How to Send Noptin Emails Through Postal

Noptin can send your newsletters, campaigns, and automation emails through your own Postal Mail server.

This is useful if you want Noptin emails to use Postal while the rest of your WordPress emails continue using your existing SMTP plugin or hosting mail service.

No custom code is required. You only need to install the Postal add-on and enter your Postal API credentials.

What you’ll need

Ensure you have a working Postal mail server before you begin. If you need to install one, the video below explains the process.

Step 1: Install the Postal add-on

Log in to your WordPress admin dashboard, then navigate to Noptin > Addons.

Next, click the “View all add-ons” button. Search for Postal and install the add-on.

Step 2: Create a Postal API key

Log in to your Postal dashboard and open the mail server you want to use for Noptin.

Next, create a new API credential for that server.

Finally, copy the API key.

You will paste this key into Noptin in the next step.

Step 3: Configure Postal in Noptin

In your WordPress dashboard, go to Noptin > Settings > Integrations > Postal.

Enter your Postal server domain. This is the URL where you’ve installed Postal. For example:

https://postal.example.com

Then paste your Postal API key into the API Key field and save your settings.

That’s all. Noptin will now send all your emails through your Postal server. You can pause this at any time by unchecking the “Send Noptin emails via Postal” checkbox.

Handling Bounces

Configure Postal’s bounce webhooks so Noptin can mark subscribers as bounced after a bounce or permanent delivery failure.

1. Copy the Bounce Handler URL from Noptin > Settings > Integrations > Postal.
2. In your Postal dashboard, open the mail server that Noptin uses and add a webhook with the copied URL.
3. Enable the MessageBounced and MessageDeliveryFailed events, then save the webhook.

Noptin marks affected subscribers as Bounced so they are excluded from future campaigns. Temporary delivery delays do not mark subscribers as bounced. See Postal’s webhook documentation for details about these events.

Import addresses already suppressed in Postal

Setting up the webhook does not import addresses already on Postal’s suppression list. Postal holds messages sent to suppressed addresses, so those messages may not generate another bounce notification.

Suppressed and bounced are different. A bounce means a delivery failed. Suppression means Postal is holding further messages to an address. Postal adds addresses to its suppression list after repeated hard failures or after soft-failure retries are exhausted. A suppressed address is therefore not necessarily permanently undeliverable.

Postal removes suppression entries automatically after 30 days by default, depending on your server configuration. Marking an address as Bounced in Noptin excludes it from future campaigns until its Noptin status is changed. This is a manual way to stop further campaign sends, not a matching Postal status. See Postal’s suppression-list documentation for its rules.

1. In your Postal mail server, go to Messages > Suppressions. Review the addresses and suppression reasons, then select the addresses to exclude from Noptin campaigns. Ask your Postal server administrator for help extracting the list if needed.
2. Create a CSV with email and status columns. Add only the selected addresses and set each status to bounced.
3. Open Noptin’s subscriber import screen and upload the CSV.
4. Map the email and status columns to the matching subscriber fields, then enable Update existing records.
5. Click Import. When the import finishes, confirm that the selected subscribers have the Bounced status.