I am sending emails from my wordpress using SMTP Postman plugin. I have created a function in my functions.php file that creates a HTML registration email as per the below:

/* Custom user registration email */
function set_bp_message_content_type() {
    return 'text/html';

add_filter( 'bp_core_signup_send_validation_email_message', 'custom_buddypress_activation_message', 10, 3 );

function custom_buddypress_activation_message( $message, $user_id, $activate_url ) {
    add_filter( 'wp_mail_content_type', 'set_bp_message_content_type' );
    $user = get_userdata( $user_id );
    return '

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
  <title>Welcome to My Site</title>
  <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<body style="margin: 0; padding: 0;">


However, many email providers check email content for both an HTML and a plain text version. My emails currently send in HTML only. Is there a way with my current setup to send a HTML and a Plain text version?

1 Answer 1


Check to see if you can hook into phpmailer_init and set AltBody.

add_action('phpmailer_init', 'add_plain_text');

function add_plain_text($phpmailer)
    $phpmailer->AltBody = "This is a text message";

Bonus: pass your HTML through premailer.dialect.ca to render a usable text version and find more info on multipart email at Things I've Learned About Building & Coding HTML Email Templates.


Postman's test email is an example of a message that has both text and html parts. It's content type is "multipart/alternative" which is a MIME extension.

According to this support question on Postman SMTP Mailer the answer lies in the Postman's test email and sites this example. Just be sure to replace mail with wp_mail.

//specify the email address you are sending to, and the email subject
$email = '[email protected]';
$subject = 'Email Subject';

//create a boundary for the email. This 
$boundary = uniqid('np');

//headers - specify your from email address and name here
//and specify the boundary for the email
$headers = "MIME-Version: 1.0\r\n";
$headers .= "From: Your Name \r\n";
$headers .= "To: ".$email."\r\n";
$headers .= "Content-Type: multipart/alternative;boundary=" . $boundary . "\r\n";

//here is the content body
$message = "This is a MIME encoded message.";
$message .= "\r\n\r\n--" . $boundary . "\r\n";
$message .= "Content-type: text/plain;charset=utf-8\r\n\r\n";

//Plain text body
$message .= "Hello,\nThis is a text email, the text/plain version.
\n\nRegards,\nYour Name";
$message .= "\r\n\r\n--" . $boundary . "\r\n";
$message .= "Content-type: text/html;charset=utf-8\r\n\r\n";

//Html body
$message .= "
This is a text email, the html version.

Your Name";
$message .= "\r\n\r\n--" . $boundary . "--";

//invoke the PHP mail function
wp_mail('', $subject, $message, $headers);
  • Got an example i could use with my above code ? Im having difficulties with this. Dec 2, 2015 at 17:12
  • The answer has been updated to include links to a previously asked question on their support forum.
    – jgraup
    Dec 2, 2015 at 18:01
  • Maybe mail() works with an empty email address, but for me wp_mail() does not, so I used: wp_mail($email, $subject, $message, $headers);
    – Zade
    Jan 15, 2019 at 8:18
  • Also I couldn't get Gmail to display the message properly without adding the following header: Content-Transfer-Encoding: 7bit
    – Zade
    Jan 15, 2019 at 9:11

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