diff --git a/src/data/data_validate.cxx b/src/data/data_validate.cxx
index 9f3f7dc..59269b2 100644
--- a/src/data/data_validate.cxx
+++ b/src/data/data_validate.cxx
@@ -1,4 +1,5 @@
 #include "data_internal.hxx"
+#include <fstream>
 
 template<typename... Args>
 inline void ok(bool ok, spdlog::format_string_t<Args...> fmt, Args &&...args) {