Place the ad tag in your newsletter

The ad tag is a small block of plain HTML. When a subscriber opens the email, their mail app loads the images in the tag and MailAdx answers with the ad for that open. There is no JavaScript, and you paste it once.

Before you start

• Create an ad unit for the slot.
• Know how your email platform writes a merge tag. See Merge tags for your mailing platform.

Steps

1. Open Ad Tags.
2. Choose the slot under Ad Unit / Slot.
3. Under Open-Time Embed, find the template for your platform in 3. ESP-specific templates: Mailchimp, Klaviyo or Generic / Custom ESP. If yours isn't listed by name, use the tag in 1. Paste into your newsletter template.
4. Select Copy.
5. Replace every {{EMAIL_SHA256}} with your platform's merge tag for the subscriber's hash. Replace {{UID}} with a value that is unique per send, such as a campaign ID, or leave it blank.
6. In your email platform, open the template in HTML or code view and paste the tag where the ad should sit.
7. Send a test to yourself and open it in your mail app.

For a native slot, you can also select the code button on the slot in Ad Units. It opens the HTML Embed Snippet, where you choose your platform and copy a finished tag. For an interactive slot, the same button gives you the Get the Interactive Ad Tag code.

What happens next

Open Tag Health after your test. It shows your request and how it ended. If there is no ad for a reader, the images collapse and your layout closes up.

Your email platform's editor preview and any web copy of the newsletter don't show ads, because merge tags are only filled when the email is sent. Tag Health lists those separately and doesn't count them as problems.

To check for an eligible campaign without sending anything, open Live Test — Run a Decision on the Ad Tags page and select Run Test Decision.

If something goes wrong

• The merge tag shows as plain text in the sent email. Your platform didn't fill it. Check the syntax in Merge tags for your mailing platform.
• "204 No Content — no eligible ad found for this slot." The test ran, and no campaign is eligible for this slot right now. This is about demand, not the tag. See No ads are showing.
• The slot is marked paused. That tag shows no ad until you resume the slot in Ad Units.
• No ads after a send. Follow No ads are showing.