diff --git a/libervia/backend/tools/common/template.py b/libervia/backend/tools/common/template.py
index a71a236e..f0bd11a0 100644
--- a/libervia/backend/tools/common/template.py
+++ b/libervia/backend/tools/common/template.py
@@ -482,6 +482,8 @@ class Renderer(object):
         self.env.filters["highlight"] = self.highlight
         self.env.filters["front_url"] = (self._front_url if front_url_filter is None
                                          else front_url_filter)
+        self.env.filters["media_type_main"] = self.media_type_main
+        self.env.filters["media_type_sub"] = self.media_type_sub
         # custom tests
         self.env.tests["in_the_past"] = self._in_the_past
         self.icons_path = os.path.join(host.media_dir, "fonts/fontello/svg")
@@ -924,6 +926,18 @@ class Renderer(object):
         formatter = formatters.HtmlFormatter(**html_fmt_opts)
         return safe(pygments.highlight(code, lexer, formatter))
 
+    def media_type_main(self, value: Optional[str]) -> Optional[str]:
+        """Return main type of a media type"""
+        if not value:
+            return None
+        return value.partition("/")[0]
+
+    def media_type_sub(self, value: Optional[str]) -> Optional[str]:
+        """Return main type of a media type"""
+        if not value:
+            return None
+        return value.partition("/")[1]
+
     ## custom tests ##
 
     def _in_the_past(self, timestamp):