I'm trying to send an invitation to someone to become a user of a private Wordpress blog, but WP apparently doesn't accept an apostrophe appearing in the name in the email address as valid. For example, it seems it would consider maryo'[email protected] as an invalid email address, because of the apostrophe in Mary's surname. Has anyone else had this problem, and is there a way around it, by substituting a different character in place of the apostrophe?


1 Answer 1


Filter is_email and sanitize_email, then apply a better check:

namespace Wpse\Email;

add_filter( 'is_email',       __NAMESPACE__ . '\check_mail_address', 10, 2 );
add_filter( 'sanitize_email', __NAMESPACE__ . '\check_mail_address', 10, 2 );

function check_mail_address( $result, $email )
    return filter_var( $email, FILTER_VALIDATE_EMAIL );

The PHP function is still not RFC 5321 compliant, but better than the WordPress check.

  • A better check would be return filter_var($email, FILTER_VALIDATE_EMAIL) && preg_match('/@.+\./', $email); Source
    – user40422
    May 21, 2015 at 13:40
  • @Bondye I wrote this especially to allow me the use of my local addresses.
    – fuxia
    May 21, 2015 at 13:41
  • Ok, sorry for the misunderstanding. Maybe rename the function to check_mail_local ;)
    – user40422
    May 21, 2015 at 13:43
  • nice and short (I thought WordPress would never include a code with the PHP filter_* functions, so I was surprised to find it in one place, the class-phpmailer.php class ;-)
    – birgire
    May 21, 2015 at 14:17

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