It wasn't working if( file_exists( $_SERVER[ "DOCUMENT_ROOT" ] ."/typo3conf/realurl_autoconf.php" ) ) { $GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['realurl']['decodeSpURL_preProc']["ric_test"] = 'EXT:sara_nuvap/Classes/Hooks/Realurl.php:SARA\\SaraNuvap\\Hooks\\Realurl->decodeSpURL_preProc'; } THIS works