diff --git a/include/mp/flat/constr_keeper.h b/include/mp/flat/constr_keeper.h
index 8360204f8..00f6b3337 100644
--- a/include/mp/flat/constr_keeper.h
+++ b/include/mp/flat/constr_keeper.h
@@ -660,6 +660,7 @@ class ConstraintKeeper final
   ConstraintKeeper(Converter& cvt, const char* nm, const char* optnm) :
       BasicConstraintKeeper(cvt.GetValuePresolver(), nm, optnm), cvt_(cvt)
   {
+    GetValueNode().SetName(GetShortTypeName());  // change value node name
     GetConverter().AddConstraintKeeper(*this, ConversionPriority());
   }
 
@@ -880,7 +881,7 @@ class ConstraintKeeper final
       fmt::MemoryWriter wrt;
       {
         MiniJSONWriter jw(wrt);
-        jw["con_type"] = GetShortTypeName();
+        jw["CON_TYPE"] = GetShortTypeName();
         jw["index"] = i_con;
         jw["depth"] = cnt.GetDepth();
         //      wrt.write("\"data\": ");
diff --git a/include/mp/flat/converter_model.h b/include/mp/flat/converter_model.h
index b2a84c157..b7046f8ef 100644
--- a/include/mp/flat/converter_model.h
+++ b/include/mp/flat/converter_model.h
@@ -74,7 +74,7 @@ class FlatModel
       fmt::MemoryWriter wrt;
       {
         MiniJSONWriter jw(wrt);
-        jw["var_index"] = i+i_start;
+        jw["VAR_INDEX"] = i+i_start;
         jw["bounds"] << lbs[i] << ubs[i];
         jw["type"] = (int)types[i];
         jw["is_from_nl"] = (int)is_var_original(i);
@@ -238,7 +238,7 @@ class FlatModel
       fmt::MemoryWriter wrt;
       {
         MiniJSONWriter jw(wrt);
-        jw["obj_index"] = i_obj;
+        jw["OBJ_INDEX"] = i_obj;
         jw["sense"] = (int)obj.obj_sense();
         wrt.write("\"qp_terms\": ");
         WriteJSON(wrt, obj.GetQPTerms());
diff --git a/include/mp/valcvt.h b/include/mp/valcvt.h
index 2627b2c3a..3d60b868f 100644
--- a/include/mp/valcvt.h
+++ b/include/mp/valcvt.h
@@ -192,7 +192,7 @@ class ValuePresolverImpl : public BasicValuePresolver {
         MiniJSONWriter jw(wrt);
         jw["link_index"] = std::make_tuple(i_exported_, i_entry);
         jw["link_type"] = ln.GetTypeName();
-        WriteNodes(jw["source_nodes"], entry_items_.src_items_);
+        WriteNodes(jw["src_nodes"], entry_items_.src_items_);
         WriteNodes(jw["dest_nodes"], entry_items_.dest_items_);
       }
       /// Export record