To check whether an email sent by me is read or not

Question

I am using PHP mail function to send mails to my clients. But, I wish to know how many of the recipients have actually bothered to open my mail and how many have not.

Is there any way to detect that ? Any javascript function will surely be disabled by the clients email user interface.

Any help in this regard will be appreciated

Answer 1

The most common means of accomplishing this is to send HTML email, with references to some image hosted by your web server. In each email, as part of that image's URL, include a unique identifier. Then as people read your email, and download the images, that activity will be noted in your web server logs. All you have to do then is a bit of log analysis.

Answer 2

One solution, if the person receiving the email allows remote images (often email clients will prompt for this option by default), is to display a unique image URL (either a "real" one or a 1x1 pixel) residing on a server you own. Therefore, you can track if that image URL has been loaded on your server by the client.

There are also read-receipts, but those are optional and not supported by all clients.