Impression and Click Tracking

The ad tag is an image whose URL MailAdx answers at open time. The same request that chooses the ad is the one that counts it.

Impressions

When a subscriber opens the email, their mail client requests the ad image URL (/adserver/display?pub=…&pk=…&eh=…). MailAdx runs the auction for that open and returns the winning creative's image directly in the response, marked Cache-Control: no-store. The impression is counted once the image has actually been delivered. If nothing is eligible — or the tag is missing the subscriber value — the response is a transparent 1×1 image and nothing is counted.

Gmail

Gmail fetches every email image through its own proxy, from Google's servers, on each open. Because the response is not cacheable, every open — re-opens included — reaches MailAdx and gets a fresh decision. Geography is not inferred for these requests, because the IP address is Google's.

Apple Mail Privacy Protection

Apple's privacy protection loads images on Apple servers, sometimes before anyone reads the email. MailAdx recognises these requests and labels them with device AppleMPP in reports.

Clicks

The ad is wrapped in MailAdx's click URL (/adserver/click). It records the click and redirects (HTTP 307) to the creative's destination. For leads campaigns the destination gets a signed mxcv token appended, so the advertiser's conversion tag can report sign-ups (Conversion Tracking). Clicks resolve for 30 days after the ad was shown; after that the reader sees a short “this ad has expired” page instead of the destination.

Branding images

The tag also loads a small “Ad” label, a “Powered by MailAdx” strip and an AdChoices icon. They appear only when an ad was actually shown; otherwise they collapse to transparent images.