All integrations Drupal

Drupal + MailKite

Drupal uses PHP's mail() function by default, which is unreliable for transactional email. The SMTP Authentication module routes all site email through MailKite — DKIM-signed, deliverable, and logged.

What you need

A verified domain with SPF + DKIM published
Your API key (mk_live_…)
Drupal 9+ with Composer

Install the SMTP module

terminal

# Install the SMTP module
composer require drupal/smtp
drush en smtp -y

# Configure via Drush (optional)
drush config-set smtp.settings smtp_on TRUE -y
drush config-set smtp.settings smtp_host smtp.mailkite.dev -y
drush config-set smtp.settings smtp_port 587 -y
drush config-set smtp.settings smtp_protocol tls -y
drush config-set smtp.settings smtp_username mailkite -y
drush config-set smtp.settings smtp_password "mk_live_..." -y

Configure via admin UI

Go to Configuration → System → SMTP Authentication and fill in:

SMTP Authentication settings

# Drupal SMTP Authentication module settings
# Admin → Configuration → System → SMTP Authentication
SMTP server:      smtp.mailkite.dev
SMTP port:        587
Use encrypted protocol: Yes (STARTTLS)
SMTP username:    mailkite
SMTP password:    mk_live_...
From address:      notifications@yourdomain.com
From name:         Your Drupal Site
Turn this module on: Yes

Configure via settings.php

For code-managed configuration (recommended for teams), add to settings.php or a settings override:

sites/default/settings.php

// settings.php — for configuration management / code-based setup
$config['smtp.settings']['smtp_on'] = TRUE;
$config['smtp.settings']['smtp_host'] = 'smtp.mailkite.dev';
$config['smtp.settings']['smtp_port'] = '587';
$config['smtp.settings']['smtp_protocol'] = 'tls';
$config['smtp.settings']['smtp_username'] = 'mailkite';
$config['smtp.settings']['smtp_password'] = 'mk_live_...';
$config['smtp.settings']['smtp_from'] = 'notifications@yourdomain.com';
$config['smtp.settings']['smtp_fromname'] = 'Your Drupal Site';

What gets sent through MailKite

User registration — account creation and verification emails
Password resets — "reset your password" links
Content notifications — comment alerts, content updates
Contact form submissions — messages from Drupal's contact form
Module-generated email — any module that calls drupal_mail()

Receive inbound email

For inbound email (e.g., creating content from email), create a custom module with a webhook controller:

mailkite_inbound module

<?php
// Drupal custom module: receive inbound email via MailKite webhook
// File: web/modules/custom/mailkite_inbound/mailkite_inbound.routing.yml

mailkite_inbound.receive:
  path: '/webhooks/mailkite'
  defaults:
    _controller: '\Drupal\mailkite_inbound\Controller\InboundController::handle'
  requirements:
    _access: 'TRUE'
  methods: [POST]

// File: web/modules/custom/mailkite_inbound/src/Controller/InboundController.php

namespace Drupal\mailkite_inbound\Controller;

use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\HttpFoundation\Request;

class InboundController {

  public function handle(Request $request) {
    $payload = json_decode($request->getContent(), TRUE);

    // Verify signature
    $sig     = $request->server->get('HTTP_X_MAILKITE_SIGNATURE');
    $secret  = \Drupal::config('mailkite_inbound.settings')->get('webhook_secret');
    $computed = hash_hmac('sha256', json_encode($payload), $secret);

    if (!hash_equals($computed, $sig)) {
      return new JsonResponse(['error' => 'invalid signature'], 401);
    }

    // Process: create a node, log, or trigger a reaction
    \Drupal::logger('mailkite_inbound')->notice(
      'Inbound email from @from: @subject',
      ['@from' => $payload['from'], '@subject' => $payload['subject']]
    );

    return new JsonResponse(['ok' => TRUE]);
  }
}

Troubleshooting

Module not found — run composer require drupal/smtp then drush en smtp. The module isn't in Drupal core.
Emails going to spam — the From address must be on a verified domain. Drupal defaults to site@yoursite.com which may not pass our checks.
535 Authentication failed — the password must be your mk_live_… API key, not a Drupal user credential.
PHP mail() still used — ensure the SMTP module is enabled and the "Turn this module on" setting is checked. The module overrides drupal_mail() only when active.

See the SMTP relay docs for the full connection reference, or Send API for building custom Drupal modules.