$re = '/^(vertretung)?.*payback+\W++[a-z]?/mU';
$str = 'payback/
payback/?
payback/?AZMEDID=123
payback/?AZMEDID=123#abd
payback/#abd
payback/DoNOTmatchthis1
payback
paybackdonotmatchthis
vertretung/daisy.maus/payback/
vertretung/daisy.maus/payback
vertretung/daisy.maus/payback/?AZMEDID=123
vertretung/daisy.maus/payback/?AZMEDID=123#abd
vertretung/daisy.maus/payback/#abd
vertretung/daisy.maus/payback/DoNOTmatchthis1
vertretung/daisy.maus/paybackDoNOTmatchthis
vertretung/daisy.maus/payback/# ';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php