diff --git a/code/json/marshaling.hxx b/code/json/marshaling.hxx
index f58cdee..4a2d395 100644
--- a/code/json/marshaling.hxx
+++ b/code/json/marshaling.hxx
@@ -68,11 +68,27 @@ namespace code::json
 
   };
 
-  template<member_name_t Name, auto Member>
+  template<typename, typename = std::void_t<>>
+  struct has_validator
+    : std::false_type
+  {};
+
+  template<typename T>
+  struct has_validator<
+      T,
+      std::void_t<
+        decltype(std::declval<T const&>().validate(std::declval<marshaling_context_t*>()))
+      >
+    >
+    : std::true_type
+  {};
+
+  template<member_name_t Name, auto Member, typename Validator = void>
   struct member_t
   {
     using T = member_traits<decltype(Member)>::class_type;
     using M = member_traits<decltype(Member)>::member_type;
+    using V = Validator;
 
     static constexpr bool is_optional{
       is_optional_v<M>
@@ -97,7 +113,13 @@ namespace code::json
         throw std::runtime_error{"missing field '" + Name.str() + "'"};
       }
 
-      instance.*Member = marshaling_traits<M>::unmarshal(v.get(Name), context);
+      M value = marshaling_traits<M>::unmarshal(v.get(Name), context);
+
+      if constexpr (!std::is_same_v<V, void>) {
+        V::validate(value, context);
+      }
+
+      instance.*Member = std::move(value);
     }
 
     struct pointer_t
@@ -133,7 +155,13 @@ namespace code::json
           throw std::runtime_error{ "missing field '" + to_string(ptr()) + "'" };
         }
 
-        instance.*Member = marshaling_traits<M>::unmarshal(*ptr_v, context);
+        M value = marshaling_traits<M>::unmarshal(*ptr_v, context);
+
+        if constexpr (!std::is_same_v<V, void>) {
+          V::validate(value, context);
+        }
+
+        instance.*Member = std::move(value);
       }
 
     };
@@ -168,6 +196,10 @@ namespace code::json
     {
       First::unmarshal(instance, v, context);
       ((Members::unmarshal(instance, v, context)), ...);
+
+      if constexpr (has_validator<T>::value) {
+        instance.validate(context);
+      }
     }
 
     static
@@ -209,6 +241,10 @@ namespace code::json
         ((Bases::json::do_unmarshal(instance, v, context)), ...);
         First::unmarshal(instance, v, context);
         ((Members::unmarshal(instance, v, context)), ...);
+
+        if constexpr (has_validator<T>::value) {
+          instance.validate(context);
+        }
       }
 
       static