Configure WordPress to send email through an SMTP server.

readme.md

WordPress SMTP Configuration

Usage

1. Install and activate the smtp-config.php file as a plugin or drop it in /mu-plugins.
2. Define the necessary constants in wp-config.php.

Configuration Examples

MailHog

Route email through MailHog without authentication.

<?php
define( 'CEDARO_SMTP_HOST', 'localhost:1025' );

SparkPost

Send email using SparkPost.

<?php
define( 'CEDARO_SMTP_HOST', 'tls://smtp.sparkpostmail.com:587' );
define( 'CEDARO_SMTP_USERNAME', 'SMTP_Injection' );
define( 'CEDARO_SMTP_PASSWORD', '{password}' );

Bonus

To configure the default From Name and Email, add this snippet in the action callback:

$phpmailer->setFrom(
	apply_filters( 'wp_mail_from',      'from@example.com' ),
	apply_filters( 'wp_mail_from_name', 'Acme Company' )
);

smtp-config.php

<?php
/**
 * Plugin Name: SMTP Configuration
 */

/**
 * Configure PHPMailer to use SMTP.
 *
 * @param PHPMailer $phpmailer PHPMailer instance passed by reference.
 */
add_action( 'phpmailer_init', function( $phpmailer ) {
	// Bail if an SMTP host hasn't been defined.
	if ( ! defined( 'CEDARO_SMTP_HOST' ) ) {
		return;
	}

	$phpmailer->isSMTP();
	$phpmailer->Host = CEDARO_SMTP_HOST;

	// Enable SMTP authentication if username and password are defined.
	if ( defined( 'CEDARO_SMTP_USERNAME' ) && defined( 'CEDARO_SMTP_PASSWORD' ) ) {
		$phpmailer->SMTPAuth = true;
		$phpmailer->Username = CEDARO_SMTP_USERNAME;
		$phpmailer->Password = CEDARO_SMTP_PASSWORD;
	}
} );

wp-config.php

<?php
/**
 * SMTP host.
 *
 * Format: {protocol}://{host}:{port}
 *
 * The protocol and port are optional. Protocol can be 'ssl' or 'tls'.
 */
define( 'CEDARO_SMTP_HOST', 'tls://smtp.example.com:587' );

/**
 * SMTP username.
 */
//define( 'CEDARO_SMTP_USERNAME', '' );

/**
 * SMTP password.
 */
//define( 'CEDARO_SMTP_PASSWORD', '' );