diff --git a/include/rfl/json/Reader.hpp b/include/rfl/json/Reader.hpp
index ac86ad84..68d8e614 100644
--- a/include/rfl/json/Reader.hpp
+++ b/include/rfl/json/Reader.hpp
@@ -88,7 +88,8 @@ struct Reader {
     yyjson_obj_iter_init(_obj.val_, &iter);
     yyjson_val* key;
     while ((key = yyjson_obj_iter_next(&iter))) {
-      const auto name = std::string_view(yyjson_get_str(key), yyjson_get_len(key));
+      const auto name =
+          std::string_view(yyjson_get_str(key), yyjson_get_len(key));
       _object_reader.read(name, InputVarType(yyjson_obj_iter_get_val(key)));
     }
     return std::nullopt;
@@ -116,8 +117,8 @@ struct Reader {
       return static_cast<T>(yyjson_get_num(_var.val_));
 
     } else if constexpr (std::is_unsigned<std::remove_cvref_t<T>>()) {
-      if (!yyjson_is_int(_var.val_)) {
-        return error("Could not cast to int.");
+      if (!yyjson_is_uint(_var.val_)) {
+        return error("Could not cast to uint.");
       }
       return static_cast<T>(yyjson_get_uint(_var.val_));
 
diff --git a/tests/json/test_atomic_negative.cpp b/tests/json/test_atomic_negative.cpp
new file mode 100644
index 00000000..cb0e3ec3
--- /dev/null
+++ b/tests/json/test_atomic_negative.cpp
@@ -0,0 +1,26 @@
+#include <gtest/gtest.h>
+
+#include <atomic>
+#include <cstdint>
+#include <rfl.hpp>
+#include <rfl/json.hpp>
+
+namespace test_atomic_negative {
+
+struct TestObject {
+  std::uint64_t number{0};
+};
+
+struct AtomicTestObject {
+  std::atomic<std::uint64_t> number{0};
+};
+
+TEST(json, test_atomic_negative) {
+  auto req1 = rfl::json::read<TestObject>(R"({"number": -1})");
+  EXPECT_FALSE(req1.has_value());
+
+  auto req2 = rfl::json::read<rfl::Ref<AtomicTestObject>>(R"({"number": -1})");
+  EXPECT_FALSE(req2.has_value());
+}
+
+}  // namespace test_atomic_negative