Add newsletter ad revenue to your ConvertKit broadcasts
MailAdx integrates with ConvertKit (now rebranded as Kit) via custom HTML in broadcast templates. Use the subscriber email liquid tag as your hash source for open-time ad serving.
Why add MailAdx to ConvertKit (Kit)?
How to integrate MailAdx with ConvertKit (Kit)
- 1
Create your MailAdx account and ad placement
Sign up and create a publisher ad unit with your desired floor CPM and format.
- 2
Use ConvertKit's subscriber email variable
ConvertKit's liquid syntax for subscriber email is {{ subscriber.email_address }}. For the SHA-256 hash, you'll need to store a pre-computed property or use ConvertKit's API to add a custom field with the hashed value.
- 3
Add an HTML block to your broadcast template
In ConvertKit's broadcast editor, add a custom HTML block and paste the MailAdx ad tag. Replace the hash placeholder with your ConvertKit subscriber hash variable.
- 4
Test and go live
Send a test broadcast to yourself. Open the email and confirm the ad renders. Verify the impression appears in your Publisher Portal.
ConvertKit (Kit) editor tips
In Kit (ConvertKit), open any broadcast or sequence email, click the '+' to add a 'Custom HTML' content block, and paste the tag. Kit strips some inline styles on paste — the MailAdx tag uses table-safe markup that survives Kit's sanitizer.
<!-- 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 -->ConvertKit (Kit) + MailAdx: common questions
Does the ConvertKit integration work with sequences and automations?
Yes. The MailAdx ad tag is a static HTML image element that works in any email type — broadcasts, sequences, and automation emails. The open-time decision happens when the subscriber opens, regardless of how the email was triggered.
How does billing work when I send through ConvertKit (Kit)?
You pay ConvertKit (Kit) for email delivery as usual. MailAdx charges only when a subscriber opens and the ad image is requested — not when ConvertKit (Kit) 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 ConvertKit (Kit) 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 ConvertKit (Kit) 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 ConvertKit (Kit)
MailAdx bills publishers a flat platform fee per impression served — typically $0.30–$0.50 CPM — regardless of which ESP you use. Your ConvertKit (Kit) 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 ConvertKit (Kit) + MailAdx
Ad image shows as broken or blank
Confirm the email-hash merge field substitutes in a real ConvertKit (Kit) 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 ConvertKit (Kit)'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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