Opt-out logged 2.1s after send, before anyone could open the email

Opt-out logged 2.1s after send, before anyone could open the email

An opt-out came back from an email we sent before any person could have opened it. Our records had the contact marked at 23:55:10.548 and the opt-out at 23:55:12.701, 2.1 seconds later.

Corporate mail security fetches every link in an inbound message before the recipient sees it. Microsoft Defender Safe Links and Proofpoint URL Defense both do, the unsubscribe link in the footer included. A list that drops people on a plain link fetch loses every reader behind such a gateway on delivery, and there's no error anywhere.

One-click unsubscribe rides a form submission rather than a link for exactly this reason. We rewrote both of our newsletter mail links to match. The emailed link now opens a page with a button, and only pressing that button writes.

<caption>A security scanner clicked our unsubscribe link seconds after the email landed, so now the link just opens a button.</caption>

#email