diff --git a/config.yaml b/config.yaml
index 0671032..d08e641 100755
--- a/config.yaml
+++ b/config.yaml
@@ -32,4 +32,4 @@ service:
 probing_webserver:
   host: $PROBING_WEBSERVER_HOST|"0.0.0.0"  # Probe webserver address
   port: $PROBING_WEBSERVER_PORT|8080  # Probe webserver port
-  mode: "development"
+  mode: $PROBING_WEBSERVER_MODE|production  # webserver mode: {development, production}
diff --git a/pyinfra/flask.py b/pyinfra/flask.py
index 58cd300..e8eac08 100644
--- a/pyinfra/flask.py
+++ b/pyinfra/flask.py
@@ -13,7 +13,7 @@ def run_probing_webserver(app, host=None, port=None, mode=None):
         port = CONFIG.probing_webserver.port
 
     if not mode:
-        mode = CONFIG.probing_webserver.port
+        mode = CONFIG.probing_webserver.mode
 
     if mode == "development":
         app.run(host=host, port=port, debug=True)
@@ -38,4 +38,4 @@ def set_up_probing_webserver():
         resp.status_code = 200
         return resp
 
-    return app
\ No newline at end of file
+    return app