diff --git a/mkdocs_rss_plugin/config.py b/mkdocs_rss_plugin/config.py
index a1be4e5b..ea25a265 100644
--- a/mkdocs_rss_plugin/config.py
+++ b/mkdocs_rss_plugin/config.py
@@ -18,14 +18,14 @@ class RssPluginConfig(Config):
 
     abstract_chars_count = config_options.Type(int, default=160)
     abstract_delimiter = config_options.Type(str, default="<!-- more -->")
-    categories = config_options.Type(list, default=None)
-    comments_path = config_options.Type(str, default=None)
-    date_from_meta = config_options.Type(dict, default=None)
+    categories = config_options.ListOfItems(config_options.Type(str), default=[])
+    comments_path = config_options.Optional(config_options.Type(str))
+    date_from_meta = config_options.Optional(config_options.Type(dict))
     enabled = config_options.Type(bool, default=True)
     feed_ttl = config_options.Type(int, default=1440)
-    image = config_options.Type(str, default=None)
+    image = config_options.Optional(config_options.Type(str))
     length = config_options.Type(int, default=20)
     match_path = config_options.Type(str, default=".*")
     pretty_print = config_options.Type(bool, default=False)
-    url_parameters = config_options.Type(dict, default=None)
+    url_parameters = config_options.Optional(config_options.Type(dict))
     use_git = config_options.Type(bool, default=True)
diff --git a/mkdocs_rss_plugin/plugin.py b/mkdocs_rss_plugin/plugin.py
index 31e760ac..3a121e1b 100644
--- a/mkdocs_rss_plugin/plugin.py
+++ b/mkdocs_rss_plugin/plugin.py
@@ -89,23 +89,23 @@ def on_config(self, config: config_options.Config) -> dict:
 
         # start a feed dictionary using global config vars
         base_feed = {
-            "author": config.get("site_author", None),
+            "author": config.site_author or None,
             "buildDate": formatdate(get_build_timestamp()),
-            "copyright": config.get("copyright", None),
-            "description": config.get("site_description", None),
+            "copyright": config.copyright,
+            "description": config.site_description,
             "entries": [],
             "generator": f"{__title__} - v{__version__}",
             "html_url": self.util.get_site_url(config),
             "language": self.util.guess_locale(config),
             "pubDate": formatdate(get_build_timestamp()),
-            "repo_url": config.get("repo_url", config.get("site_url", None)),
+            "repo_url": config.repo_url,
             "title": config.get("site_name", None),
-            "ttl": self.config.get("feed_ttl", None),
+            "ttl": self.config.feed_ttl,
         }
 
         # feed image
-        if self.config.get("image"):
-            base_feed["logo_url"] = self.config.get("image")
+        if self.config.image:
+            base_feed["logo_url"] = self.config.image
 
         # pattern to match pages included in output
         self.match_path_pattern = compile(self.config.get("match_path"))