How can I check if an email has been opened?

Question

I'm looking for a reliable way to check if a user has opened an email that I sent him. I know that I can use some images generated by the PHP script (and save the client headers / data on the server side), but my question is this reliable? Some web clients have images disabled by default, I'm not sure about proxies, BlackBerry, etc.

So - Are there any good and reliable solutions to this problem?

Thanks.

Answer 1

There is no reliable solution (and I'm glad not). If a user views your mail only as text, then nothing (except the mail itself) is downloaded or something like that.

Answer 2

The only solution, unfortunately, does not exist. Some email providers use a tracking pixel, some use an external css file, some track images + clicks, some track the request for any image in the email, some even try to include nifty , such as bgsound . And some do it all together.

The only ones who can report real open rates are those who have direct access to users' inboxes: the Internet service providers themselves and software providers who develop applications and plugins for gmail, outlook and co. Some of them report real open bets for marketers. Like Mail.ru , OtherInbox, and eDataSource . But for obvious reasons, all this is also not ideal.