// Function to remove trailing slash for URLs when tracking_id is present function remove_trailing_slash_for_tracking_id($redirect, $request) { // Check if the query string contains tracking_id if (isset($_GET['tracking_id'])) { // If tracking_id is present, remove trailing slash from the URL $redirect = untrailingslashit($redirect); } // Return the modified or original redirect URL return $redirect; } // Hook the function to the redirect_canonical filter add_filter('redirect_canonical', 'remove_trailing_slash_for_tracking_id', 10, 2);