This feature requires MailerPress Pro.
Postmark is an email delivery service. Connect it to MailerPress to send your campaigns, automation emails and test emails through a Postmark server, and to track bounces (emails returned as undeliverable, for example because the address doesn’t exist).
1. Prepare your Postmark account
- Create an account on the Postmark website or sign in.
- Go to Servers and open the server MailerPress should use, or create a dedicated one (for example “MailerPress”).
- Open the server’s API Tokens tab and copy the Server API Token. MailerPress uses this secret token to send through your Postmark server.
- Go to Sender Signatures and add your domain. At your domain provider, add the DNS records Postmark gives you (DKIM and Return-Path): they prove you own the domain. Then verify the domain in Postmark.
While your Postmark account is pending approval, you can only send to addresses on the same domain as your sender signatures. Request account approval from the Postmark dashboard to send to any address.
2. Link your site with the Postmark API
- Go to MailerPress > Integrations and open the Email Service Providers tab.
- In Other Providers, click Configure on the PostMark card.
- Paste your Server API Token in PostMark Server API token.
- Optional: in Postmark Message Stream ID, enter the message stream MailerPress should use (a stream is a separate sending channel in Postmark), for example
broadcasts. Leave it empty to use Postmark’s default transactional stream. - Fill in Default sender email address and Default sender name. The address must use your verified Postmark domain. Empty fields show your global default sender as a placeholder.
- Click Save changes. The card moves to Configured Providers.
- Turn on the card’s Enable toggle, then click Set as primary provider. The card shows the Primary badge: only the primary provider sends your emails.
3. Send a test email
- On the PostMark card, open the Actions menu (three dots) and click Send test email.
- Enter a recipient in Send to and click Send.
You should receive an email with the subject “This is a Sending Method Test”. If the test fails, MailerPress shows the error returned by Postmark:
- 401: the Server API Token is invalid or missing.
- 403: the token doesn’t have the necessary permissions, or the Postmark account is suspended.
- 422: the email data isn’t valid. Check the sender address and its sender signature, and the Postmark Message Stream ID if you filled it in.
- 429: too many requests. Wait before trying again.
4. Configure the sending speed
- Go to MailerPress > Settings > Sending frequency, or click Adjust sending frequency on the PostMark card.
- Under Configuration Mode, choose Profile and select one of the Postmark profiles below. You can also choose Automatic to let MailerPress pick a profile, or Manual to set your own values.
- Click Save settings.
| Profile | Emails per batch | Interval | Emails per hour |
|---|---|---|---|
| Prudent (10k plan) | 50 | 5 minutes | 600 |
| Balanced (Recommended) | 75 | 5 minutes | 900 |
| Performance (100k+ plans) | 200 | 5 minutes | 2,400 |
The sending frequency is saved for the provider that is primary at that moment. Set Postmark as primary before you click Save settings. See How to change your sending frequency in MailerPress.
5. Enable bounce tracking
MailerPress learns about bounces through a webhook: a URL that Postmark calls automatically when an email bounces.
- On the PostMark card, click Configure.
- Turn on Enable bounce tracking. The setting is saved immediately.
- Under Webhook URL, click Copy. The URL looks like
https://example.com/wp-json/mailerpress/v1/esp/bounce/postmark. - In Postmark, open your server, go to Message Streams and select the stream MailerPress sends through: your default transactional stream, or the one set in Postmark Message Stream ID.
- Open the Webhooks tab and click Add webhook.
- Paste the URL in Webhook URL, check the Bounce event and save.
MailerPress marks the contact as bounced for every bounce notification from Postmark.
Leave Webhook signing secret empty. MailerPress only records a bounce if it sent an email to that address through Postmark in the last 30 days.
6. Track your bounces
Go to MailerPress > Audience and click the Bounced tab of the contact list. Campaigns only go to subscribed contacts, so bounced contacts no longer receive them.
To compare Postmark with the other sending services, see Choose and configure your email sending service.