PHPMailer SMTP Code for use with WordPress

phpmailer-sample.php

<?php 

// The code below will allow you to use SMTP in WordPress with no plugin needed.

//-------------

// Place this code in functions.php inside your theme, in a Custom Plugin (plugins) or a Must Use Plugin (mu-plugins).
// Configures SMTP authentication
add_action( 'phpmailer_init', 'send_smtp_email' );
function send_smtp_email( $phpmailer ) {
    $phpmailer->isSMTP();
    $phpmailer->Host       = SMTP_HOST;
    $phpmailer->SMTPAuth   = SMTP_AUTH;
    $phpmailer->Port       = SMTP_PORT;
    $phpmailer->Username   = SMTP_USER;
    $phpmailer->Password   = SMTP_PASS;
    $phpmailer->SMTPSecure = SMTP_SECURE;
    $phpmailer->From       = SMTP_FROM;
    $phpmailer->FromName   = SMTP_NAME;
}

//-------------

// Place this code in wp-config.php
// Configures WordPress to use SMTP server
define( 'SMTP_USER',   'username' );  // Username to use for SMTP authentication
define( 'SMTP_PASS',   'password' );  // Password to use for SMTP authentication
define( 'SMTP_HOST',   'smtp.server.com' );  // The hostname of the mail server
define( 'SMTP_FROM',   'from@emailaddress.tld' );  // SMTP From email address
define( 'SMTP_NAME',   'Jane Doe' );  // SMTP From name
define( 'SMTP_PORT',   '587' );  // SMTP port number - likely to be 25, 465 or 587
define( 'SMTP_SECURE', 'PHPMailer::ENCRYPTION_STARTTLS' );  // Encryption system to use - ssl or tls
define( 'SMTP_AUTH',    true );  // Use SMTP authentication (true|false)
define( 'SMTP_DEBUG',   0 );  // for debugging purposes only set to 1 or 2

//-------------

/*
I was using the following settings in LocalWP but this caused the site to crash and stop responding.
I recommend you use PHPMailer::ENCRYPTION_STARTTLS and port 587 instead of tls and 25 when using PostMarkApp.com and LocalWP as
tls and port 25 didn't work longterm locally.

define( 'SMTP_PORT',   '25' );  // SMTP port number - likely to be 25, 465 or 587
define( 'SMTP_SECURE', 'tls' );  // Encryption system to use - ssl or tls
*/

//-------------

?>