diff --git a/rhodecode/config/middleware.py b/rhodecode/config/middleware.py
--- a/rhodecode/config/middleware.py
+++ b/rhodecode/config/middleware.py
@@ -315,6 +315,10 @@ def includeme(config):
     # Set the default renderer for HTML templates to mako.
     config.add_mako_renderer('.html')
 
+    config.add_renderer(
+        name='json_ext',
+        factory='rhodecode.lib.ext_json_renderer.pyramid_ext_json')
+
     # include RhodeCode plugins
     includes = aslist(settings.get('rhodecode.includes', []))
     for inc in includes:
diff --git a/rhodecode/lib/ext_json_renderer.py b/rhodecode/lib/ext_json_renderer.py
new file mode 100644
--- /dev/null
+++ b/rhodecode/lib/ext_json_renderer.py
@@ -0,0 +1,37 @@
+# -*- coding: utf-8 -*-
+
+# Copyright (C) 2010-2017 RhodeCode GmbH
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License, version 3
+# (only), as published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This program is dual-licensed. If you wish to learn more about the
+# RhodeCode Enterprise Edition, including its added features, Support services,
+# and proprietary license terms, please see https://rhodecode.com/licenses/
+
+from rhodecode.lib.ext_json import json
+
+
+def pyramid_ext_json(info):
+    """
+    Custom json renderer for pyramid to use our ext_json lib
+    """
+    def _render(value, system):
+        request = system.get('request')
+        if request is not None:
+            response = request.response
+            ct = response.content_type
+            if ct == response.default_content_type:
+                response.content_type = 'application/json'
+        return json.dumps(value)
+
+    return _render