diff --git a/src/cryptonote_core/cryptonote_core.cpp b/src/cryptonote_core/cryptonote_core.cpp
index 4c6536318f4..ab20b678abc 100644
--- a/src/cryptonote_core/cryptonote_core.cpp
+++ b/src/cryptonote_core/cryptonote_core.cpp
@@ -193,6 +193,12 @@ namespace cryptonote
   , "Run a program for each new block, '%s' will be replaced by the block hash"
   , ""
   };
+  static const command_line::arg_descriptor<std::string> arg_sync_notify = {
+    "sync-notify"
+  , "Run a program when we start or stop syncing, '%h' will be replaced by the "
+    "current height, '%t' by the target height, '%s' by 1 if synced, 0 if not."
+  , ""
+  };
   static const command_line::arg_descriptor<bool> arg_prune_blockchain  = {
     "prune-blockchain"
   , "Prune blockchain"
@@ -345,6 +351,7 @@ namespace cryptonote
     command_line::add_arg(desc, arg_sync_pruned_blocks);
     command_line::add_arg(desc, arg_max_txpool_weight);
     command_line::add_arg(desc, arg_block_notify);
+    command_line::add_arg(desc, arg_sync_notify);
     command_line::add_arg(desc, arg_prune_blockchain);
     command_line::add_arg(desc, arg_reorg_notify);
     command_line::add_arg(desc, arg_block_rate_notify);
@@ -647,6 +654,28 @@ namespace cryptonote
       MERROR("Failed to parse block notify spec: " << e.what());
     }
 
+    try
+    {
+      if (!command_line::is_arg_defaulted(vm, arg_sync_notify))
+      {
+        struct sync_notify
+        {
+          tools::Notify cmdline;
+
+          void operator()(bool syncing, std::uint64_t height, std::uint64_t target) const
+          {
+            cmdline.notify("%s", syncing ? "1" : " 0", "%h", std::to_string(height).c_str(), "%t", std::to_string(target).c_str(), NULL);
+          }
+        };
+
+        add_sync_notify(sync_notify{{command_line::get_arg(vm, arg_sync_notify).c_str()}});
+      }
+    }
+    catch (const std::exception &e)
+    {
+      MERROR("Failed to parse sync notify spec: " << e.what());
+    }
+
     try
     {
       if (!command_line::is_arg_defaulted(vm, arg_reorg_notify))
@@ -1451,6 +1480,32 @@ namespace cryptonote
     m_miner.resume();
   }
   //-----------------------------------------------------------------------------------------------
+  void core::add_sync_notify(boost::function<void(bool, std::uint64_t, std::uint64_t)>&& notify)
+  {
+    if (notify)
+    {
+      m_sync_notifiers.push_back(std::move(notify));
+    }
+  }
+  //-----------------------------------------------------------------------------------------------
+  void core::on_start_syncing(uint64_t target)
+  {
+    MINFO("Starting syncing");
+    const uint64_t current_blockchain_height = get_current_blockchain_height();
+    if (target >= current_blockchain_height + 5) // don't switch to unsafe mode just for a few blocks
+      safesyncmode(false);
+    for (const auto& notifier : m_sync_notifiers)
+      notifier(true, current_blockchain_height, target);
+  }
+  //-----------------------------------------------------------------------------------------------
+  void core::on_stop_syncing()
+  {
+    MINFO("Stopping syncing");
+    safesyncmode(true);
+    for (const auto& notifier : m_sync_notifiers)
+      notifier(false, get_current_blockchain_height(), 0);
+  }
+  //-----------------------------------------------------------------------------------------------
   block_complete_entry get_block_complete_entry(block& b, tx_memory_pool &pool)
   {
     block_complete_entry bce;
@@ -1537,7 +1592,12 @@ namespace cryptonote
   //-----------------------------------------------------------------------------------------------
   bool core::add_new_block(const block& b, block_verification_context& bvc)
   {
-    return m_blockchain_storage.add_new_block(b, bvc);
+    const bool syncing = get_current_blockchain_height() < get_target_blockchain_height();
+    if (!m_blockchain_storage.add_new_block(b, bvc))
+      return false;
+    if (syncing && get_current_blockchain_height() >= get_target_blockchain_height())
+      on_stop_syncing();
+    return true;
   }
 
   //-----------------------------------------------------------------------------------------------
@@ -2025,6 +2085,11 @@ namespace cryptonote
   //-----------------------------------------------------------------------------------------------
   void core::set_target_blockchain_height(uint64_t target_blockchain_height)
   {
+    const uint64_t height = get_current_blockchain_height();
+    if (m_target_blockchain_height > height && target_blockchain_height <= height)
+      on_stop_syncing();
+    else if (target_blockchain_height > height)
+      on_start_syncing(target_blockchain_height);
     m_target_blockchain_height = target_blockchain_height;
   }
   //-----------------------------------------------------------------------------------------------
diff --git a/src/cryptonote_core/cryptonote_core.h b/src/cryptonote_core/cryptonote_core.h
index d2bffdaee0e..069688cd67e 100644
--- a/src/cryptonote_core/cryptonote_core.h
+++ b/src/cryptonote_core/cryptonote_core.h
@@ -893,6 +893,16 @@ namespace cryptonote
       */
      bool get_txpool_complement(const std::vector<crypto::hash> &hashes, std::vector<cryptonote::blobdata> &txes);
 
+     /**
+       * @brief sets a sync notify object to call when we start/stop syncing
+      *
+      * @param notify the notify object to call
+      */
+     void add_sync_notify(boost::function<void(bool, uint64_t, uint64_t)> &&notify);
+
+     void on_start_syncing(uint64_t target);
+     void on_stop_syncing();
+
    private:
 
      /**
@@ -1131,6 +1141,8 @@ namespace cryptonote
 
      std::shared_ptr<tools::Notify> m_block_rate_notify;
      boost::function<void(std::vector<txpool_event>)> m_zmq_pub;
+
+     std::vector<boost::function<void(bool, std::uint64_t, std::uint64_t)>> m_sync_notifiers;
    };
 }
 
diff --git a/src/cryptonote_protocol/cryptonote_protocol_handler.h b/src/cryptonote_protocol/cryptonote_protocol_handler.h
index 80dd2bc391b..4f5315ad35e 100644
--- a/src/cryptonote_protocol/cryptonote_protocol_handler.h
+++ b/src/cryptonote_protocol/cryptonote_protocol_handler.h
@@ -111,6 +111,7 @@ namespace cryptonote
     void log_connections();
     std::list<connection_info> get_connections();
     const block_queue &get_block_queue() const { return m_block_queue; }
+    bool has_more_blocks_queued() const { return m_block_queue.get_data_size() > 0; }
     void stop();
     void on_connection_close(cryptonote_connection_context &context);
     void set_max_out_peers(unsigned int max) { m_max_out_peers = max; }
diff --git a/src/cryptonote_protocol/cryptonote_protocol_handler.inl b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
index 106253082ff..91d9958964f 100644
--- a/src/cryptonote_protocol/cryptonote_protocol_handler.inl
+++ b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
@@ -407,10 +407,6 @@ namespace cryptonote
       << " [Your node is " << abs_diff << " blocks (" << tools::get_human_readable_timespan((abs_diff - diff_v2) * DIFFICULTY_TARGET_V1 + diff_v2 * DIFFICULTY_TARGET_V2) << ") "
       << (0 <= diff ? std::string("behind") : std::string("ahead"))
       << "] " << ENDL << "SYNCHRONIZATION started");
-      if (hshd.current_height >= m_core.get_current_blockchain_height() + 5) // don't switch to unsafe mode just for a few blocks
-      {
-        m_core.safesyncmode(false);
-      }
       if (m_core.get_target_blockchain_height() == 0) // only when sync starts
       {
         m_sync_timer.resume();
@@ -2479,7 +2475,6 @@ skip:
       }
       m_core.on_synchronized();
     }
-    m_core.safesyncmode(true);
     m_p2p->clear_used_stripe_peers();
 
     // ask for txpool complement from any suitable node if we did not yet
diff --git a/src/daemon/daemon.cpp b/src/daemon/daemon.cpp
index 3f1885423c9..93d40eaae9d 100644
--- a/src/daemon/daemon.cpp
+++ b/src/daemon/daemon.cpp
@@ -121,6 +121,7 @@ struct t_internals {
       {
         core.get().get_blockchain_storage().add_block_notify(cryptonote::listener::zmq_pub::chain_main{shared});
         core.get().get_blockchain_storage().add_miner_notify(cryptonote::listener::zmq_pub::miner_data{shared});
+        core.get().add_sync_notify(cryptonote::listener::zmq_pub::sync{shared});
         core.get().set_txpool_listener(cryptonote::listener::zmq_pub::txpool_add{shared});
       }
     }
diff --git a/src/rpc/zmq_pub.cpp b/src/rpc/zmq_pub.cpp
index 074b552078f..8882bfec7d6 100644
--- a/src/rpc/zmq_pub.cpp
+++ b/src/rpc/zmq_pub.cpp
@@ -57,9 +57,11 @@
 namespace
 {
   constexpr const char txpool_signal[] = "tx_signal";
+  constexpr const char sync_signal[] = "sync_signal";
 
   using chain_writer =  void(epee::byte_stream&, std::uint64_t, epee::span<const cryptonote::block>);
   using miner_writer =  void(epee::byte_stream&, uint8_t, uint64_t, const crypto::hash&, const crypto::hash&, cryptonote::difficulty_type, uint64_t, uint64_t, const std::vector<cryptonote::tx_block_template_backlog_entry>&);
+  using sync_writer =  void(epee::byte_stream&, bool, std::uint64_t, std::uint64_t);
   using txpool_writer = void(epee::byte_stream&, epee::span<const cryptonote::txpool_event>);
 
   template<typename F>
@@ -132,6 +134,14 @@ namespace
     const std::vector<cryptonote::tx_block_template_backlog_entry>& tx_backlog;
   };
 
+  //! Object for sync notification serialization
+  struct minimal_sync
+  {
+    const bool syncing;
+    const std::uint64_t height;
+    const std::uint64_t target;
+  };
+
   //! Object for "minimal" tx serialization
   struct minimal_txpool
   {
@@ -187,6 +197,17 @@ namespace
     dest.EndObject();
   }
 
+  void toJsonValue(rapidjson::Writer<epee::byte_stream>& dest, const minimal_sync self)
+  {
+    namespace adapt = boost::adaptors;
+
+    dest.StartObject();
+    INSERT_INTO_JSON_OBJECT(dest, syncing, self.syncing);
+    INSERT_INTO_JSON_OBJECT(dest, height, self.height);
+    INSERT_INTO_JSON_OBJECT(dest, target, self.target);
+    dest.EndObject();
+  }
+
   void json_full_chain(epee::byte_stream& buf, const std::uint64_t height, const epee::span<const cryptonote::block> blocks)
   {
     json_pub(buf, blocks);
@@ -202,6 +223,11 @@ namespace
     json_pub(buf, miner_data{major_version, height, prev_id, seed_hash, diff, median_weight, already_generated_coins, tx_backlog});
   }
 
+  void json_minimal_sync(epee::byte_stream& buf, bool syncing, const std::uint64_t height, const std::uint64_t target)
+  {
+    json_pub(buf, minimal_sync{syncing, height, target});
+  }
+
   // boost::adaptors are in place "views" - no copy/move takes place
   // moving transactions (via sort, etc.), is expensive!
 
@@ -236,6 +262,12 @@ namespace
     {u8"json-full-miner_data", json_miner_data},
   }};
 
+  constexpr const std::array<context<sync_writer>, 2> sync_contexts =
+  {{
+    {u8"json-full-sync", json_minimal_sync},
+    {u8"json-minimal-sync", json_minimal_sync},
+  }};
+
   constexpr const std::array<context<txpool_writer>, 2> txpool_contexts =
   {{
     {u8"json-full-txpool_add", json_full_txpool},
@@ -336,7 +368,7 @@ namespace
       zmq_msg_size(std::addressof(msg))
     };
 
-    if (payload == txpool_signal)
+    if (payload == txpool_signal || payload == sync_signal)
     {
       zmq_msg_close(std::addressof(msg));
       return false;
@@ -360,6 +392,7 @@ zmq_pub::zmq_pub(void* context)
   : relay_(),
     chain_subs_{{0}},
     miner_subs_{{0}},
+    sync_subs_({0}),
     txpool_subs_{{0}},
     sync_()
 {
@@ -368,6 +401,7 @@ zmq_pub::zmq_pub(void* context)
 
   verify_sorted(chain_contexts, "chain_contexts");
   verify_sorted(miner_contexts, "miner_contexts");
+  verify_sorted(sync_contexts, "sync_contexts");
   verify_sorted(txpool_contexts, "txpool_contexts");
 
   relay_.reset(zmq_socket(context, ZMQ_PAIR));
@@ -389,12 +423,13 @@ bool zmq_pub::sub_request(boost::string_ref message)
 
     const auto chain_range = get_range(chain_contexts, message);
     const auto miner_range = get_range(miner_contexts, message);
+    const auto sync_range = get_range(sync_contexts, message);
     const auto txpool_range = get_range(txpool_contexts, message);
 
-    if (!chain_range.empty() || !miner_range.empty() || !txpool_range.empty())
+    if (!chain_range.empty() || !miner_range.empty() || !sync_range.empty() || !txpool_range.empty())
     {
       MDEBUG("Client " << (tag ? "subscribed" : "unsubscribed") << " to " <<
-             chain_range.size() << " chain topic(s), " << miner_range.size() << " miner topic(s) and " << txpool_range.size() << " txpool topic(s)");
+             chain_range.size() << " chain topic(s), " << miner_range.size() << " miner topic(s), " << sync_range.size() << " sync topic(s) and " << txpool_range.size() << " txpool topic(s)");
 
       const boost::lock_guard<boost::mutex> lock{sync_};
       switch (tag)
@@ -402,11 +437,13 @@ bool zmq_pub::sub_request(boost::string_ref message)
       case 0:
         remove_subscriptions(chain_subs_, chain_range, chain_contexts.begin());
         remove_subscriptions(miner_subs_, miner_range, miner_contexts.begin());
+        remove_subscriptions(sync_subs_, sync_range, sync_contexts.begin());
         remove_subscriptions(txpool_subs_, txpool_range, txpool_contexts.begin());
         return true;
       case 1:
         add_subscriptions(chain_subs_, chain_range, chain_contexts.begin());
         add_subscriptions(miner_subs_, miner_range, miner_contexts.begin());
+        add_subscriptions(sync_subs_, sync_range, sync_contexts.begin());
         add_subscriptions(txpool_subs_, txpool_range, txpool_contexts.begin());
         return true;
       default:
@@ -498,6 +535,20 @@ std::size_t zmq_pub::send_miner_data(uint8_t major_version, uint64_t height, con
   return 0;
 }
 
+std::size_t zmq_pub::send_sync(bool syncing, std::uint64_t height, std::uint64_t target)
+{
+  const boost::lock_guard<boost::mutex> lock{sync_};
+  for (const std::size_t sub : sync_subs_)
+  {
+    if (sub)
+    {
+        auto messages = make_pubs(sync_subs_, sync_contexts, syncing, height, target);
+        return send_messages(relay_.get(), messages);
+    }
+  }
+  return 0;
+}
+
 std::size_t zmq_pub::send_txpool_add(std::vector<txpool_event> txes)
 {
   if (txes.empty())
@@ -537,6 +588,15 @@ void zmq_pub::miner_data::operator()(uint8_t major_version, uint64_t height, con
     MERROR("Unable to send ZMQ/Pub - ZMQ server destroyed");
 }
 
+void zmq_pub::sync::operator()(bool syncing, std::uint64_t height, std::uint64_t target) const
+{
+  const std::shared_ptr<zmq_pub> self = self_.lock();
+  if (self)
+    self->send_sync(syncing, height, target);
+  else
+    MERROR("Unable to send ZMQ/Pub - ZMQ server destroyed");
+}
+
 void zmq_pub::txpool_add::operator()(std::vector<cryptonote::txpool_event> txes) const
 {
   const std::shared_ptr<zmq_pub> self = self_.lock();
diff --git a/src/rpc/zmq_pub.h b/src/rpc/zmq_pub.h
index c636e1d7b37..d5e25c2bb87 100644
--- a/src/rpc/zmq_pub.h
+++ b/src/rpc/zmq_pub.h
@@ -61,6 +61,7 @@ class zmq_pub
     std::deque<std::vector<txpool_event>> txes_;
     std::array<std::size_t, 2> chain_subs_;
     std::array<std::size_t, 1> miner_subs_;
+    std::array<std::size_t, 2> sync_subs_;
     std::array<std::size_t, 2> txpool_subs_;
     boost::mutex sync_; //!< Synchronizes counts in `*_subs_` arrays.
 
@@ -95,6 +96,11 @@ class zmq_pub
         \return Number of ZMQ messages sent to relay. */
     std::size_t send_miner_data(uint8_t major_version, uint64_t height, const crypto::hash& prev_id, const crypto::hash& seed_hash, difficulty_type diff, uint64_t median_weight, uint64_t already_generated_coins, const std::vector<tx_block_template_backlog_entry>& tx_backlog);
 
+    /*! Send a `ZMQ_PUB` notification when starting/stopping syncing.
+        Thread-safe.
+        \return Number of ZMQ messages sent to relay. */
+    std::size_t send_sync(bool syncing, std::uint64_t height, std::uint64_t target);
+
     /*! Send a `ZMQ_PUB` notification for new tx(es) being added to the local
         pool. Thread-safe.
         \return Number of ZMQ messages sent to relay. */
@@ -114,6 +120,13 @@ class zmq_pub
       void operator()(uint8_t major_version, uint64_t height, const crypto::hash& prev_id, const crypto::hash& seed_hash, difficulty_type diff, uint64_t median_weight, uint64_t already_generated_coins, const std::vector<tx_block_template_backlog_entry>& tx_backlog) const;
     };
 
+    //! Callable for `send_sync` with weak ownership to `zmq_pub` object.
+    struct sync
+    {
+      std::weak_ptr<zmq_pub> self_;
+      void operator()(bool, std::uint64_t height, std::uint64_t target) const;
+    };
+
     //! Callable for `send_txpool_add` with weak ownership to `zmq_pub` object.
     struct txpool_add
     {