diff --git a/Tr/TrackMonitors/src/BeamSpotMonitor.cpp b/Tr/TrackMonitors/src/BeamSpotMonitor.cpp
index 94fcf97390653a8d76c1ed289dd998c23bacdfca..ecf6852bf0b7e5d03d528cfb8b3b36b9800b5150 100644
--- a/Tr/TrackMonitors/src/BeamSpotMonitor.cpp
+++ b/Tr/TrackMonitors/src/BeamSpotMonitor.cpp
@@ -21,6 +21,7 @@
 #include <filesystem>
 #include <fstream>
 #include <mutex>
+#include <nlohmann/json.hpp>
 #include <optional>
 #include <regex>
 #include <sstream>
@@ -97,6 +98,8 @@ public:
     return Consumer::finalize();
   }
 
+  StatusCode stop() override;
+
   /// Internal representation of cached conditions
   struct IRConditionsCache {
     /// Cache variables
@@ -130,6 +133,8 @@ private:
   bool check_publish() const;
   bool ymlWriter() const;
 
+  void write_json_file( std::string const& ) const;
+
   /// Reset the accumulators
   bool check_reset_accumulators( const unsigned ) const;
   void reset_accumulators( const unsigned ) const;
@@ -229,6 +234,8 @@ private:
                                                    "/group/online/hlt/conditions.run3/lhcb-conditions-database" };
   Gaudi::Property<std::string> m_conditionsPathInDb{ this, "conditionsPathInDb",
                                                      "Conditions/LHCb/Online/InteractionRegion.yml/.pool" };
+  // bin file path
+  Gaudi::Property<std::string> m_json_name{ this, "JsonFile", "", "path where json file is saved" };
 
   /// Use IPublishSvc Online
   Gaudi::Property<bool>        m_onlineMode{ this, "OnlineMode", false, "Running in Online" };
@@ -500,6 +507,15 @@ StatusCode BeamSpotMonitor::initialize() {
   } );
 }
 
+StatusCode BeamSpotMonitor::stop() {
+  if ( m_json_name.value() != "" ) {
+    info() << "stopping and writing json file to" << m_json_name.value() << endmsg;
+    write_json_file( m_json_name );
+  }
+
+  return StatusCode::SUCCESS;
+}
+
 /// Initialize histograms that depende on properties
 void BeamSpotMonitor::init_configurable_histos() const {
   using axis1D = Gaudi::Accumulators::Axis<decltype( m_histPVPosX )::value_type::AxisArithmeticType>;
@@ -756,6 +772,45 @@ void BeamSpotMonitor::cache_counters() const {
   m_cache.spread[5] = m_pvZPosCtr.unbiased_sample_variance();
 }
 
+void BeamSpotMonitor::write_json_file( std::string const& filename ) const {
+
+  unsigned long n_entries      = m_pvXPosCtr.nEntries();
+  double        sum_x          = m_pvXPosCtr.sum();
+  double        sum_y          = m_pvYPosCtr.sum();
+  double        sum_z          = m_pvZPosCtr.sum();
+  double        sum2_x         = m_pvXPosCtr.sum2();
+  double        sum2_y         = m_pvYPosCtr.sum2();
+  double        sum2_z         = m_pvZPosCtr.sum2();
+  unsigned long n_entries_prod = m_pvXYProdCtr.nEntries();
+  double        sum_xy         = m_pvXYProdCtr.sum();
+  double        sum_zx         = m_pvZXProdCtr.sum();
+  double        sum_yz         = m_pvYZProdCtr.sum();
+  info() << "writing json file with: " << endmsg;
+  info() << "m_pvXPosCtr.nEntries: " << m_pvXPosCtr.nEntries() << " " << n_entries << endmsg;
+  info() << "m_pvXPosCtr.sum: " << m_pvXPosCtr.sum() << " " << sum_x << endmsg;
+  info() << "m_pvYPosCtr.sum: " << m_pvYPosCtr.sum() << " " << sum_y << endmsg;
+  info() << "m_pvZPosCtr.sum: " << m_pvZPosCtr.sum() << " " << sum_z << endmsg;
+  info() << "m_pvXPosCtr.sum2: " << m_pvXPosCtr.sum2() << " " << sum2_x << endmsg;
+  info() << "m_pvYPosCtr.sum2: " << m_pvYPosCtr.sum2() << " " << sum2_y << endmsg;
+  info() << "m_pvZPosCtr.sum2: " << m_pvZPosCtr.sum2() << " " << sum2_z << endmsg;
+  info() << "m_pvXYProdCtr.nEntries: " << m_pvXYProdCtr.nEntries() << " " << n_entries_prod << endmsg;
+  info() << " m_pvXYProdCtr.sum: " << m_pvXYProdCtr.sum() << " " << sum_xy << endmsg;
+  info() << " m_pvZXProdCtr.sum: " << m_pvZXProdCtr.sum() << " " << sum_zx << endmsg;
+  info() << " m_pvYZProdCtr.sum: " << m_pvYZProdCtr.sum() << " " << sum_yz << endmsg;
+
+  auto convert = []( auto const& c ) {
+    nlohmann::json out;
+    to_json( out, c );
+    return out;
+  };
+
+  std::ofstream o( filename );
+  o << nlohmann::json{ { "pvXPosCtr", convert( m_pvXPosCtr ) },     { "pvYPosCtr", convert( m_pvYPosCtr ) },
+                       { "pvZPosCtr", convert( m_pvZPosCtr ) },     { "pvXYProdCtr", convert( m_pvXYProdCtr ) },
+                       { "pvZXProdCtr", convert( m_pvZXProdCtr ) }, { "pvYZProdCtr", convert( m_pvYZProdCtr ) } }
+    << std::endl;
+}
+
 //=============================================================================
 // Reset the accumulators
 //=============================================================================