_notify_to_list(NOTIFY_NEW_FLUFFY_BLOCK::ID, epee::to_span(fluffyBlob), std::move(fluffyConnections));
     }
     if (!fullConnections.empty())
     {
-      std::string fullBlob;
-      epee::serialization::store_t_to_binary(arg, fullBlob);
-      m_p2p->relay_notify_to_list(NOTIFY_NEW_BLOCK::ID, epee::strspan<uint8_t>(fullBlob), std::move(fullConnections));
+      epee::byte_slice fullBlob;
+      epee::serialization::store_t_to_binary(arg, fullBlob, 128 * 1024);
+      m_p2p->relay_notify_to_list(NOTIFY_NEW_BLOCK::ID, epee::to_span(fullBlob), std::move(fullConnections));
     }
 
     return true;
diff --git a/src/cryptonote_protocol/levin_notify.cpp b/src/cryptonote_protocol/levin_notify.cpp
index 2d04dffb6..318bcf4e1 100644
--- a/src/cryptonote_protocol/levin_notify.cpp
+++ b/src/cryptonote_protocol/levin_notify.cpp
@@ -36,6 +36,7 @@
 #include <stdexcept>
 #include <utility>
 
+#include "byte_slice.h"
 #include "common/expect.h"
 #include "common/varint.h"
 #include "cryptonote_config.h"
@@ -52,7 +53,7 @@
 
 namespace
 {
-  int get_command_from_message(const cryptonote::blobdata &msg)
+  int get_command_from_message(const epee::byte_slice &msg)
   {
     return msg.size() >= sizeof(epee::levin::bucket_head2) ? SWAP32LE(((epee::levin::bucket_head2*)msg.data())->m_command) : 0;
   }
@@ -166,7 +167,7 @@ namespace levin
       return get_out_connections(p2p, get_blockchain_height(p2p, core));
     }
 
-    std::string make_tx_payload(std::vector<blobdata>&& txs, const bool pad, const bool fluff)
+    epee::byte_slice make_tx_payload(std::vector<blobdata>&& txs, const bool pad, const bool fluff)
     {
       NOTIFY_NEW_TRANSACTIONS::request request{};
       request.txs = std::move(txs);
@@ -188,7 +189,7 @@ namespace levin
           padding -= overhead;
         request._ = std::string(padding, ' ');
 
-        std::string arg_buff;
+        epee::byte_slice arg_buff;
         epee::serialization::store_t_to_binary(request, arg_buff);
 
         // we probably lowballed the payload size a bit, so added a but too much. Fix this now.
@@ -200,7 +201,7 @@ namespace levin
         // if the size of _ moved enough, we might lose byte in size encoding, we don't care
       }
 
-      std::string fullBlob;
+      epee::byte_slice fullBlob;
       if (!epee::serialization::store_t_to_binary(request, fullBlob))
         throw std::runtime_error{"Failed to serialize to epee binary format"};
 
@@ -209,12 +210,12 @@ namespace levin
 
     bool make_payload_send_txs(connections& p2p, std::vector<blobdata>&& txs, const boost::uuids::uuid& destination, const bool pad, const bool fluff)
     {
-      const cryptonote::blobdata blob = make_tx_payload(std::move(txs), pad, fluff);
+      const epee::byte_slice blob = make_tx_payload(std::move(txs), pad, fluff);
       p2p.for_connection(destination, [&blob](detail::p2p_context& context) {
         on_levin_traffic(context, true, true, false, blob.size(), get_command_from_message(blob));
         return true;
       });
-      return p2p.notify(NOTIFY_NEW_TRANSACTIONS::ID, epee::strspan<std::uint8_t>(blob), destination);
+      return p2p.notify(NOTIFY_NEW_TRANSACTIONS::ID, epee::to_span(blob), destination);
     }
 
     /* The current design uses `asio::strand`s. The documentation isn't as clear
@@ -825,9 +826,9 @@ namespace levin
 
       // Padding is not useful when using noise mode. Send as stem so receiver
       // forwards in Dandelion++ mode.
-      const std::string payload = make_tx_payload(std::move(txs), false, false);
+      const epee::byte_slice payload = make_tx_payload(std::move(txs), false, false);
       epee::byte_slice message = epee::levin::make_fragmented_notify(
-        zone_->noise, NOTIFY_NEW_TRANSACTIONS::ID, epee::strspan<std::uint8_t>(payload)
+        zone_->noise, NOTIFY_NEW_TRANSACTIONS::ID, epee::to_span(payload)
       );
       if (CRYPTONOTE_MAX_FRAGMENTS * zone_->noise.size() < message.size())
       {
diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index 920e0413c..91b3c0535 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -3788,7 +3788,7 @@ bool wallet2::store_keys(const std::string& keys_file_name, const epee::wipeable
 //----------------------------------------------------------------------------------------------------
 boost::optional<wallet2::keys_file_data> wallet2::get_keys_file_data(const epee::wipeable_string& password, bool watch_only)
 {
-  std::string account_data;
+  epee::byte_slice account_data;
   std::string multisig_signers;
   std::string multisig_derivations;
   cryptonote::account_base account = m_account;
@@ -3815,7 +3815,7 @@ boost::optional<wallet2::keys_file_data> wallet2::get_keys_file_data(const epee:
   rapidjson::Document json;
   json.SetObject();
   rapidjson::Value value(rapidjson::kStringType);
-  value.SetString(account_data.c_str(), account_data.length());
+  value.SetString(reinterpret_cast<const char*>(account_data.data()), account_data.size());
   json.AddMember("key_data", value, json.GetAllocator());
   if (!seed_language.empty())
   {
@@ -3989,13 +3989,12 @@ boost::optional<wallet2::keys_file_data> wallet2::get_keys_file_data(const epee:
   rapidjson::StringBuffer buffer;
   rapidjson::Writer<rapidjson::StringBuffer> writer(buffer);
   json.Accept(writer);
-  account_data = buffer.GetString();
 
   // Encrypt the entire JSON object.
   std::string cipher;
-  cipher.resize(account_data.size());
+  cipher.resize(buffer.GetSize());
   keys_file_data.get().iv = crypto::rand<crypto::chacha_iv>();
-  crypto::chacha20(account_data.data(), account_data.size(), key, keys_file_data.get().iv, &cipher[0]);
+  crypto::chacha20(buffer.GetString(), buffer.GetSize(), key, keys_file_data.get().iv, &cipher[0]);
   keys_file_data.get().account_data = cipher;
   return keys_file_data;
 }
diff --git a/tests/fuzz/http-client.cpp b/tests/fuzz/http-client.cpp
index 4b12b36bb..65df24a3f 100644
--- a/tests/fuzz/http-client.cpp
+++ b/tests/fuzz/http-client.cpp
@@ -26,6 +26,7 @@
 // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+#include <boost/utility/string_ref.hpp>
 #include "include_base_utils.h"
 #include "file_io_utils.h"
 #include "net/http_client.h"
@@ -38,7 +39,7 @@ public:
   bool connect(const std::string& addr, int port, std::chrono::milliseconds timeout, bool ssl = false, const std::string& bind_ip = "0.0.0.0") { return true; }
   bool connect(const std::string& addr, const std::string& port, std::chrono::milliseconds timeout, bool ssl = false, const std::string& bind_ip = "0.0.0.0") { return true; }
   bool disconnect() { return true; }
-  bool send(const std::string& buff, std::chrono::milliseconds timeout) { return true; }
+  bool send(const boost::string_ref buff, std::chrono::milliseconds timeout) { return true; }
   bool send(const void* data, size_t sz) { return true; }
   bool is_connected() { return true; }
   bool recv(std::string& buff, std::chrono::milliseconds timeout)
diff --git a/tests/fuzz/levin.cpp b/tests/fuzz/levin.cpp
index 012d05f36..b090c350b 100644
--- a/tests/fuzz/levin.cpp
+++ b/tests/fuzz/levin.cpp
@@ -65,13 +65,13 @@ namespace
     {
     }
 
-    virtual int invoke(int command, const epee::span<const uint8_t> in_buff, std::string& buff_out, test_levin_connection_context& context)
+    virtual int invoke(int command, const epee::span<const uint8_t> in_buff, epee::byte_slice& buff_out, test_levin_connection_context& context)
     {
       m_invoke_counter.inc();
       boost::unique_lock<boost::mutex> lock(m_mutex);
       m_last_command = command;
       m_last_in_buf = std::string((const char*)in_buff.data(), in_buff.size());
-      buff_out = m_invoke_out_buf;
+      buff_out = m_invoke_out_buf.clone();
       return m_return_code;
     }
 
@@ -111,8 +111,7 @@ namespace
     int return_code() const { return m_return_code; }
     void return_code(int v) { m_return_code = v; }
 
-    const std::string& invoke_out_buf() const { return m_invoke_out_buf; }
-    void invoke_out_buf(const std::string& v) { m_invoke_out_buf = v; }
+    void invoke_out_buf(std::string v) { m_invoke_out_buf = epee::byte_slice{std::move(v)}; }
 
     int last_command() const { return m_last_command; }
     const std::string& last_in_buf() const { return m_last_in_buf; }
@@ -127,7 +126,7 @@ namespace
     boost::mutex m_mutex;
 
     int m_return_code;
-    std::string m_invoke_out_buf;
+    epee::byte_slice m_invoke_out_buf;
 
     int m_last_command;
     std::string m_last_in_buf;
diff --git a/tests/net_load_tests/net_load_tests.h b/tests/net_load_tests/net_load_tests.h
index 882d42c02..e7e0ee247 100644
--- a/tests/net_load_tests/net_load_tests.h
+++ b/tests/net_load_tests/net_load_tests.h
@@ -64,7 +64,7 @@ namespace net_load_tests
     {
     }
 
-    virtual int invoke(int command, const epee::span<const uint8_t> in_buff, std::string& buff_out, test_connection_context& context)
+    virtual int invoke(int command, const epee::span<const uint8_t> in_buff, epee::byte_slice& buff_out, test_connection_context& context)
     {
       //m_invoke_counter.inc();
       //std::unique_lock<std::mutex> lock(m_mutex);
diff --git a/tests/unit_tests/epee_levin_protocol_handler_async.cpp b/tests/unit_tests/epee_levin_protocol_handler_async.cpp
index 314fcf9f2..ab6791324 100644
--- a/tests/unit_tests/epee_levin_protocol_handler_async.cpp
+++ b/tests/unit_tests/epee_levin_protocol_handler_async.cpp
@@ -56,13 +56,13 @@ namespace
     {
     }
 
-    virtual int invoke(int command, const epee::span<const uint8_t> in_buff, std::string& buff_out, test_levin_connection_context& context)
+    virtual int invoke(int command, const epee::span<const uint8_t> in_buff, epee::byte_slice& buff_out, test_levin_connection_context& context)
     {
       m_invoke_counter.inc();
       boost::unique_lock<boost::mutex> lock(m_mutex);
       m_last_command = command;
       m_last_in_buf = std::string((const char*)in_buff.data(), in_buff.size());
-      buff_out = m_invoke_out_buf;
+      buff_out = m_invoke_out_buf.clone();
       return m_return_code;
     }
 
@@ -102,8 +102,7 @@ namespace
     int return_code() const { return m_return_code; }
     void return_code(int v) { m_return_code = v; }
 
-    const std::string& invoke_out_buf() const { return m_invoke_out_buf; }
-    void invoke_out_buf(const std::string& v) { m_invoke_out_buf = v; }
+    void invoke_out_buf(std::string v) { m_invoke_out_buf = epee::byte_slice{std::move(v)}; }
 
     int last_command() const { return m_last_command; }
     const std::string& last_in_buf() const { return m_last_in_buf; }
@@ -118,7 +117,7 @@ namespace
     boost::mutex m_mutex;
 
     int m_return_code;
-    std::string m_invoke_out_buf;
+    epee::byte_slice m_invoke_out_buf;
 
     int m_last_command;
     std::string m_last_in_buf;
diff --git a/tests/unit_tests/levin.cpp b/tests/unit_tests/levin.cpp
index 22638942d..2ad149afe 100644
--- a/tests/unit_tests/levin.cpp
+++ b/tests/unit_tests/levin.cpp
@@ -238,9 +238,9 @@ namespace
             return {connection, std::move(request)};
         }
 
-        virtual int invoke(int command, const epee::span<const uint8_t> in_buff, std::string& buff_out, cryptonote::levin::detail::p2p_context& context) override final
+        virtual int invoke(int command, const epee::span<const uint8_t> in_buff, epee::byte_slice& buff_out, cryptonote::levin::detail::p2p_context& context) override final
         {
-            buff_out.clear();
+            buff_out = nullptr;
             invoked_.push_back(
                 {context.m_connection_id, command, std::string{reinterpret_cast<const char*>(in_buff.data()), in_buff.size()}}
             );
diff --git a/tests/unit_tests/net.cpp b/tests/unit_tests/net.cpp
index f5aef4796..dffda5e4e 100644
--- a/tests/unit_tests/net.cpp
+++ b/tests/unit_tests/net.cpp
@@ -245,7 +245,7 @@ namespace
 
 TEST(tor_address, epee_serializev_v2)
 {
-    std::string buffer{};
+    epee::byte_slice buffer{};
     {
         test_command_tor command{MONERO_UNWRAP(net::tor_address::make(v2_onion, 10))};
         EXPECT_FALSE(command.tor.is_unknown());
@@ -266,7 +266,7 @@ TEST(tor_address, epee_serializev_v2)
         EXPECT_EQ(0u, command.tor.port());
 
         epee::serialization::portable_storage stg{};
-        EXPECT_TRUE(stg.load_from_binary(buffer));
+        EXPECT_TRUE(stg.load_from_binary(epee::to_span(buffer)));
         EXPECT_TRUE(command.load(stg));
     }
     EXPECT_FALSE(command.tor.is_unknown());
@@ -277,7 +277,7 @@ TEST(tor_address, epee_serializev_v2)
     // make sure that exceeding max buffer doesn't destroy tor_address::_load
     {
         epee::serialization::portable_storage stg{};
-        stg.load_from_binary(buffer);
+        stg.load_from_binary(epee::to_span(buffer));
 
         std::string host{};
         ASSERT_TRUE(stg.get_value("host", host, stg.open_section("tor", nullptr, false)));
@@ -296,7 +296,7 @@ TEST(tor_address, epee_serializev_v2)
 
 TEST(tor_address, epee_serializev_v3)
 {
-    std::string buffer{};
+    epee::byte_slice buffer{};
     {
         test_command_tor command{MONERO_UNWRAP(net::tor_address::make(v3_onion, 10))};
         EXPECT_FALSE(command.tor.is_unknown());
@@ -317,7 +317,7 @@ TEST(tor_address, epee_serializev_v3)
         EXPECT_EQ(0u, command.tor.port());
 
         epee::serialization::portable_storage stg{};
-        EXPECT_TRUE(stg.load_from_binary(buffer));
+        EXPECT_TRUE(stg.load_from_binary(epee::to_span(buffer)));
         EXPECT_TRUE(command.load(stg));
     }
     EXPECT_FALSE(command.tor.is_unknown());
@@ -328,7 +328,7 @@ TEST(tor_address, epee_serializev_v3)
     // make sure that exceeding max buffer doesn't destroy tor_address::_load
     {
         epee::serialization::portable_storage stg{};
-        stg.load_from_binary(buffer);
+        stg.load_from_binary(epee::to_span(buffer));
 
         std::string host{};
         ASSERT_TRUE(stg.get_value("host", host, stg.open_section("tor", nullptr, false)));
@@ -347,7 +347,7 @@ TEST(tor_address, epee_serializev_v3)
 
 TEST(tor_address, epee_serialize_unknown)
 {
-    std::string buffer{};
+    epee::byte_slice buffer{};
     {
         test_command_tor command{net::tor_address::unknown()};
         EXPECT_TRUE(command.tor.is_unknown());
@@ -368,7 +368,7 @@ TEST(tor_address, epee_serialize_unknown)
         EXPECT_EQ(0u, command.tor.port());
 
         epee::serialization::portable_storage stg{};
-        EXPECT_TRUE(stg.load_from_binary(buffer));
+        EXPECT_TRUE(stg.load_from_binary(epee::to_span(buffer)));
         EXPECT_TRUE(command.load(stg));
     }
     EXPECT_TRUE(command.tor.is_unknown());
@@ -379,7 +379,7 @@ TEST(tor_address, epee_serialize_unknown)
     // make sure that exceeding max buffer doesn't destroy tor_address::_load
     {
         epee::serialization::portable_storage stg{};
-        stg.load_from_binary(buffer);
+        stg.load_from_binary(epee::to_span(buffer));
 
         std::string host{};
         ASSERT_TRUE(stg.get_value("host", host, stg.open_section("tor", nullptr, false)));
@@ -700,7 +700,7 @@ namespace
 
 TEST(i2p_address, epee_serializev_b32)
 {
-    std::string buffer{};
+    epee::byte_slice buffer{};
     {
         test_command_i2p command{MONERO_UNWRAP(net::i2p_address::make(b32_i2p, 10))};
         EXPECT_FALSE(command.i2p.is_unknown());
@@ -721,7 +721,7 @@ TEST(i2p_address, epee_serializev_b32)
         EXPECT_EQ(0u, command.i2p.port());
 
         epee::serialization::portable_storage stg{};
-        EXPECT_TRUE(stg.load_from_binary(buffer));
+        EXPECT_TRUE(stg.load_from_binary(epee::to_span(buffer)));
         EXPECT_TRUE(command.load(stg));
     }
     EXPECT_FALSE(command.i2p.is_unknown());
@@ -732,7 +732,7 @@ TEST(i2p_address, epee_serializev_b32)
     // make sure that exceeding max buffer doesn't destroy i2p_address::_load
     {
         epee::serialization::portable_storage stg{};
-        stg.load_from_binary(buffer);
+        stg.load_from_binary(epee::to_span(buffer));
 
         std::string host{};
         ASSERT_TRUE(stg.get_value("host", host, stg.open_section("i2p", nullptr, false)));
@@ -751,7 +751,7 @@ TEST(i2p_address, epee_serializev_b32)
 
 TEST(i2p_address, epee_serialize_unknown)
 {
-    std::string buffer{};
+    epee::byte_slice buffer{};
     {
         test_command_i2p command{net::i2p_address::unknown()};
         EXPECT_TRUE(command.i2p.is_unknown());
@@ -772,7 +772,7 @@ TEST(i2p_address, epee_serialize_unknown)
         EXPECT_EQ(0u, command.i2p.port());
 
         epee::serialization::portable_storage stg{};
-        EXPECT_TRUE(stg.load_from_binary(buffer));
+        EXPECT_TRUE(stg.load_from_binary(epee::to_span(buffer)));
         EXPECT_TRUE(command.load(stg));
     }
     EXPECT_TRUE(command.i2p.is_unknown());
@@ -783,7 +783,7 @@ TEST(i2p_address, epee_serialize_unknown)
     // make sure that exceeding max buffer doesn't destroy i2p_address::_load
     {
         epee::serialization::portable_storage stg{};
-        stg.load_from_binary(buffer);
+        stg.load_from_binary(epee::to_span(buffer));
 
         std::string host{};
         ASSERT_TRUE(stg.get_value("host", host, stg.open_section("i2p", nullptr, false)));
diff --git a/tests/unit_tests/test_protocol_pack.cpp b/tests/unit_tests/test_protocol_pack.cpp
index 312f18dfe..1a4fd30f8 100644
--- a/tests/unit_tests/test_protocol_pack.cpp
+++ b/tests/unit_tests/test_protocol_pack.cpp
@@ -36,7 +36,7 @@
 
 TEST(protocol_pack, protocol_pack_command) 
 {
-  std::string buff;
+  epee::byte_slice buff;
   cryptonote::NOTIFY_RESPONSE_CHAIN_ENTRY::request r;
   r.start_height = 1;
   r.total_height = 3;
@@ -47,7 +47,7 @@ TEST(protocol_pack, protocol_pack_command)
     ASSERT_TRUE(res);
 
     cryptonote::NOTIFY_RESPONSE_CHAIN_ENTRY::request r2;
-    res = epee::serialization::load_t_from_binary(r2, buff);
+    res = epee::serialization::load_t_from_binary(r2, epee::to_span(buff));
     ASSERT_TRUE(res);
     ASSERT_TRUE(r.m_block_ids.size() == i);
     ASSERT_TRUE(r.start_height == 1);