Integrate MailAdx with Constant Contact newsletters
Constant Contact supports custom HTML code blocks in email templates. Add MailAdx's open-time ad tag to monetize your Constant Contact newsletter audience with programmatic and direct-sold demand.
Why add MailAdx to Constant Contact?
How to integrate MailAdx with Constant Contact
- 1
Create a MailAdx publisher account
Sign up and set up your ad placements in the Publisher Portal.
- 2
Add a Code block in Constant Contact
In the Constant Contact email builder, drag a Code block into your template where the ad should appear.
- 3
Configure subscriber personalization
Constant Contact uses [contact field] syntax for personalization. Set up a custom field for the SHA-256 email hash and reference it in the ad tag.
- 4
Test and activate
Send a test email, confirm the ad loads on open, and publish your template.
Constant Contact editor tips
Constant Contact's third-generation editor uses a 'Code' block from the building blocks panel. Legacy editor users should switch to the Code element in the left sidebar. Test with a real contact record, not the generic preview.
<!-- 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 -->Constant Contact + MailAdx: common questions
How does billing work when I send through Constant Contact?
You pay Constant Contact for email delivery as usual. MailAdx charges only when a subscriber opens and the ad image is requested — not when Constant Contact 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 Constant Contact 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 Constant Contact 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 Constant Contact
MailAdx bills publishers a flat platform fee per impression served — typically $0.30–$0.50 CPM — regardless of which ESP you use. Your Constant Contact 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 Constant Contact + MailAdx
Ad image shows as broken or blank
Confirm the email-hash merge field substitutes in a real Constant Contact 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 Constant Contact'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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