Various improvements to the ZMQ JSON-RPC handling:

  - Finding handling function in ZMQ JSON-RPC now uses binary search
  - Temporary `std::vector`s in JSON output now use `epee::span` to
    prevent allocations.
  - Binary -> hex in JSON output no longer allocates temporary buffer
  - C++ structs -> JSON skips intermediate DOM creation, and instead
    write directly to an output stream.

3 files changed, 428 insertions, 356 deletions

diff --git a/src/serialization/CMakeLists.txt b/src/serialization/CMakeLists.txt
index 28b775a37..0b231f156 100644
--- a/src/serialization/CMakeLists.txt
+++ b/src/serialization/CMakeLists.txt
@@ -44,6 +44,7 @@ target_link_libraries(serialization
   LINK_PRIVATE
     cryptonote_core
     cryptonote_protocol
+    epee
     ${Boost_CHRONO_LIBRARY}
     ${Boost_REGEX_LIBRARY}
     ${Boost_SYSTEM_LIBRARY}
diff --git a/src/serialization/json_object.cpp b/src/serialization/json_object.cpp
index ea67209dc..e98ba0483 100644
--- a/src/serialization/json_object.cpp
+++ b/src/serialization/json_object.cpp
@@ -109,9 +109,14 @@ namespace
   }
 }
 
-void toJsonValue(rapidjson::Document& doc, const std::string& i, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rapidjson::Value& src)
 {
-  val = rapidjson::Value(i.c_str(), doc.GetAllocator());
+  src.Accept(dest);
+}
+
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const boost::string_ref i)
+{
+  dest.String(i.data(), i.size());
 }
 
 void fromJsonValue(const rapidjson::Value& val, std::string& str)
@@ -124,9 +129,9 @@ void fromJsonValue(const rapidjson::Value& val, std::string& str)
   str = val.GetString();
 }
 
-void toJsonValue(rapidjson::Document& doc, bool i, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, bool i)
 {
-  val.SetBool(i);
+  dest.Bool(i);
 }
 
 void fromJsonValue(const rapidjson::Value& val, bool& b)
@@ -163,9 +168,9 @@ void fromJsonValue(const rapidjson::Value& val, short& i)
   to_int(val, i);
 }
 
-void toJsonValue(rapidjson::Document& doc, const unsigned int i, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const unsigned int i)
 {
-  val = rapidjson::Value(i);
+  dest.Uint(i);
 }
 
 void fromJsonValue(const rapidjson::Value& val, unsigned int& i)
@@ -173,9 +178,9 @@ void fromJsonValue(const rapidjson::Value& val, unsigned int& i)
   to_uint(val, i);
 }
 
-void toJsonValue(rapidjson::Document& doc, const int i, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const int i)
 {
-  val = rapidjson::Value(i);
+  dest.Int(i);
 }
 
 void fromJsonValue(const rapidjson::Value& val, int& i)
@@ -183,10 +188,10 @@ void fromJsonValue(const rapidjson::Value& val, int& i)
   to_int(val, i);
 }
 
-void toJsonValue(rapidjson::Document& doc, const unsigned long long i, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const unsigned long long i)
 {
-  static_assert(!precision_loss<unsigned long long, std::uint64_t>(), "precision loss");
-  val = rapidjson::Value(std::uint64_t(i));
+  static_assert(std::numeric_limits<unsigned long long>::max() <= std::numeric_limits<std::uint64_t>::max(), "bad uint64 conversion");
+  dest.Uint64(i);
 }
 
 void fromJsonValue(const rapidjson::Value& val, unsigned long long& i)
@@ -194,10 +199,11 @@ void fromJsonValue(const rapidjson::Value& val, unsigned long long& i)
   to_uint64(val, i);
 }
 
-void toJsonValue(rapidjson::Document& doc, const long long i, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const long long i)
 {
-  static_assert(!precision_loss<long long, std::int64_t>(), "precision loss");
-  val = rapidjson::Value(std::int64_t(i));
+  static_assert(std::numeric_limits<std::uint64_t>::min() <= std::numeric_limits<long long>::min(), "bad int64 conversion");
+  static_assert(std::numeric_limits<long long>::max() <= std::numeric_limits<std::uint64_t>::max(), "bad int64 conversion");
+  dest.Int64(i);
 }
 
 void fromJsonValue(const rapidjson::Value& val, long long& i)
@@ -215,17 +221,19 @@ void fromJsonValue(const rapidjson::Value& val, long& i)
   to_int64(val, i);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::transaction& tx, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::transaction& tx)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, version, tx.version);
-  INSERT_INTO_JSON_OBJECT(val, doc, unlock_time, tx.unlock_time);
-  INSERT_INTO_JSON_OBJECT(val, doc, inputs, tx.vin);
-  INSERT_INTO_JSON_OBJECT(val, doc, outputs, tx.vout);
-  INSERT_INTO_JSON_OBJECT(val, doc, extra, tx.extra);
-  INSERT_INTO_JSON_OBJECT(val, doc, signatures, tx.signatures);
-  INSERT_INTO_JSON_OBJECT(val, doc, ringct, tx.rct_signatures);
+  INSERT_INTO_JSON_OBJECT(dest, version, tx.version);
+  INSERT_INTO_JSON_OBJECT(dest, unlock_time, tx.unlock_time);
+  INSERT_INTO_JSON_OBJECT(dest, inputs, tx.vin);
+  INSERT_INTO_JSON_OBJECT(dest, outputs, tx.vout);
+  INSERT_INTO_JSON_OBJECT(dest, extra, tx.extra);
+  INSERT_INTO_JSON_OBJECT(dest, signatures, tx.signatures);
+  INSERT_INTO_JSON_OBJECT(dest, ringct, tx.rct_signatures);
+
+  dest.EndObject();
 }
 
 
@@ -245,17 +253,19 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::transaction& tx)
   GET_FROM_JSON_OBJECT(val, tx.rct_signatures, ringct);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::block& b, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::block& b)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, major_version, b.major_version);
+  INSERT_INTO_JSON_OBJECT(dest, minor_version, b.minor_version);
+  INSERT_INTO_JSON_OBJECT(dest, timestamp, b.timestamp);
+  INSERT_INTO_JSON_OBJECT(dest, prev_id, b.prev_id);
+  INSERT_INTO_JSON_OBJECT(dest, nonce, b.nonce);
+  INSERT_INTO_JSON_OBJECT(dest, miner_tx, b.miner_tx);
+  INSERT_INTO_JSON_OBJECT(dest, tx_hashes, b.tx_hashes);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, major_version, b.major_version);
-  INSERT_INTO_JSON_OBJECT(val, doc, minor_version, b.minor_version);
-  INSERT_INTO_JSON_OBJECT(val, doc, timestamp, b.timestamp);
-  INSERT_INTO_JSON_OBJECT(val, doc, prev_id, b.prev_id);
-  INSERT_INTO_JSON_OBJECT(val, doc, nonce, b.nonce);
-  INSERT_INTO_JSON_OBJECT(val, doc, miner_tx, b.miner_tx);
-  INSERT_INTO_JSON_OBJECT(val, doc, tx_hashes, b.tx_hashes);
+  dest.EndObject();
 }
 
 
@@ -275,35 +285,34 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::block& b)
   GET_FROM_JSON_OBJECT(val, b.tx_hashes, tx_hashes);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txin_v& txin, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txin_v& txin)
 {
-  val.SetObject();
-
+  dest.StartObject();
   struct add_input
   {
     using result_type = void;
 
-    rapidjson::Document& doc;
-    rapidjson::Value& val;
+    rapidjson::Writer<rapidjson::StringBuffer>& dest;
 
     void operator()(cryptonote::txin_to_key const& input) const
     {
-      INSERT_INTO_JSON_OBJECT(val, doc, to_key, input);
+      INSERT_INTO_JSON_OBJECT(dest, to_key, input);
     }
     void operator()(cryptonote::txin_gen const& input) const
     {
-      INSERT_INTO_JSON_OBJECT(val, doc, gen, input);
+      INSERT_INTO_JSON_OBJECT(dest, gen, input);
     }
     void operator()(cryptonote::txin_to_script const& input) const
     {
-      INSERT_INTO_JSON_OBJECT(val, doc, to_script, input);
+      INSERT_INTO_JSON_OBJECT(dest, to_script, input);
     }
     void operator()(cryptonote::txin_to_scripthash const& input) const
     {
-      INSERT_INTO_JSON_OBJECT(val, doc, to_scripthash, input);
+      INSERT_INTO_JSON_OBJECT(dest, to_scripthash, input);
     }
   };
-  boost::apply_visitor(add_input{doc, val}, txin);
+  boost::apply_visitor(add_input{dest}, txin);
+  dest.EndObject();
 }
 
 
@@ -348,13 +357,14 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::txin_v& txin)
   }
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txin_gen& txin, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txin_gen& txin)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, height, txin.height);
-}
+  INSERT_INTO_JSON_OBJECT(dest, height, txin.height);
 
+  dest.EndObject();
+}
 
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txin_gen& txin)
 {
@@ -366,13 +376,15 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::txin_gen& txin)
   GET_FROM_JSON_OBJECT(val, txin.height, height);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txin_to_script& txin, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txin_to_script& txin)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, prev, txin.prev);
+  INSERT_INTO_JSON_OBJECT(dest, prevout, txin.prevout);
+  INSERT_INTO_JSON_OBJECT(dest, sigset, txin.sigset);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, prev, txin.prev);
-  INSERT_INTO_JSON_OBJECT(val, doc, prevout, txin.prevout);
-  INSERT_INTO_JSON_OBJECT(val, doc, sigset, txin.sigset);
+  dest.EndObject();
 }
 
 
@@ -388,14 +400,17 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::txin_to_script& txin
   GET_FROM_JSON_OBJECT(val, txin.sigset, sigset);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txin_to_scripthash& txin, rapidjson::Value& val)
+
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txin_to_scripthash& txin)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, prev, txin.prev);
+  INSERT_INTO_JSON_OBJECT(dest, prevout, txin.prevout);
+  INSERT_INTO_JSON_OBJECT(dest, script, txin.script);
+  INSERT_INTO_JSON_OBJECT(dest, sigset, txin.sigset);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, prev, txin.prev);
-  INSERT_INTO_JSON_OBJECT(val, doc, prevout, txin.prevout);
-  INSERT_INTO_JSON_OBJECT(val, doc, script, txin.script);
-  INSERT_INTO_JSON_OBJECT(val, doc, sigset, txin.sigset);
+  dest.EndObject();
 }
 
 
@@ -412,15 +427,16 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::txin_to_scripthash&
   GET_FROM_JSON_OBJECT(val, txin.sigset, sigset);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txin_to_key& txin, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txin_to_key& txin)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, amount, txin.amount);
-  INSERT_INTO_JSON_OBJECT(val, doc, key_offsets, txin.key_offsets);
-  INSERT_INTO_JSON_OBJECT(val, doc, key_image, txin.k_image);
-}
+  INSERT_INTO_JSON_OBJECT(dest, amount, txin.amount);
+  INSERT_INTO_JSON_OBJECT(dest, key_offsets, txin.key_offsets);
+  INSERT_INTO_JSON_OBJECT(dest, key_image, txin.k_image);
 
+  dest.EndObject();
+}
 
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txin_to_key& txin)
 {
@@ -434,14 +450,16 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::txin_to_key& txin)
   GET_FROM_JSON_OBJECT(val, txin.k_image, key_image);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txout_to_script& txout, rapidjson::Value& val)
+
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txout_to_script& txout)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, keys, txout.keys);
-  INSERT_INTO_JSON_OBJECT(val, doc, script, txout.script);
-}
+  INSERT_INTO_JSON_OBJECT(dest, keys, txout.keys);
+  INSERT_INTO_JSON_OBJECT(dest, script, txout.script);
 
+  dest.EndObject();
+}
 
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txout_to_script& txout)
 {
@@ -454,13 +472,15 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::txout_to_script& txo
   GET_FROM_JSON_OBJECT(val, txout.script, script);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txout_to_scripthash& txout, rapidjson::Value& val)
+
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txout_to_scripthash& txout)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, hash, txout.hash);
-}
+  INSERT_INTO_JSON_OBJECT(dest, hash, txout.hash);
 
+  dest.EndObject();
+}
 
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txout_to_scripthash& txout)
 {
@@ -472,13 +492,15 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::txout_to_scripthash&
   GET_FROM_JSON_OBJECT(val, txout.hash, hash);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txout_to_key& txout, rapidjson::Value& val)
+
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txout_to_key& txout)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, key, txout.key);
-}
+  INSERT_INTO_JSON_OBJECT(dest, key, txout.key);
 
+  dest.EndObject();
+}
 
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txout_to_key& txout)
 {
@@ -490,33 +512,32 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::txout_to_key& txout)
   GET_FROM_JSON_OBJECT(val, txout.key, key);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::tx_out& txout, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::tx_out& txout)
 {
-  val.SetObject();
-
-  INSERT_INTO_JSON_OBJECT(val, doc, amount, txout.amount);
+  dest.StartObject();
+  INSERT_INTO_JSON_OBJECT(dest, amount, txout.amount);
 
   struct add_output
   {
     using result_type = void;
 
-    rapidjson::Document& doc;
-    rapidjson::Value& val;
+    rapidjson::Writer<rapidjson::StringBuffer>& dest;
 
     void operator()(cryptonote::txout_to_key const& output) const
     {
-      INSERT_INTO_JSON_OBJECT(val, doc, to_key, output);
+      INSERT_INTO_JSON_OBJECT(dest, to_key, output);
     }
     void operator()(cryptonote::txout_to_script const& output) const
     {
-      INSERT_INTO_JSON_OBJECT(val, doc, to_script, output);
+      INSERT_INTO_JSON_OBJECT(dest, to_script, output);
     }
     void operator()(cryptonote::txout_to_scripthash const& output) const
     {
-      INSERT_INTO_JSON_OBJECT(val, doc, to_scripthash, output);
+      INSERT_INTO_JSON_OBJECT(dest, to_scripthash, output);
     }
   };
-  boost::apply_visitor(add_output{doc, val}, txout.target);
+  boost::apply_visitor(add_output{dest}, txout.target);
+   dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, cryptonote::tx_out& txout)
@@ -559,37 +580,39 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::tx_out& txout)
   }
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::connection_info& info, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::connection_info& info)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, incoming, info.incoming);
+  INSERT_INTO_JSON_OBJECT(dest, localhost, info.localhost);
+  INSERT_INTO_JSON_OBJECT(dest, local_ip, info.local_ip);
+  INSERT_INTO_JSON_OBJECT(dest, address_type, info.address_type);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, incoming, info.incoming);
-  INSERT_INTO_JSON_OBJECT(val, doc, localhost, info.localhost);
-  INSERT_INTO_JSON_OBJECT(val, doc, local_ip, info.local_ip);
-  INSERT_INTO_JSON_OBJECT(val, doc, address_type, info.address_type);
+  INSERT_INTO_JSON_OBJECT(dest, ip, info.ip);
+  INSERT_INTO_JSON_OBJECT(dest, port, info.port);
+  INSERT_INTO_JSON_OBJECT(dest, rpc_port, info.rpc_port);
+  INSERT_INTO_JSON_OBJECT(dest, rpc_credits_per_hash, info.rpc_credits_per_hash);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, ip, info.ip);
-  INSERT_INTO_JSON_OBJECT(val, doc, port, info.port);
-  INSERT_INTO_JSON_OBJECT(val, doc, rpc_port, info.rpc_port);
-  INSERT_INTO_JSON_OBJECT(val, doc, rpc_credits_per_hash, info.rpc_credits_per_hash);
+  INSERT_INTO_JSON_OBJECT(dest, peer_id, info.peer_id);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, peer_id, info.peer_id);
+  INSERT_INTO_JSON_OBJECT(dest, recv_count, info.recv_count);
+  INSERT_INTO_JSON_OBJECT(dest, recv_idle_time, info.recv_idle_time);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, recv_count, info.recv_count);
-  INSERT_INTO_JSON_OBJECT(val, doc, recv_idle_time, info.recv_idle_time);
+  INSERT_INTO_JSON_OBJECT(dest, send_count, info.send_count);
+  INSERT_INTO_JSON_OBJECT(dest, send_idle_time, info.send_idle_time);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, send_count, info.send_count);
-  INSERT_INTO_JSON_OBJECT(val, doc, send_idle_time, info.send_idle_time);
+  INSERT_INTO_JSON_OBJECT(dest, state, info.state);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, state, info.state);
+  INSERT_INTO_JSON_OBJECT(dest, live_time, info.live_time);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, live_time, info.live_time);
+  INSERT_INTO_JSON_OBJECT(dest, avg_download, info.avg_download);
+  INSERT_INTO_JSON_OBJECT(dest, current_download, info.current_download);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, avg_download, info.avg_download);
-  INSERT_INTO_JSON_OBJECT(val, doc, current_download, info.current_download);
+  INSERT_INTO_JSON_OBJECT(dest, avg_upload, info.avg_upload);
+  INSERT_INTO_JSON_OBJECT(dest, current_upload, info.current_upload);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, avg_upload, info.avg_upload);
-  INSERT_INTO_JSON_OBJECT(val, doc, current_upload, info.current_upload);
+  dest.EndObject();
 }
 
 
@@ -629,12 +652,14 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::connection_info& inf
   GET_FROM_JSON_OBJECT(val, info.current_upload, current_upload);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::tx_blob_entry& tx, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::tx_blob_entry& tx)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, blob, tx.blob);
+  INSERT_INTO_JSON_OBJECT(dest, prunable_hash, tx.prunable_hash);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, blob, tx.blob);
-  INSERT_INTO_JSON_OBJECT(val, doc, prunable_hash, tx.prunable_hash);
+  dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, cryptonote::tx_blob_entry& tx)
@@ -648,12 +673,14 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::tx_blob_entry& tx)
   GET_FROM_JSON_OBJECT(val, tx.prunable_hash, prunable_hash);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::block_complete_entry& blk, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::block_complete_entry& blk)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, block, blk.block);
-  INSERT_INTO_JSON_OBJECT(val, doc, transactions, blk.txs);
+  INSERT_INTO_JSON_OBJECT(dest, block, blk.block);
+  INSERT_INTO_JSON_OBJECT(dest, transactions, blk.txs);
+
+  dest.EndObject();
 }
 
 
@@ -668,12 +695,14 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::block_complete_entry
   GET_FROM_JSON_OBJECT(val, blk.txs, transactions);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::block_with_transactions& blk, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::block_with_transactions& blk)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, block, blk.block);
+  INSERT_INTO_JSON_OBJECT(dest, transactions, blk.transactions);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, block, blk.block);
-  INSERT_INTO_JSON_OBJECT(val, doc, transactions, blk.transactions);
+  dest.EndObject();
 }
 
 
@@ -688,13 +717,15 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::block_with_tran
   GET_FROM_JSON_OBJECT(val, blk.transactions, transactions);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::transaction_info& tx_info, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::transaction_info& tx_info)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, height, tx_info.height);
+  INSERT_INTO_JSON_OBJECT(dest, in_pool, tx_info.in_pool);
+  INSERT_INTO_JSON_OBJECT(dest, transaction, tx_info.transaction);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, height, tx_info.height);
-  INSERT_INTO_JSON_OBJECT(val, doc, in_pool, tx_info.in_pool);
-  INSERT_INTO_JSON_OBJECT(val, doc, transaction, tx_info.transaction);
+  dest.EndObject();
 }
 
 
@@ -710,12 +741,14 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::transaction_inf
   GET_FROM_JSON_OBJECT(val, tx_info.transaction, transaction);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::output_key_and_amount_index& out, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::output_key_and_amount_index& out)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, amount_index, out.amount_index);
-  INSERT_INTO_JSON_OBJECT(val, doc, key, out.key);
+  INSERT_INTO_JSON_OBJECT(dest, amount_index, out.amount_index);
+  INSERT_INTO_JSON_OBJECT(dest, key, out.key);
+
+  dest.EndObject();
 }
 
 
@@ -730,12 +763,14 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::output_key_and_
   GET_FROM_JSON_OBJECT(val, out.key, key);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::amount_with_random_outputs& out, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::amount_with_random_outputs& out)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, amount, out.amount);
+  INSERT_INTO_JSON_OBJECT(dest, outputs, out.outputs);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, amount, out.amount);
-  INSERT_INTO_JSON_OBJECT(val, doc, outputs, out.outputs);
+  dest.EndObject();
 }
 
 
@@ -750,17 +785,19 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::amount_with_ran
   GET_FROM_JSON_OBJECT(val, out.outputs, outputs);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::peer& peer, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::peer& peer)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, id, peer.id);
+  INSERT_INTO_JSON_OBJECT(dest, ip, peer.ip);
+  INSERT_INTO_JSON_OBJECT(dest, port, peer.port);
+  INSERT_INTO_JSON_OBJECT(dest, rpc_port, peer.rpc_port);
+  INSERT_INTO_JSON_OBJECT(dest, rpc_credits_per_hash, peer.rpc_credits_per_hash);
+  INSERT_INTO_JSON_OBJECT(dest, last_seen, peer.last_seen);
+  INSERT_INTO_JSON_OBJECT(dest, pruning_seed, peer.pruning_seed);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, id, peer.id);
-  INSERT_INTO_JSON_OBJECT(val, doc, ip, peer.ip);
-  INSERT_INTO_JSON_OBJECT(val, doc, port, peer.port);
-  INSERT_INTO_JSON_OBJECT(val, doc, rpc_port, peer.rpc_port);
-  INSERT_INTO_JSON_OBJECT(val, doc, rpc_credits_per_hash, peer.rpc_credits_per_hash);
-  INSERT_INTO_JSON_OBJECT(val, doc, last_seen, peer.last_seen);
-  INSERT_INTO_JSON_OBJECT(val, doc, pruning_seed, peer.pruning_seed);
+  dest.EndObject();
 }
 
 
@@ -780,25 +817,27 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::peer& peer)
   GET_FROM_JSON_OBJECT(val, peer.pruning_seed, pruning_seed);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::tx_in_pool& tx, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::tx_in_pool& tx)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, tx, tx.tx);
-  INSERT_INTO_JSON_OBJECT(val, doc, tx_hash, tx.tx_hash);
-  INSERT_INTO_JSON_OBJECT(val, doc, blob_size, tx.blob_size);
-  INSERT_INTO_JSON_OBJECT(val, doc, weight, tx.weight);
-  INSERT_INTO_JSON_OBJECT(val, doc, fee, tx.fee);
-  INSERT_INTO_JSON_OBJECT(val, doc, max_used_block_hash, tx.max_used_block_hash);
-  INSERT_INTO_JSON_OBJECT(val, doc, max_used_block_height, tx.max_used_block_height);
-  INSERT_INTO_JSON_OBJECT(val, doc, kept_by_block, tx.kept_by_block);
-  INSERT_INTO_JSON_OBJECT(val, doc, last_failed_block_hash, tx.last_failed_block_hash);
-  INSERT_INTO_JSON_OBJECT(val, doc, last_failed_block_height, tx.last_failed_block_height);
-  INSERT_INTO_JSON_OBJECT(val, doc, receive_time, tx.receive_time);
-  INSERT_INTO_JSON_OBJECT(val, doc, last_relayed_time, tx.last_relayed_time);
-  INSERT_INTO_JSON_OBJECT(val, doc, relayed, tx.relayed);
-  INSERT_INTO_JSON_OBJECT(val, doc, do_not_relay, tx.do_not_relay);
-  INSERT_INTO_JSON_OBJECT(val, doc, double_spend_seen, tx.double_spend_seen);
+  INSERT_INTO_JSON_OBJECT(dest, tx, tx.tx);
+  INSERT_INTO_JSON_OBJECT(dest, tx_hash, tx.tx_hash);
+  INSERT_INTO_JSON_OBJECT(dest, blob_size, tx.blob_size);
+  INSERT_INTO_JSON_OBJECT(dest, weight, tx.weight);
+  INSERT_INTO_JSON_OBJECT(dest, fee, tx.fee);
+  INSERT_INTO_JSON_OBJECT(dest, max_used_block_hash, tx.max_used_block_hash);
+  INSERT_INTO_JSON_OBJECT(dest, max_used_block_height, tx.max_used_block_height);
+  INSERT_INTO_JSON_OBJECT(dest, kept_by_block, tx.kept_by_block);
+  INSERT_INTO_JSON_OBJECT(dest, last_failed_block_hash, tx.last_failed_block_hash);
+  INSERT_INTO_JSON_OBJECT(dest, last_failed_block_height, tx.last_failed_block_height);
+  INSERT_INTO_JSON_OBJECT(dest, receive_time, tx.receive_time);
+  INSERT_INTO_JSON_OBJECT(dest, last_relayed_time, tx.last_relayed_time);
+  INSERT_INTO_JSON_OBJECT(dest, relayed, tx.relayed);
+  INSERT_INTO_JSON_OBJECT(dest, do_not_relay, tx.do_not_relay);
+  INSERT_INTO_JSON_OBJECT(dest, double_spend_seen, tx.double_spend_seen);
+
+  dest.EndObject();
 }
 
 
@@ -825,18 +864,20 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::tx_in_pool& tx)
   GET_FROM_JSON_OBJECT(val, tx.double_spend_seen, double_spend_seen);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::hard_fork_info& info, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::hard_fork_info& info)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, version, info.version);
+  INSERT_INTO_JSON_OBJECT(dest, enabled, info.enabled);
+  INSERT_INTO_JSON_OBJECT(dest, window, info.window);
+  INSERT_INTO_JSON_OBJECT(dest, votes, info.votes);
+  INSERT_INTO_JSON_OBJECT(dest, threshold, info.threshold);
+  INSERT_INTO_JSON_OBJECT(dest, voting, info.voting);
+  INSERT_INTO_JSON_OBJECT(dest, state, info.state);
+  INSERT_INTO_JSON_OBJECT(dest, earliest_height, info.earliest_height);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, version, info.version);
-  INSERT_INTO_JSON_OBJECT(val, doc, enabled, info.enabled);
-  INSERT_INTO_JSON_OBJECT(val, doc, window, info.window);
-  INSERT_INTO_JSON_OBJECT(val, doc, votes, info.votes);
-  INSERT_INTO_JSON_OBJECT(val, doc, threshold, info.threshold);
-  INSERT_INTO_JSON_OBJECT(val, doc, voting, info.voting);
-  INSERT_INTO_JSON_OBJECT(val, doc, state, info.state);
-  INSERT_INTO_JSON_OBJECT(val, doc, earliest_height, info.earliest_height);
+  dest.EndObject();
 }
 
 
@@ -857,14 +898,16 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::hard_fork_info&
   GET_FROM_JSON_OBJECT(val, info.earliest_height, earliest_height);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::output_amount_count& out, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::output_amount_count& out)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, amount, out.amount);
-  INSERT_INTO_JSON_OBJECT(val, doc, total_count, out.total_count);
-  INSERT_INTO_JSON_OBJECT(val, doc, unlocked_count, out.unlocked_count);
-  INSERT_INTO_JSON_OBJECT(val, doc, recent_count, out.recent_count);
+  INSERT_INTO_JSON_OBJECT(dest, amount, out.amount);
+  INSERT_INTO_JSON_OBJECT(dest, total_count, out.total_count);
+  INSERT_INTO_JSON_OBJECT(dest, unlocked_count, out.unlocked_count);
+  INSERT_INTO_JSON_OBJECT(dest, recent_count, out.recent_count);
+
+  dest.EndObject();
 }
 
 
@@ -881,12 +924,14 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::output_amount_c
   GET_FROM_JSON_OBJECT(val, out.recent_count, recent_count);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::output_amount_and_index& out, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::output_amount_and_index& out)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, amount, out.amount);
+  INSERT_INTO_JSON_OBJECT(dest, index, out.index);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, amount, out.amount);
-  INSERT_INTO_JSON_OBJECT(val, doc, index, out.index);
+  dest.EndObject();
 }
 
 
@@ -901,13 +946,15 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::output_amount_a
   GET_FROM_JSON_OBJECT(val, out.index, index);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::output_key_mask_unlocked& out, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::output_key_mask_unlocked& out)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, key, out.key);
+  INSERT_INTO_JSON_OBJECT(dest, mask, out.mask);
+  INSERT_INTO_JSON_OBJECT(dest, unlocked, out.unlocked);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, key, out.key);
-  INSERT_INTO_JSON_OBJECT(val, doc, mask, out.mask);
-  INSERT_INTO_JSON_OBJECT(val, doc, unlocked, out.unlocked);
+  dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::output_key_mask_unlocked& out)
@@ -922,13 +969,15 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::output_key_mask
   GET_FROM_JSON_OBJECT(val, out.unlocked, unlocked);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::error& err, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::error& err)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, code, err.code);
-  INSERT_INTO_JSON_OBJECT(val, doc, error_str, err.error_str);
-  INSERT_INTO_JSON_OBJECT(val, doc, message, err.message);
+  INSERT_INTO_JSON_OBJECT(dest, code, err.code);
+  INSERT_INTO_JSON_OBJECT(dest, error_str, err.error_str);
+  INSERT_INTO_JSON_OBJECT(dest, message, err.message);
+
+  dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::error& error)
@@ -943,20 +992,22 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::error& error)
   GET_FROM_JSON_OBJECT(val, error.message, message);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::BlockHeaderResponse& response, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::BlockHeaderResponse& response)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, major_version, response.major_version);
+  INSERT_INTO_JSON_OBJECT(dest, minor_version, response.minor_version);
+  INSERT_INTO_JSON_OBJECT(dest, timestamp, response.timestamp);
+  INSERT_INTO_JSON_OBJECT(dest, prev_id, response.prev_id);
+  INSERT_INTO_JSON_OBJECT(dest, nonce, response.nonce);
+  INSERT_INTO_JSON_OBJECT(dest, height, response.height);
+  INSERT_INTO_JSON_OBJECT(dest, depth, response.depth);
+  INSERT_INTO_JSON_OBJECT(dest, hash, response.hash);
+  INSERT_INTO_JSON_OBJECT(dest, difficulty, response.difficulty);
+  INSERT_INTO_JSON_OBJECT(dest, reward, response.reward);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, major_version, response.major_version);
-  INSERT_INTO_JSON_OBJECT(val, doc, minor_version, response.minor_version);
-  INSERT_INTO_JSON_OBJECT(val, doc, timestamp, response.timestamp);
-  INSERT_INTO_JSON_OBJECT(val, doc, prev_id, response.prev_id);
-  INSERT_INTO_JSON_OBJECT(val, doc, nonce, response.nonce);
-  INSERT_INTO_JSON_OBJECT(val, doc, height, response.height);
-  INSERT_INTO_JSON_OBJECT(val, doc, depth, response.depth);
-  INSERT_INTO_JSON_OBJECT(val, doc, hash, response.hash);
-  INSERT_INTO_JSON_OBJECT(val, doc, difficulty, response.difficulty);
-  INSERT_INTO_JSON_OBJECT(val, doc, reward, response.reward);
+  dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::BlockHeaderResponse& response)
@@ -978,34 +1029,36 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::BlockHeaderResp
   GET_FROM_JSON_OBJECT(val, response.reward, reward);
 }
 
-void toJsonValue(rapidjson::Document& doc, const rct::rctSig& sig, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rct::rctSig& sig)
 {
   using boost::adaptors::transform;
 
-  val.SetObject();
+  dest.StartObject();
 
   const auto just_mask = [] (rct::ctkey const& key) -> rct::key const&
   {
     return key.mask;
   };
 
-  INSERT_INTO_JSON_OBJECT(val, doc, type, sig.type);
-  INSERT_INTO_JSON_OBJECT(val, doc, encrypted, sig.ecdhInfo);
-  INSERT_INTO_JSON_OBJECT(val, doc, commitments, transform(sig.outPk, just_mask));
-  INSERT_INTO_JSON_OBJECT(val, doc, fee, sig.txnFee);
+  INSERT_INTO_JSON_OBJECT(dest, type, sig.type);
+  INSERT_INTO_JSON_OBJECT(dest, encrypted, sig.ecdhInfo);
+  INSERT_INTO_JSON_OBJECT(dest, commitments, transform(sig.outPk, just_mask));
+  INSERT_INTO_JSON_OBJECT(dest, fee, sig.txnFee);
 
   // prunable
   {
-    rapidjson::Value prunable;
-    prunable.SetObject();
+    dest.Key("prunable");
+    dest.StartObject();
 
-    INSERT_INTO_JSON_OBJECT(prunable, doc, range_proofs, sig.p.rangeSigs);
-    INSERT_INTO_JSON_OBJECT(prunable, doc, bulletproofs, sig.p.bulletproofs);
-    INSERT_INTO_JSON_OBJECT(prunable, doc, mlsags, sig.p.MGs);
-    INSERT_INTO_JSON_OBJECT(prunable, doc, pseudo_outs, sig.get_pseudo_outs());
+    INSERT_INTO_JSON_OBJECT(dest, range_proofs, sig.p.rangeSigs);
+    INSERT_INTO_JSON_OBJECT(dest, bulletproofs, sig.p.bulletproofs);
+    INSERT_INTO_JSON_OBJECT(dest, mlsags, sig.p.MGs);
+    INSERT_INTO_JSON_OBJECT(dest, pseudo_outs, sig.get_pseudo_outs());
 
-    val.AddMember("prunable", prunable, doc.GetAllocator());
+    dest.EndObject();
   }
+
+  dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, rct::rctSig& sig)
@@ -1046,12 +1099,12 @@ void fromJsonValue(const rapidjson::Value& val, rct::rctSig& sig)
   }
 }
 
-void toJsonValue(rapidjson::Document& doc, const rct::ecdhTuple& tuple, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rct::ecdhTuple& tuple)
 {
-  val.SetObject();
-
-  INSERT_INTO_JSON_OBJECT(val, doc, mask, tuple.mask);
-  INSERT_INTO_JSON_OBJECT(val, doc, amount, tuple.amount);
+  dest.StartObject();
+  INSERT_INTO_JSON_OBJECT(dest, mask, tuple.mask);
+  INSERT_INTO_JSON_OBJECT(dest, amount, tuple.amount);
+  dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, rct::ecdhTuple& tuple)
@@ -1065,14 +1118,14 @@ void fromJsonValue(const rapidjson::Value& val, rct::ecdhTuple& tuple)
   GET_FROM_JSON_OBJECT(val, tuple.amount, amount);
 }
 
-void toJsonValue(rapidjson::Document& doc, const rct::rangeSig& sig, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rct::rangeSig& sig)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, asig, sig.asig);
+  INSERT_INTO_JSON_OBJECT(dest, asig, sig.asig);
+  INSERT_INTO_JSON_OBJECT(dest, Ci, epee::span<const rct::key>{sig.Ci});
 
-  std::vector<rct::key> keyVector(sig.Ci, std::end(sig.Ci));
-  INSERT_INTO_JSON_OBJECT(val, doc, Ci, keyVector);
+  dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, rct::rangeSig& sig)
@@ -1102,22 +1155,24 @@ void fromJsonValue(const rapidjson::Value& val, rct::rangeSig& sig)
   }
 }
 
-void toJsonValue(rapidjson::Document& doc, const rct::Bulletproof& p, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rct::Bulletproof& p)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, V, p.V);
+  INSERT_INTO_JSON_OBJECT(dest, A, p.A);
+  INSERT_INTO_JSON_OBJECT(dest, S, p.S);
+  INSERT_INTO_JSON_OBJECT(dest, T1, p.T1);
+  INSERT_INTO_JSON_OBJECT(dest, T2, p.T2);
+  INSERT_INTO_JSON_OBJECT(dest, taux, p.taux);
+  INSERT_INTO_JSON_OBJECT(dest, mu, p.mu);
+  INSERT_INTO_JSON_OBJECT(dest, L, p.L);
+  INSERT_INTO_JSON_OBJECT(dest, R, p.R);
+  INSERT_INTO_JSON_OBJECT(dest, a, p.a);
+  INSERT_INTO_JSON_OBJECT(dest, b, p.b);
+  INSERT_INTO_JSON_OBJECT(dest, t, p.t);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, V, p.V);
-  INSERT_INTO_JSON_OBJECT(val, doc, A, p.A);
-  INSERT_INTO_JSON_OBJECT(val, doc, S, p.S);
-  INSERT_INTO_JSON_OBJECT(val, doc, T1, p.T1);
-  INSERT_INTO_JSON_OBJECT(val, doc, T2, p.T2);
-  INSERT_INTO_JSON_OBJECT(val, doc, taux, p.taux);
-  INSERT_INTO_JSON_OBJECT(val, doc, mu, p.mu);
-  INSERT_INTO_JSON_OBJECT(val, doc, L, p.L);
-  INSERT_INTO_JSON_OBJECT(val, doc, R, p.R);
-  INSERT_INTO_JSON_OBJECT(val, doc, a, p.a);
-  INSERT_INTO_JSON_OBJECT(val, doc, b, p.b);
-  INSERT_INTO_JSON_OBJECT(val, doc, t, p.t);
+  dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, rct::Bulletproof& p)
@@ -1141,17 +1196,15 @@ void fromJsonValue(const rapidjson::Value& val, rct::Bulletproof& p)
   GET_FROM_JSON_OBJECT(val, p.t, t);
 }
 
-void toJsonValue(rapidjson::Document& doc, const rct::boroSig& sig, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rct::boroSig& sig)
 {
-  val.SetObject();
-
-  std::vector<rct::key> keyVector(sig.s0, std::end(sig.s0));
-  INSERT_INTO_JSON_OBJECT(val, doc, s0, keyVector);
+  dest.StartObject();
 
-  keyVector.assign(sig.s1, std::end(sig.s1));
-  INSERT_INTO_JSON_OBJECT(val, doc, s1, keyVector);
+  INSERT_INTO_JSON_OBJECT(dest, s0, epee::span<const rct::key>{sig.s0});
+  INSERT_INTO_JSON_OBJECT(dest, s1, epee::span<const rct::key>{sig.s1});
+  INSERT_INTO_JSON_OBJECT(dest, ee, sig.ee);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, ee, sig.ee);
+  dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, rct::boroSig& sig)
@@ -1188,12 +1241,14 @@ void fromJsonValue(const rapidjson::Value& val, rct::boroSig& sig)
   GET_FROM_JSON_OBJECT(val, sig.ee, ee);
 }
 
-void toJsonValue(rapidjson::Document& doc, const rct::mgSig& sig, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rct::mgSig& sig)
 {
-  val.SetObject();
+  dest.StartObject();
 
-  INSERT_INTO_JSON_OBJECT(val, doc, ss, sig.ss);
-  INSERT_INTO_JSON_OBJECT(val, doc, cc, sig.cc);
+  INSERT_INTO_JSON_OBJECT(dest, ss, sig.ss);
+  INSERT_INTO_JSON_OBJECT(dest, cc, sig.cc);
+
+  dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, rct::mgSig& sig)
@@ -1207,32 +1262,34 @@ void fromJsonValue(const rapidjson::Value& val, rct::mgSig& sig)
   GET_FROM_JSON_OBJECT(val, sig.cc, cc);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::DaemonInfo& info, rapidjson::Value& val)
-{
-  val.SetObject();
-
-  INSERT_INTO_JSON_OBJECT(val, doc, height, info.height);
-  INSERT_INTO_JSON_OBJECT(val, doc, target_height, info.target_height);
-  INSERT_INTO_JSON_OBJECT(val, doc, difficulty, info.difficulty);
-  INSERT_INTO_JSON_OBJECT(val, doc, target, info.target);
-  INSERT_INTO_JSON_OBJECT(val, doc, tx_count, info.tx_count);
-  INSERT_INTO_JSON_OBJECT(val, doc, tx_pool_size, info.tx_pool_size);
-  INSERT_INTO_JSON_OBJECT(val, doc, alt_blocks_count, info.alt_blocks_count);
-  INSERT_INTO_JSON_OBJECT(val, doc, outgoing_connections_count, info.outgoing_connections_count);
-  INSERT_INTO_JSON_OBJECT(val, doc, incoming_connections_count, info.incoming_connections_count);
-  INSERT_INTO_JSON_OBJECT(val, doc, white_peerlist_size, info.white_peerlist_size);
-  INSERT_INTO_JSON_OBJECT(val, doc, grey_peerlist_size, info.grey_peerlist_size);
-  INSERT_INTO_JSON_OBJECT(val, doc, mainnet, info.mainnet);
-  INSERT_INTO_JSON_OBJECT(val, doc, testnet, info.testnet);
-  INSERT_INTO_JSON_OBJECT(val, doc, stagenet, info.stagenet);
-  INSERT_INTO_JSON_OBJECT(val, doc, nettype, info.nettype);
-  INSERT_INTO_JSON_OBJECT(val, doc, top_block_hash, info.top_block_hash);
-  INSERT_INTO_JSON_OBJECT(val, doc, cumulative_difficulty, info.cumulative_difficulty);
-  INSERT_INTO_JSON_OBJECT(val, doc, block_size_limit, info.block_size_limit);
-  INSERT_INTO_JSON_OBJECT(val, doc, block_weight_limit, info.block_weight_limit);
-  INSERT_INTO_JSON_OBJECT(val, doc, block_size_median, info.block_size_median);
-  INSERT_INTO_JSON_OBJECT(val, doc, block_weight_median, info.block_weight_median);
-  INSERT_INTO_JSON_OBJECT(val, doc, start_time, info.start_time);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::DaemonInfo& info)
+{
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, height, info.height);
+  INSERT_INTO_JSON_OBJECT(dest, target_height, info.target_height);
+  INSERT_INTO_JSON_OBJECT(dest, difficulty, info.difficulty);
+  INSERT_INTO_JSON_OBJECT(dest, target, info.target);
+  INSERT_INTO_JSON_OBJECT(dest, tx_count, info.tx_count);
+  INSERT_INTO_JSON_OBJECT(dest, tx_pool_size, info.tx_pool_size);
+  INSERT_INTO_JSON_OBJECT(dest, alt_blocks_count, info.alt_blocks_count);
+  INSERT_INTO_JSON_OBJECT(dest, outgoing_connections_count, info.outgoing_connections_count);
+  INSERT_INTO_JSON_OBJECT(dest, incoming_connections_count, info.incoming_connections_count);
+  INSERT_INTO_JSON_OBJECT(dest, white_peerlist_size, info.white_peerlist_size);
+  INSERT_INTO_JSON_OBJECT(dest, grey_peerlist_size, info.grey_peerlist_size);
+  INSERT_INTO_JSON_OBJECT(dest, mainnet, info.mainnet);
+  INSERT_INTO_JSON_OBJECT(dest, testnet, info.testnet);
+  INSERT_INTO_JSON_OBJECT(dest, stagenet, info.stagenet);
+  INSERT_INTO_JSON_OBJECT(dest, nettype, info.nettype);
+  INSERT_INTO_JSON_OBJECT(dest, top_block_hash, info.top_block_hash);
+  INSERT_INTO_JSON_OBJECT(dest, cumulative_difficulty, info.cumulative_difficulty);
+  INSERT_INTO_JSON_OBJECT(dest, block_size_limit, info.block_size_limit);
+  INSERT_INTO_JSON_OBJECT(dest, block_weight_limit, info.block_weight_limit);
+  INSERT_INTO_JSON_OBJECT(dest, block_size_median, info.block_size_median);
+  INSERT_INTO_JSON_OBJECT(dest, block_weight_median, info.block_weight_median);
+  INSERT_INTO_JSON_OBJECT(dest, start_time, info.start_time);
+
+  dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::DaemonInfo& info)
@@ -1266,14 +1323,16 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::DaemonInfo& inf
   GET_FROM_JSON_OBJECT(val, info.start_time, start_time);
 }
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::output_distribution& dist, rapidjson::Value& val)
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::output_distribution& dist)
 {
-  val.SetObject();
+  dest.StartObject();
+
+  INSERT_INTO_JSON_OBJECT(dest, distribution, dist.data.distribution);
+  INSERT_INTO_JSON_OBJECT(dest, amount, dist.amount);
+  INSERT_INTO_JSON_OBJECT(dest, start_height, dist.data.start_height);
+  INSERT_INTO_JSON_OBJECT(dest, base, dist.data.base);
 
-  INSERT_INTO_JSON_OBJECT(val, doc, distribution, dist.data.distribution);
-  INSERT_INTO_JSON_OBJECT(val, doc, amount, dist.amount);
-  INSERT_INTO_JSON_OBJECT(val, doc, start_height, dist.data.start_height);
-  INSERT_INTO_JSON_OBJECT(val, doc, base, dist.data.base);
+  dest.EndObject();
 }
 
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::output_distribution& dist)
diff --git a/src/serialization/json_object.h b/src/serialization/json_object.h
index 5ef75b863..d2c579589 100644
--- a/src/serialization/json_object.h
+++ b/src/serialization/json_object.h
@@ -28,8 +28,13 @@
 
 #pragma once
 
+#include <boost/utility/string_ref.hpp>
+#include <cstring>
+#include <rapidjson/document.h>
+#include <rapidjson/stringbuffer.h>
+#include <rapidjson/writer.h>
+
 #include "string_tools.h"
-#include "rapidjson/document.h"
 #include "cryptonote_basic/cryptonote_basic.h"
 #include "rpc/message_data_structs.h"
 #include "cryptonote_protocol/cryptonote_protocol_defs.h"
@@ -44,10 +49,9 @@
     } \
   } while (0);
 
-#define INSERT_INTO_JSON_OBJECT(jsonVal, doc, key, source) \
-    rapidjson::Value key##Val; \
-    cryptonote::json::toJsonValue(doc, source, key##Val); \
-    jsonVal.AddMember(#key, key##Val, doc.GetAllocator());
+#define INSERT_INTO_JSON_OBJECT(dest, key, source) \
+    dest.Key(#key, sizeof(#key) - 1); \
+    cryptonote::json::toJsonValue(dest, source);
 
 #define GET_FROM_JSON_OBJECT(source, dst, key) \
     OBJECT_HAS_MEMBER_OR_THROW(source, #key) \
@@ -114,16 +118,24 @@ inline constexpr bool is_to_hex()
   return std::is_pod<Type>() && !std::is_integral<Type>();
 }
 
+// POD to json key
+template <class Type>
+inline typename std::enable_if<is_to_hex<Type>()>::type toJsonKey(rapidjson::Writer<rapidjson::StringBuffer>& dest, const Type& pod)
+{
+  const auto hex = epee::to_hex::array(pod);
+  dest.Key(hex.data(), hex.size());
+}
 
 // POD to json value
 template <class Type>
-typename std::enable_if<is_to_hex<Type>()>::type toJsonValue(rapidjson::Document& doc, const Type& pod, rapidjson::Value& value)
+inline typename std::enable_if<is_to_hex<Type>()>::type toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const Type& pod)
 {
-  value = rapidjson::Value(epee::string_tools::pod_to_hex(pod).c_str(), doc.GetAllocator());
+  const auto hex = epee::to_hex::array(pod);
+  dest.String(hex.data(), hex.size());
 }
 
 template <class Type>
-typename std::enable_if<is_to_hex<Type>()>::type fromJsonValue(const rapidjson::Value& val, Type& t)
+inline typename std::enable_if<is_to_hex<Type>()>::type fromJsonValue(const rapidjson::Value& val, Type& t)
 {
   if (!val.IsString())
   {
@@ -139,10 +151,16 @@ typename std::enable_if<is_to_hex<Type>()>::type fromJsonValue(const rapidjson::
   }
 }
 
-void toJsonValue(rapidjson::Document& doc, const std::string& i, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rapidjson::Value& src);
+
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, boost::string_ref i);
+inline void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const std::string& i)
+{
+  toJsonValue(dest, boost::string_ref{i});
+}
 void fromJsonValue(const rapidjson::Value& val, std::string& str);
 
-void toJsonValue(rapidjson::Document& doc, bool i, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, bool i);
 void fromJsonValue(const rapidjson::Value& val, bool& b);
 
 // integers overloads for toJsonValue are not needed for standard promotions
@@ -157,144 +175,144 @@ void fromJsonValue(const rapidjson::Value& val, unsigned short& i);
 
 void fromJsonValue(const rapidjson::Value& val, short& i);
 
-void toJsonValue(rapidjson::Document& doc, const unsigned i, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const unsigned i);
 void fromJsonValue(const rapidjson::Value& val, unsigned& i);
 
-void toJsonValue(rapidjson::Document& doc, const int, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const int);
 void fromJsonValue(const rapidjson::Value& val, int& i);
 
 
-void toJsonValue(rapidjson::Document& doc, const unsigned long long i, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const unsigned long long i);
 void fromJsonValue(const rapidjson::Value& val, unsigned long long& i);
 
-void toJsonValue(rapidjson::Document& doc, const long long i, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const long long i);
 void fromJsonValue(const rapidjson::Value& val, long long& i);
 
-inline void toJsonValue(rapidjson::Document& doc, const unsigned long i, rapidjson::Value& val) {
-    toJsonValue(doc, static_cast<unsigned long long>(i), val);
+inline void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const unsigned long i) {
+    toJsonValue(dest, static_cast<unsigned long long>(i));
 }
 void fromJsonValue(const rapidjson::Value& val, unsigned long& i);
 
-inline void toJsonValue(rapidjson::Document& doc, const long i, rapidjson::Value& val) {
-    toJsonValue(doc, static_cast<long long>(i), val);
+inline void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const long i) {
+    toJsonValue(dest, static_cast<long long>(i));
 }
 void fromJsonValue(const rapidjson::Value& val, long& i);
 
 // end integers
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::transaction& tx, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::transaction& tx);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::transaction& tx);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::block& b, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::block& b);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::block& b);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txin_v& txin, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txin_v& txin);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txin_v& txin);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txin_gen& txin, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txin_gen& txin);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txin_gen& txin);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txin_to_script& txin, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txin_to_script& txin);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txin_to_script& txin);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txin_to_scripthash& txin, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txin_to_scripthash& txin);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txin_to_scripthash& txin);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txin_to_key& txin, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txin_to_key& txin);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txin_to_key& txin);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txout_target_v& txout, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txout_target_v& txout);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txout_target_v& txout);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txout_to_script& txout, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txout_to_script& txout);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txout_to_script& txout);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txout_to_scripthash& txout, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txout_to_scripthash& txout);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txout_to_scripthash& txout);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::txout_to_key& txout, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::txout_to_key& txout);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::txout_to_key& txout);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::tx_out& txout, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::tx_out& txout);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::tx_out& txout);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::connection_info& info, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::connection_info& info);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::connection_info& info);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::tx_blob_entry& tx, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::tx_blob_entry& tx);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::tx_blob_entry& tx);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::block_complete_entry& blk, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::block_complete_entry& blk);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::block_complete_entry& blk);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::block_with_transactions& blk, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::block_with_transactions& blk);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::block_with_transactions& blk);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::transaction_info& tx_info, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::transaction_info& tx_info);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::transaction_info& tx_info);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::output_key_and_amount_index& out, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::output_key_and_amount_index& out);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::output_key_and_amount_index& out);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::amount_with_random_outputs& out, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::amount_with_random_outputs& out);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::amount_with_random_outputs& out);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::peer& peer, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::peer& peer);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::peer& peer);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::tx_in_pool& tx, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::tx_in_pool& tx);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::tx_in_pool& tx);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::hard_fork_info& info, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::hard_fork_info& info);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::hard_fork_info& info);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::output_amount_count& out, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::output_amount_count& out);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::output_amount_count& out);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::output_amount_and_index& out, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::output_amount_and_index& out);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::output_amount_and_index& out);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::output_key_mask_unlocked& out, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::output_key_mask_unlocked& out);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::output_key_mask_unlocked& out);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::error& err, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::error& err);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::error& error);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::BlockHeaderResponse& response, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::BlockHeaderResponse& response);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::BlockHeaderResponse& response);
 
-void toJsonValue(rapidjson::Document& doc, const rct::rctSig& i, rapidjson::Value& val);
-void fromJsonValue(const rapidjson::Value& i, rct::rctSig& sig);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rct::rctSig& i);
+void fromJsonValue(const rapidjson::Value& val, rct::rctSig& sig);
 
-void toJsonValue(rapidjson::Document& doc, const rct::ecdhTuple& tuple, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rct::ecdhTuple& tuple);
 void fromJsonValue(const rapidjson::Value& val, rct::ecdhTuple& tuple);
 
-void toJsonValue(rapidjson::Document& doc, const rct::rangeSig& sig, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rct::rangeSig& sig);
 void fromJsonValue(const rapidjson::Value& val, rct::rangeSig& sig);
 
-void toJsonValue(rapidjson::Document& doc, const rct::Bulletproof& p, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rct::Bulletproof& p);
 void fromJsonValue(const rapidjson::Value& val, rct::Bulletproof& p);
 
-void toJsonValue(rapidjson::Document& doc, const rct::boroSig& sig, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rct::boroSig& sig);
 void fromJsonValue(const rapidjson::Value& val, rct::boroSig& sig);
 
-void toJsonValue(rapidjson::Document& doc, const rct::mgSig& sig, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const rct::mgSig& sig);
 void fromJsonValue(const rapidjson::Value& val, rct::mgSig& sig);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::DaemonInfo& info, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::DaemonInfo& info);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::DaemonInfo& info);
 
-void toJsonValue(rapidjson::Document& doc, const cryptonote::rpc::output_distribution& dist, rapidjson::Value& val);
+void toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const cryptonote::rpc::output_distribution& dist);
 void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::output_distribution& dist);
 
 template <typename Map>
-typename std::enable_if<sfinae::is_map_like<Map>::value, void>::type toJsonValue(rapidjson::Document& doc, const Map& map, rapidjson::Value& val);
+typename std::enable_if<sfinae::is_map_like<Map>::value, void>::type toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const Map& map);
 
 template <typename Map>
 typename std::enable_if<sfinae::is_map_like<Map>::value, void>::type fromJsonValue(const rapidjson::Value& val, Map& map);
 
 template <typename Vec>
-typename std::enable_if<sfinae::is_vector_like<Vec>::value, void>::type toJsonValue(rapidjson::Document& doc, const Vec &vec, rapidjson::Value& val);
+typename std::enable_if<sfinae::is_vector_like<Vec>::value, void>::type toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const Vec &vec);
 
 template <typename Vec>
 typename std::enable_if<sfinae::is_vector_like<Vec>::value, void>::type fromJsonValue(const rapidjson::Value& val, Vec& vec);
@@ -304,24 +322,22 @@ typename std::enable_if<sfinae::is_vector_like<Vec>::value, void>::type fromJson
 // unfortunately because of how templates work they have to be here.
 
 template <typename Map>
-typename std::enable_if<sfinae::is_map_like<Map>::value, void>::type toJsonValue(rapidjson::Document& doc, const Map& map, rapidjson::Value& val)
+inline typename std::enable_if<sfinae::is_map_like<Map>::value, void>::type toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const Map& map)
 {
-  val.SetObject();
-
-  auto& al = doc.GetAllocator();
+  using key_type = typename Map::key_type;
+  static_assert(std::is_same<std::string, key_type>() || is_to_hex<key_type>(), "invalid map key type");
 
+  dest.StartObject();
   for (const auto& i : map)
   {
-    rapidjson::Value k;
-    rapidjson::Value m;
-    toJsonValue(doc, i.first, k);
-    toJsonValue(doc, i.second, m);
-    val.AddMember(k, m, al);
+    toJsonKey(dest, i.first);
+    toJsonValue(dest, i.second);
   }
+  dest.EndObject();
 }
 
 template <typename Map>
-typename std::enable_if<sfinae::is_map_like<Map>::value, void>::type fromJsonValue(const rapidjson::Value& val, Map& map)
+inline typename std::enable_if<sfinae::is_map_like<Map>::value, void>::type fromJsonValue(const rapidjson::Value& val, Map& map)
 {
   if (!val.IsObject())
   {
@@ -342,20 +358,16 @@ typename std::enable_if<sfinae::is_map_like<Map>::value, void>::type fromJsonVal
 }
 
 template <typename Vec>
-typename std::enable_if<sfinae::is_vector_like<Vec>::value, void>::type toJsonValue(rapidjson::Document& doc, const Vec &vec, rapidjson::Value& val)
+inline typename std::enable_if<sfinae::is_vector_like<Vec>::value, void>::type toJsonValue(rapidjson::Writer<rapidjson::StringBuffer>& dest, const Vec &vec)
 {
-  val.SetArray();
-
+  dest.StartArray();
   for (const auto& t : vec)
-  {
-    rapidjson::Value v;
-    toJsonValue(doc, t, v);
-    val.PushBack(v, doc.GetAllocator());
-  }
+    toJsonValue(dest, t);
+  dest.EndArray(vec.size());
 }
 
 template <typename Vec>
-typename std::enable_if<sfinae::is_vector_like<Vec>::value, void>::type fromJsonValue(const rapidjson::Value& val, Vec& vec)
+inline typename std::enable_if<sfinae::is_vector_like<Vec>::value, void>::type fromJsonValue(const rapidjson::Value& val, Vec& vec)
 {
   if (!val.IsArray())
   {