Transactional Email lets your website or application send mail — receipts, password resets, contact-form notifications — from your own domain, delivered through Postmark's infrastructure for high deliverability.
1. Add the add-on
On your hosting plan's page, switch on Transactional Email and pick the domain(s) you want to send from. Your plan's primary domain is always included. Each sending domain gets its own isolated sending infrastructure and its own credentials.
2. Verify your domain (DNS records)
Open Transactional Email from your hosting plan. Each sending domain shows two DNS records:
| Record | Purpose |
|---|---|
TXT (DKIM) |
Cryptographically signs your mail so receivers can trust it |
CNAME (Return-Path) |
Handles bounces and improves deliverability |
Add both at your DNS provider, exactly as shown.
If your domain's DNS is managed by phas (it has a zone under DNS in your sidebar), click Auto-setup DNS on the record card and we publish both records for you — no copying required. We also add them automatically when the add-on is first set up.
We re-check every few minutes; the domain flips from Setup DNS to Active once both records are live. DNS changes can take up to an hour to propagate depending on your provider.
3. Get your credentials
On the same page, click Reveal API token + SMTP credentials. Treat these like a password — anyone holding them can send mail as your domain. Store them in a password manager, not in source control.
4a. Connect via SMTP
Works with anything that can send SMTP mail — WordPress, Laravel, Django, CRMs, form builders:
| Setting | Value |
|---|---|
| Host | smtp.postmarkapp.com |
| Port | 587 (STARTTLS) |
| Username | your Server API token |
| Password | your Server API token (same value) |
| From address | any mailbox on your verified sending domain |
For WordPress, a plugin like WP Mail SMTP with the "Other SMTP" option and the settings above is the quickest path.
4b. Connect via the API
Your token is a standard Postmark Server API token, so every Postmark API and library works as-is:
curl "https://api.postmarkapp.com/email" \
-X POST \
-H "Accept: application/json" \
-H "Content-Type: application/json" \
-H "X-Postmark-Server-Token: YOUR_SERVER_API_TOKEN" \
-d '{
"From": "[email protected]",
"To": "[email protected]",
"Subject": "Hello",
"TextBody": "It works."
}'
Postmark's official libraries (PHP, Python, Node, Ruby, .NET) take the same token. The From address must be on your verified sending domain.
Deliverability
The Transactional Email page lists recent hard bounces, soft bounces and spam complaints for each domain. Repeated hard bounces or complaints damage your sending reputation — remove those addresses from your lists promptly.
Transactional email is for mail your users expect to receive. Bulk marketing or unsolicited mail isn't permitted and will get your sending suspended — see our Acceptable Use Policy.