diff --git a/maubot/__meta__.py b/maubot/__meta__.py
index 2c6a6e1..83a708f 100644
--- a/maubot/__meta__.py
+++ b/maubot/__meta__.py
@@ -1 +1 @@
-__version__ = "0.1.0.dev29"
+__version__ = "0.1.0.dev30"
diff --git a/maubot/plugin_base.py b/maubot/plugin_base.py
index b0e9383..b2608c8 100644
--- a/maubot/plugin_base.py
+++ b/maubot/plugin_base.py
@@ -50,7 +50,7 @@ class Plugin(ABC):
         self.config = config
         self.database = database
         self.webapp = webapp
-        self.webapp_url = URL(webapp_url)
+        self.webapp_url = URL(webapp_url) if webapp_url else None
         self._handlers_at_startup = []
 
     def register_handler_class(self, obj) -> None: