diff --git a/headers/Containers/Hashing.hpp b/headers/Containers/Hashing.hpp
new file mode 100644
index 0000000..24d1ae2
--- /dev/null
+++ b/headers/Containers/Hashing.hpp
@@ -0,0 +1,21 @@
+/*
+ * SPDX-FileCopyrightText: Dora "cat" <cat@thenight.club>
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public License,
+ * v. 2.0. If a copy of the MPL was not distributed with this file, You can
+ * obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef GUARD_TOURMALINE_HASHING_H
+#define GUARD_TOURMALINE_HASHING_H
+#include <concepts>
+#include <functional>
+
+namespace Tourmaline::Containers {
+template <typename T>
+concept hashable = requires(T x) {
+  { std::hash<T>{x}() } -> std::convertible_to<std::size_t>;
+};
+} // namespace Tourmaline::Containers
+#endif