1,396 people got an email with no way to unsubscribe, and I didn't know until I went looking

An unsubscribe link is not a nice-to-have in a marketing email. It is the thing that keeps a list from turning into a complaint and a platform from flagging every email after it. I write my own newsletter template, and I was confident the unsubscribe link in it worked, because the placeholder for it sat right there in the html, in plain sight, every time I read the template myself.

It did not work. The placeholder rendered as an empty string once the platform sent the real email, not a working link, because of exactly where in the template it sat. One issue went out with no visible way to unsubscribe at all, to 1,396 people. I only found it after the fact, by pulling the sent campaign back from the platform and reading the actual html it delivered, not the template I had written.

The template looked right because a placeholder sitting in plain text, on its own line, is exactly what I would expect a working link to look like if I were skimming it. What it needed was to sit inside an actual link tag, wrapped the same way any other link on the page is, so the platform had an address to attach the real unsubscribe url to. Outside that wrapper, the platform has nothing to attach it to and silently writes nothing back.

The send job now reads its own finished output before it goes anywhere and refuses to send if that link is missing from it. Not a warning. A hard stop.

Looking right and working right are two different checks, and the first one is the one that is easy to mistake for the second. If anything in your business sends something to a list of real people on its own, the question worth asking is whether anyone has actually opened what it sent and read it the way a stranger would, rather than the template that produced it.