diff --git a/tokenizer/base64.h b/tokenizer/base64.h
index dfeefef55..12b8703a8 100644
--- a/tokenizer/base64.h
+++ b/tokenizer/base64.h
@@ -25,6 +25,7 @@
 #pragma once
 
 #include <cassert>
+#include <cstdint>
 #include <string>
 #include <string_view>