diff --git a/ampel-firmware/web_server.h b/ampel-firmware/web_server.h
index ed1b65dc26dee2dc5dd3d5ce27a6e1e5acea66ff..bc2c0101fca661d1d7cd0db5ff922851b0224e58 100644
--- a/ampel-firmware/web_server.h
+++ b/ampel-firmware/web_server.h
@@ -9,6 +9,7 @@
 
 #include "config.h"
 #include "util.h"
+#include "wifi_util.h"
 #include "co2_sensor.h"
 #include "sensor_console.h"
 #ifdef AMPEL_CSV