diff --git a/src/Serialization/Json.cpp b/src/Serialization/Json.cpp
index bce661d..3baa3c0 100644
--- a/src/Serialization/Json.cpp
+++ b/src/Serialization/Json.cpp
@@ -381,7 +381,7 @@ namespace Tesses::Framework::Serialization::Json
                     }
                     else
                     {
-                        return std::stoll(tkn.first);
+                        return (int64_t)std::stoll(tkn.first);
                     }
                 }