diff --git a/lib/opencdd/exporters/json.rb b/lib/opencdd/exporters/json.rb
index 6637cbc..88e9c22 100644
--- a/lib/opencdd/exporters/json.rb
+++ b/lib/opencdd/exporters/json.rb
@@ -57,6 +57,10 @@ def visit_list_of_unit(lou)
         @nodes << list_of_unit_node(lou)
       end
 
+      def visit_det_classification(det)
+        @nodes << det_classification_node(det)
+      end
+
       # ─────────────────────────────────────────────────────────────
       # Public per-entity payload API
       #
diff --git a/lib/opencdd/visitor.rb b/lib/opencdd/visitor.rb
index 249498e..71da156 100644
--- a/lib/opencdd/visitor.rb
+++ b/lib/opencdd/visitor.rb
@@ -19,6 +19,7 @@ def visit_database(database)
       visit_relations(database)
       visit_view_controls(database)
       visit_list_of_units(database)
+      visit_det_classifications(database)
       self
     end
 
@@ -60,6 +61,10 @@ def visit_list_of_units(database)
       each_sorted(database.list_of_units) { |l| visit_list_of_unit(l) }
     end
 
+    def visit_det_classifications(database)
+      each_sorted(database.det_classifications) { |d| visit_det_classification(d) }
+    end
+
     # Single source of truth for sort-by-code traversal. Was
     # duplicated as `.sort_by { |x| x.code.to_s }` in 7 methods.
     def each_sorted(entities)