Mautic + MailKite

Mautic is an open-source marketing automation platform. Mautic 5+ runs on Symfony Mailer with a DSN-based transport config, so mailkite/symfony-mailer is a first-party MailKite transport — no SMTP round-trip, honest error surfacing from the API instead of a generic SMTP rejection.

What you need

• A verified domain with SPF + DKIM published
• Your API key (mk_live_…)
• Mautic 5 or later (self-hosted; requires Composer access to the install)

Recommended: the Symfony Mailer transport

Install the package alongside Mautic:

composer require mailkite/symfony-mailer

Set the Mailer DSN — either in .env.local or wherever your Mautic install reads MAILER_DSN (some hosts set this in Settings → Email Settings → Service: DSN instead):

# .env.local (or wherever Mautic reads MAILER_DSN)
MAILER_DSN=mailkite+api://mk_live_...@default

The API key goes in the DSN's user slot — no separate SMTP username to invent. Mautic autoconfigures the transport factory once the package is installed; nothing else to register.

Alternative: SMTP

If you can't install a Composer package (managed hosting, no shell access), point Mautic's SMTP transport at MailKite's relay instead:

# Settings → Email Settings → New (fallback path, no package install)

Name:               MailKite
Email Address:      hello@yourdomain.com
Service:            Other
SMTP Host:          smtp.mailkite.dev
SMTP Port:          587
SMTP Auth:          Yes
SMTP Username:      mailkite
SMTP Password:      mk_live_...
SMTP Encryption:    TLS

A note on batch sending

Symfony Mailer transports — including this one — send one email per request; Mautic's own batching/queue layer is what fans out a campaign send into individual calls. If you're calling MailKite directly outside Mautic for very high-volume sends, use the PHP SDK's sendBatch() instead of looping the transport.

Test it

Create a test email in the Mautic email editor and use the Send test button to verify the connection. Check your MailKite dashboard to confirm the message was delivered — errors now surface with MailKite's own message (e.g. "domain not verified") instead of a generic SMTP rejection.

Troubleshooting

• Emails not sending — confirm the from address is on a verified domain.
• DSN not picked up — clear Mautic's cache after changing MAILER_DSN: bin/console cache:clear.
• 535 Authentication failed (SMTP path) — your password must be your mk_live_… API key, not a separate SMTP password.

Full transport reference: Symfony Mailer transport. See the SMTP relay docs for the full connection reference, or all integrations for other platforms.