$re = '/https?:\/\/([^\/]+)\/es(\/|$)/m';
$str = 'http://localhost:3000/es
http://localhost:3000/es/
http://localhost:3000/es/some-post
https://my-site.com/es
https://my-site.com/es/
https://my-site.com/es/some-post
https://random-domain.something/es
https://random-domain.something/es/
https://random-domain.something/es/some-post
http://localhost:3000
http://localhost:3000/
http://localhost:3000/some-post
http://localhost:3000/es-some-post
https://my-site.com
https://my-site.com/
https://my-site.com/some-post
https://my-site.com/es-some-post
https://www.random-domain.something
https://www.random-domain.something/
https://www.random-domain.something/some-post
https://www.random-domain.something/es-some-post';
preg_match_all($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