diff --git a/include/builtin/types.h b/include/builtin/types.h
new file mode 100644
index 0000000..1bdd649
--- /dev/null
+++ b/include/builtin/types.h
@@ -0,0 +1,11 @@
+#pragma once
+
+#include <cinttypes>
+
+namespace jaclks {
+
+typedef std::size_t Size_t;
+
+typedef std::uint32_t UInt32_t;
+
+}  // namespace jaclks
diff --git a/include/hash/types.h b/include/hash/types.h
new file mode 100644
index 0000000..8f03bf6
--- /dev/null
+++ b/include/hash/types.h
@@ -0,0 +1,9 @@
+#pragma once
+
+#include "jaclks/builtin/types.h"
+
+namespace jaclks {
+
+typedef Size_t Hash_t;
+
+}  // namespace jaclks
diff --git a/include/jaclks/hash/hasher.h b/include/jaclks/hash/hasher.h
index be5dc8e..26a18d6 100644
--- a/include/jaclks/hash/hasher.h
+++ b/include/jaclks/hash/hasher.h
@@ -4,19 +4,20 @@
 #include <unordered_map>
 
 #include "jaclks/compile/type_traits.h"
+#include "jaclks/hash/types.h"
 
 namespace jaclks {
 
 template <typename T, typename = void>
 struct Hasher {
-  std::size_t operator()(const T &x) const noexcept {
+  Hash_t operator()(const T &x) const noexcept {
     return std::hash<T>{}(x);
   }
 };
 
 template <typename T>
 struct Hasher<T *> {
-  std::size_t operator()(const T *x) const noexcept {
+  Hash_t operator()(const T *x) const noexcept {
     if (x == nullptr) {
       return 0;
     }
@@ -28,7 +29,7 @@ template <typename T>
 struct Hasher<T, std::enable_if_t<is_smart_pointer_v<T>>> {
   using Type = std::decay_t<typename T::element_type>;
 
-  std::size_t operator()(const T &x) const noexcept {
+  Hash_t operator()(const T &x) const noexcept {
     if (x == nullptr) {
       return 0;
     }