All integrations WordPress

WordPress + MailKite

WordPress powers 43%+ of the web. Point it at MailKite and every notification, password reset, and form submission goes out over your own DKIM-signed domain — no SMTP plugin fees, no third-party email service.

What you need

A verified domain with SPF + DKIM published
Your API key (mk_live_…)
WP Mail SMTP plugin (free, 4M+ installs) — or direct PHPMailer config

Option A: WP Mail SMTP plugin (recommended)

Install and activate WP Mail SMTP. Go to WP Mail SMTP → Settings and configure:

From Email	`hello@yourdomain.com` (on a verified domain)
From Name	Your site name
Mailer	Other SMTP
SMTP Host	`smtp.mailkite.dev`
Encryption	TLS
SMTP Port	`587`
SMTP Username	`mailkite`
SMTP Password	Your API key (`mk_live_…`)

Or add these constants to wp-config.php to skip the UI:

wp-config.php

// wp-config.php — or paste into WP Mail SMTP settings UI
define('WPMAILSMTP_MAILER', 'other');
define('WPMAILSMTP_HOST', 'smtp.mailkite.dev');
define('WPMAILSMTP_PORT', '587');
define('WPMAILSMTP_ENCRYPTION', 'tls');
define('WPMAILSMTP_USERNAME', 'mailkite');
define('WPMAILSMTP_PASSWORD', 'mk_live_...');
define('WPMAILSMTP_FROM_EMAIL', 'hello@yourdomain.com');
define('WPMAILSMTP_FROM_NAME', 'Your Site');
define('WPMAILSMTP_SET_RETURNPATH', 'false');

Option B: PHPMailer directly

If you prefer not to use a plugin, hook PHPMailer in functions.php:

functions.php

// functions.php — for sites that bypass WP Mail SMTP
add_action('phpmailer_init', function ($phpmailer) {
    $phpmailer->isSMTP();
    $phpmailer->Host       = 'smtp.mailkite.dev';
    $phpmailer->Port       = '587';
    $phpmailer->SMTPSecure = 'tls';
    $phpmailer->Username   = 'mailkite';
    $phpmailer->Password   = getenv('MK_API_KEY');
    $phpmailer->setFrom('hello@yourdomain.com', 'Your Site');
});

// Also force wp_mail to use PHPMailer's SMTP config
add_filter('wp_mail_smtp_use_phpmailer', '__return_true');

.env

# .env (or wp-config.php via getenv)
MK_API_KEY=mk_live_your_key_here
MK_WEBHOOK_SECRET=your_webhook_secret

Test it

WP Mail SMTP has a built-in Email Test tab. Or use WP-CLI:

terminal

wp eval 'mail("you@yourdomain.com", "Test from MailKite", "It works!");'

Receive inbound email (optional)

MailKite can also receive email at any address on your domain and POST it to a webhook. If you want WordPress to process inbound email — for example, to create posts from email or power a support inbox — create a webhook endpoint:

webhook.php

<?php
// wp-content/themes/your-theme/webhook.php
// Inbound email webhook handler for MailKite

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    http_response_code(405);
    exit;
}

$payload = json_decode(file_get_contents('php://input'), true);

// Verify signature
$sig     = $_SERVER['HTTP_X_MAILKITE_SIGNATURE'] ?? '';
$secret  = getenv('MK_WEBHOOK_SECRET');
$computed = hash_hmac('sha256', json_encode($payload), $secret);
if (!hash_equals($computed, $sig)) {
    http_response_code(401);
    exit;
}

$from    = $payload['from'];
$subject = $payload['subject'];
$text    = $payload['text'];

// Route to a form, support system, or post type
// Example: create a custom post type or log to a file
error_log("MailKite inbound: {$from} — {$subject}");

http_response_code(200);
echo '{"ok":true}';

Point your domain's webhook to this file and you'll receive parsed inbound email as clean JSON. See Inbound webhooks for the full payload and signature verification.

Troubleshooting

Emails not sending — confirm the From address is on a verified domain. Check WP Mail SMTP → Tools → Email Test.
535 Authentication failed — your password must be your mk_live_… API key, not a separate SMTP password.
Delayed delivery — WordPress cron (wp-cron.php) runs on page loads. For time-critical email, disable DISABLE_WP_CRON and use a real cron job.
Plugin conflicts — WP Mail SMTP overrides wp_mail(). If another plugin (e.g. WP HTML Mail) also hooks wp_mail, one may win. Deactivate alternatives.

See the SMTP relay docs for the full connection reference, or all integrations for other platforms.