Transactional email

One-to-one product email — OTPs, password resets, receipts, alerts. Send via REST or drop-in SMTP. Sub-2-second median delivery on Gmail.

Two ways to send

Pick whichever fits your stack:

REST API — recommended for new integrations. Full payload control, structured responses, easy to log and retry.
SMTP relay — drop-in for WordPress, Drupal, any mail library. Point your existing app at smtp.mailazy.com:587 and you're sending in minutes.

Both paths share the same templates, logs, suppression list, deliverability monitoring and reputation — there is no penalty for picking one over the other.

REST API

Send by template slug (recommended)

POST /api/v1/send
{
  "to": "alice@example.com",
  "templateSlug": "password-reset",
  "variables": {
    "resetUrl": "https://app.acme.com/reset/abc123",
    "expiresIn": "10 minutes"
  }
}

Variables substitute Handlebars placeholders in the template's subject and body. Unknown placeholders render as empty strings (not as the literal {{var}}).

Send inline (one-off)

POST /api/v1/send
{
  "to": "alice@example.com",
  "subject": "Order #4729 shipped",
  "html": "<p>Your order is on the way.</p>"
}

Inline sends skip the template pipeline but still respect suppressions, write logs, and emit webhooks.

Response

200 OK
{
  "messageId": "msg_01HXAB...",
  "status":    "queued",
  "to":        "alice@example.com",
  "templateSlug": "password-reset",
  "templateVersion": 4
}

The queue typically drains within a second; track final status via webhooks or GET /api/v1/logs/{messageId}.

SMTP relay

Use any SMTP library — node-mailer, PHPMailer, Spring's JavaMailSender, etc. Point it at:

Setting	Value
Host	`smtp.mailazy.com`
Port	587 (STARTTLS) or 465 (SSL)
Username	your `X-API-Key`
Password	your `X-API-Secret`
From address	any verified domain on your account

Standard SMTP headers are honored. To trigger a saved template via SMTP, add a custom header:

X-Mailazy-Template: welcome
X-Mailazy-Variables: {"name":"Alice","plan":"pro"}

Webhooks

Subscribe to delivery events to update your database in real time. One subscription per product, one endpoint URL, fan out by event type on your side.

POST /api/v1/webhooks
{
  "url": "https://app.acme.com/mailazy/webhook",
  "events": ["delivered", "opened", "clicked", "bounced", "complained", "unsubscribed"]
}

Payload

POST https://app.acme.com/mailazy/webhook
X-Mailazy-Signature: t=1747008000,v1=<sha256-hmac>

{
  "event":     "delivered",
  "messageId": "msg_01HXAB...",
  "to":        "alice@example.com",
  "templateSlug": "password-reset",
  "timestamp": "2026-05-12T10:00:00Z",
  "data": { "smtpResponse": "250 OK" }
}

Verify the signature with HMAC-SHA256 of the raw body using your webhook secret (shown once at subscription creation). Webhooks retry with exponential backoff for 24h on any non-2xx response.

Bring your own AWS SES

On Marketing tier and up, point Mailazy at your AWS SES account. We handle reputation monitoring, warm-up and the marketing layer; you pay AWS directly for sends. Typical savings: 70–90% vs legacy ESPs at 1M+ volume.

Configure under Settings → SMTP in the dashboard. Once your SES credentials are saved and verified, all sends route through SES — REST and SMTP relay both transparently use it.

Deliverability defaults

SPF, DKIM and DMARC alignment enforced on every send. Misaligned domains return 422 at API time, not silent bounces.
Rotational DKIM — keys rotate every 90 days automatically.
Bounce filtering — hard bounces auto-suppress the recipient after one failure; soft bounces retry on managed schedule.
RFC 8058 one-click unsubscribe — the {{> unsubscribe-footer}} partial includes List-Unsubscribe-Post headers automatically.

Rate limits

Per-product limits, applied across REST + SMTP combined:

Free tier: 10 req/s, 10,000 sends/month.
Marketing tier: 100 req/s, 1,000,000 sends/month included.
Scale tier: custom, contact sales.

Exceeding returns 429 Too Many Requests with a Retry-After header. The client SDKs back off automatically.