diff --git a/include/protocol.hh b/include/protocol.hh
index 4ddd155..ecf782e 100644
--- a/include/protocol.hh
+++ b/include/protocol.hh
@@ -4,6 +4,7 @@
 #include <string>
 #include <map>
 #include <vector>
+#include <cstdint>
 
 using std::vector;
 using std::map;