I'd like to customize my list-unsubscribe header, and I'm wondering if I can use a URL that contains just a single pixel (aka an analytics tracking pixel)? Or, does the URL have to be accessible by someone using a browser?
Yes that is the pixel's main use, but I also could use it (with url parameters) to gather the unsubscribe data and process it in my database. If the pixel url is visited or a GET request is sent to it, it will send over the data I need to my database. However, if the pixel URL is visited via browser, it's not very user-friendly. If it's accessed solely by machine (aka google's unsubscribe server), it'll work. So that's why I'm wondering if it can be used or not. If I'm misunderstanding this, please let me know what I'm missing.