Monetize your Omnisend email campaigns with open-time ads
MailAdx integrates with Omnisend custom HTML blocks and contact tags. Turn your Omnisend email broadcasts into passive ad revenue.
Why add MailAdx to Omnisend?
How to integrate MailAdx with Omnisend
- 1
Sign up for MailAdx
Create your publisher account and ad placement in the Publisher Portal.
- 2
Add a Custom Code block in Omnisend
In Omnisend's campaign editor, add a Custom Code element.
- 3
Configure contact property syntax
Use Omnisend's property syntax for the subscriber hash tag.
- 4
Test and verify
Send a test campaign to verify open-time ad rendering.
Omnisend editor tips
In Omnisend's campaign builder, add a Custom Code element. Reference your subscriber email hash using Omnisend's contact property syntax.
<!-- 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 -->Omnisend + MailAdx: common questions
How does billing work when I send through Omnisend?
You pay Omnisend for email delivery as usual. MailAdx charges only when a subscriber opens and the ad image is requested — not when Omnisend sends the email. A 10,000-recipient send with a 35% open rate generates roughly 3,500 billable impressions, not 10,000.
Can I use multiple ad placements in one Omnisend template?
Yes. Create separate ad units in MailAdx (e.g., header, mid-roll, footer) and paste each tag in a different HTML block. Each placement has its own floor CPM and reporting in the Publisher Portal.
Does the Omnisend integration work on mobile email clients?
Yes. MailAdx serves standard HTML image tags that render in Gmail iOS/Android, Apple Mail, Yahoo, and Outlook mobile. No JavaScript runs inside the inbox — the ad is a plain image request at open time.
Billing with Omnisend
MailAdx bills publishers a flat platform fee per impression served — typically $0.30–$0.50 CPM — regardless of which ESP you use. Your Omnisend subscription fee is separate; MailAdx does not charge per send or per subscriber. Advertisers pay you directly (or via programmatic demand) above the platform fee. Top up credits in the Publisher Portal before going live; impressions pause gracefully when credits reach zero.
Troubleshooting Omnisend + MailAdx
Ad image shows as broken or blank
Confirm the email-hash merge field substitutes in a real Omnisend test send — not just the editor preview. An empty hash causes MailAdx to skip the auction. Re-send a test to yourself, view the raw HTML source, and verify the eh= parameter is populated.
Impressions not appearing in Publisher Portal
Open the test email in a client that loads remote images (Gmail web, Apple Mail with images enabled). Some corporate Outlook configs block external images by default. Wait 60 seconds and refresh the portal — reporting is near-real-time.
Merge field syntax error in template
Each ESP uses different personalization syntax. Double-check you replaced {{EMAIL_SHA256}} in the MailAdx tag with Omnisend's exact variable from the setup steps above. A typo in the merge tag will break the URL at open time.
Related resources
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