Earning beyond Substack's platform with MailAdx
Substack limits direct HTML injection in emails, but MailAdx can still monetize your Substack audience via RSS-to-email tools, cross-posting setups, or when you export your list to a secondary ESP.
Why add MailAdx to Substack?
How to integrate MailAdx with Substack
- 1
Export your Substack subscriber list
In Substack Settings → Subscribers, export your subscriber list as a CSV. This gives you your subscribers' email addresses to use with a separate ESP.
- 2
Set up a secondary ESP for ad sends
Import your Substack subscribers into a secondary ESP (Beehiiv, Mailchimp, or Klaviyo) that supports MailAdx's ad tag integration. Some publishers cross-post to a secondary ESP for their ad-supported send while keeping Substack for paid subscribers.
- 3
Connect MailAdx to your secondary ESP
Follow the MailAdx integration guide for your chosen ESP. Paste the ad tag into your template with the email hash merge field.
- 4
Set up your monetization strategy
Many publishers run two sends: a Substack-native send for paid subscribers and an ad-supported send for free subscribers via MailAdx + secondary ESP.
<!-- MailAdx ad tag — decision runs at open time -->
<a href="https://mailadx.com/api/v1/serving/click?pub=YOUR_PUB&pk=header&eh={{EMAIL_SHA256}}"
target="_blank">
<img src="https://mailadx.com/api/v1/serving/display?pub=YOUR_PUB&pk=header&eh={{EMAIL_SHA256}}&w=600&h=100"
width="600" height="100" alt="" />
</a>
<!-- Replace {{EMAIL_SHA256}} with your ESP's email hash merge tag -->Substack + MailAdx: common questions
Can I add MailAdx ads directly to Substack emails?
Substack does not allow custom HTML or third-party ad tags in email sends. The recommended approach is to export your subscriber list and use a secondary ESP for ad-supported sends, while keeping Substack for your paid content.
Is this compliant with Substack's terms?
Exporting your subscriber list and using it on another platform is permitted under Substack's terms — you own your subscriber relationships. The MailAdx integration would run entirely outside of Substack's platform.
Related resources
Ready to monetize your Substack newsletter?
Free to start. No revenue share. Direct advertiser relationships from day one.