Send via SMTP relay

If your application already speaks SMTP (WordPress, Laravel, legacy systems, CRMs), you can send through Mailercloud without integrating the HTTP API — just point your SMTP settings at the relay.

Connection settings

Setting	Value
Host	`smtp-relay.mailercloud.com`
Ports	`587`, `2525`, or `465`
Authentication	`AUTH PLAIN` — username + password

Credentials

Switch to the Transactional Email platform (toggle in the sidebar), then open Settings → SMTP Configuration to view your host, username, and password. Use Generate new password to create or rotate the password.

Generating a new password invalidates the previous one immediately — update all systems using the old credentials.

Tracking headers

Control tracking per message with custom SMTP headers:

Header	Purpose
`mld-track-opens`	`true`/`false` — enable or disable open tracking
`mld-track-inbox`	`true`/`false` — enable inbox-placement tracking
`mld-track-campaign-id`	Group sends under a campaign ID for reporting

Security & delivery extras

IP Allowed List — restrict which IP addresses may send through your account (single IPs, ranges, or wildcards). If unset, all IPs are allowed.
Webhooks — receive real-time events for transactional sends: Sent, Delivery, Bounce, Spam, Open. See Set up webhooks.

Example (Laravel `.env`)

MAIL_MAILER=smtp
MAIL_HOST=smtp-relay.mailercloud.com
MAIL_PORT=587
MAIL_USERNAME=your-smtp-username
MAIL_PASSWORD=your-smtp-password
MAIL_FROM_ADDRESS=orders@yourdomain.com

SMTP vs HTTP API — which to use?

	SMTP relay	HTTP Email API
Setup	Config change only	Small code integration
Per-recipient personalization (mail merge)	❌ Not supported	✅ `/email-api`
Best for	Existing apps, CMS plugins, quick migration	New integrations, personalization, richer control

The sender domain must be verified on your account in either case.

Getting Started

Guides

Connection settings

Credentials

Tracking headers

Security & delivery extras

Example (Laravel `.env`)

SMTP vs HTTP API — which to use?

​Connection settings

​Credentials

​Tracking headers

​Security & delivery extras

​Example (Laravel .env)

​SMTP vs HTTP API — which to use?

Connection settings

Credentials

Tracking headers

Security & delivery extras

Example (Laravel `.env`)

SMTP vs HTTP API — which to use?