diff --git a/src/ripple/basics/base64.h b/src/ripple/basics/base64.h
index ef34192..05a6113 100644
--- a/src/ripple/basics/base64.h
+++ b/src/ripple/basics/base64.h
@@ -57,6 +57,7 @@
 #ifndef RIPPLE_BASICS_BASE64_H_INCLUDED
 #define RIPPLE_BASICS_BASE64_H_INCLUDED
 
+#include <cstdint>
 #include <string>
 
 namespace ripple {