diff --git a/server/core/query_classifier.cc b/server/core/query_classifier.cc
index 8947563b0..aeeb25e1b 100644
--- a/server/core/query_classifier.cc
+++ b/server/core/query_classifier.cc
@@ -26,6 +26,8 @@
 #include <maxscale/modutil.hh>
 #include <maxscale/pcre2.h>
 #include <maxscale/utils.h>
+#include <maxscale/jansson.hh>
+#include <maxscale/buffer.hh>
 
 #include "internal/config_runtime.h"
 #include "internal/modules.h"