diff --git a/sarif/include/gap/sarif/sarif.hpp b/sarif/include/gap/sarif/sarif.hpp
index fc5649b..6356bc6 100644
--- a/sarif/include/gap/sarif/sarif.hpp
+++ b/sarif/include/gap/sarif/sarif.hpp
@@ -24,6 +24,44 @@
 
 #include <nlohmann/json.hpp>
 
+NLOHMANN_JSON_NAMESPACE_BEGIN
+
+    template< typename T >
+    struct adl_serializer< std::shared_ptr< T > > {
+        static void to_json(json &j, const std::shared_ptr< T > &opt) {
+            if (!opt)
+                j = nullptr;
+            else
+                j = *opt;
+        }
+
+        static std::shared_ptr< T > from_json(const json &j) {
+            if (j.is_null())
+                return std::make_shared< T >();
+            else
+                return std::make_shared< T >(j.get< T >());
+        }
+    };
+
+    template< typename T >
+    struct adl_serializer< std::optional< T > > {
+        static void to_json(json &j, const std::optional< T > &opt) {
+            if (!opt)
+                j = nullptr;
+            else
+                j = *opt;
+        }
+
+        static std::optional< T > from_json(const json &j) {
+            if (j.is_null())
+                return std::nullopt;
+            else
+                return std::make_optional< T >(j.get< T >());
+        }
+    };
+
+NLOHMANN_JSON_NAMESPACE_END
+
 namespace gap::sarif
 {
     using json = nlohmann::json;