Getting notification that an email was opened.


Add Header to email:

Disposition-Notification-To: you@yourdomain.com

As mentioned above it's not reliable and it's better to do something like this:

<img src="http://yourdomain.com/emailreceipt.php?receipt=<email of receiver>" />

And log it in a database, although again this is restricted by the email client's ability to show images and sometimes it may even put the mail into junk because it doesn't detect an image... a workaround that would be to actually outputting an image (say your logo) at the end of that script.

Edit: A quick lookup at the phpmailer class gave me the following:

$mail->ConfirmReadingTo = 'yourown@emailaddress.com';

but it's the same as the Disposition-Notification-To method above.







Send a beacon image in the emails like so

<img src='http://www.yourserver.com/beacon.php?email_id=$email_id&email_address=$user_address' style='width:1px;height:1px'>

And then use the beacon.php file to log the data. You will then want to output a 1X1 image with appropriate headers.

Important note
Many popular email clients (such as Gmail) now block external images, so this is by far, not fool proof.




// HTML

<img src="http://mydomain.com/emails/record.php?e=email@address.com" alt="Tracker" />

// (inside "record.php")
header('Content-Type: image/gif');

if(isset($_GET['e']))
{
	//validate and record click-through here
}
	
//push out image
if(ini_get('zlib.output_compression')) { ini_set('zlib.output_compression', 'Off');	}
header('Pragma: public'); 	// required
header('Expires: 0');		// no cache
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Cache-Control: private',false);
header('Content-Disposition: attachment; filename="blank.gif"');
header('Content-Transfer-Encoding: binary');
header('Content-Length: '.filesize('blank.gif'));	// provide file size
readfile('blank.gif');		// push it out
exit();


// from another article--> make if a gif
$im=imagecreatetruecolor(1,1);       // initialising the image object and asigning its simensions
$white=imagecolorallocate($im,255,255,255); // creating the color object for white color
imagefilledrectangle($im,0,0,1,1,$white); // creating a white rectangle to the image object
header("content-type: image/jpeg"); // creating an image header for returning an image to the src
imagejpeg($im); // image is being created


 Please dont do this for public facing services. This is almost 100% considered "questionable" activity in email. Many applications will block this behaviour directly, and many scanning applications will look for images that cannot be seen by the user (0,0 size, 100% transparent, etc) –  GrayWizardx Jan 7 '10 at 18:51
1 	 
	
I agree with GrayWizard, it's better to include a real image in the email, like a logo, and send the unique ID inside the url like <img src="blah.com/logo.php?id=1234">; and that url spits out the mime header & binary data for an actual image, not a HTML page.