Tracking domain

A tracking domain is the hostname used in the invisible open pixel and in rewritten links inside your emails. When a reader loads the image or clicks a link, the request goes to that host, which records the event and (for links) redirects to the real destination. A custom tracking domain is a subdomain you own, pointed with a CNAME record at the tracking service and verified.

It matters because links in an email are part of how filters judge it. If your tracking runs through a host shared by thousands of other senders, your messages carry a link domain whose reputation you do not control; when someone else on that host is blocked, your mail is caught in the same net. A link domain that matches your sending domain also looks consistent to the reader who hovers over it, rather than like a redirect through a stranger’s server. The trade-off is that tracking adds a pixel and rewritten links at all, which is why some teams switch open tracking off entirely.

In Seegnals opens and clicks are tracked only through a custom tracking domain you own and verify with a CNAME. Without one, opens and clicks are simply not tracked, and the interface says so instead of showing hollow numbers.