How do I get the base URL from the feed content?
A way to do this would be to override the proprocess function get the domain like this:

function MY_MODULE_preprocess_views_view_field(&amp;$variables) {
  $field = $variables['field'];

  if ($field-&gt;field == 'MY_LINK_FIELD_NAME') {
    $url = $variables['field']-&gt;getValue($variables['row'])[0];
    $parse = parse_url($url);
    $variables['output'] = $parse['host'];
  }
}