diff --git a/src/allmydata/webish.py b/src/allmydata/webish.py
index cc26579c9..d241de014 100644
--- a/src/allmydata/webish.py
+++ b/src/allmydata/webish.py
@@ -1580,9 +1580,9 @@ class WebishServer(service.MultiService):
         # what is our webport?
         s = self.listener
         if isinstance(s, internet.TCPServer):
-            base_url = "http://127.0.0.1:%d" % s._port.getHost().port
+            base_url = "http://127.0.0.1:%d/" % s._port.getHost().port
         elif isinstance(s, internet.SSLServer):
-            base_url = "https://127.0.0.1:%d" % s._port.getHost().port
+            base_url = "https://127.0.0.1:%d/" % s._port.getHost().port
         else:
             base_url = None
         if base_url: