$re = '/\/api\/ping(?=\.|\/|$)\S*/m';
$str = '/api/ping.json
/api/ping
/api/ping/xxx/sss.json
/api/ping.xml
and this should NOT match
/api/pingpong
/api/ping_pong
/api/ping-pong';
preg_match_all($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