diff --git a/src/transfer.h b/src/transfer.h
index 8c6a9f4..0c7a970 100644
--- a/src/transfer.h
+++ b/src/transfer.h
@@ -9,6 +9,7 @@
 
 #ifndef TRANSFER_H
 #define TRANSFER_H 1
+#include <stdint.h>
 
 typedef struct b64_buffer {
     char * ptr;