Lately, we noticed that the way Google is handling the emails is creating confusion regarding the tracking for the opens.
A little background on email tracking
The email tracker system places an invisible tracking pixel inside each message. Despite being practically invisible for people, this pixel is recognised as an image by the email client.
When rendering the message (upon opening it), the system will call the server where the “image” is stored. This action serves as a trigger for email open and will be saved to the system.
Google’s way of handling images
Google opens all images using its proxy server. Before forwarding the email to the recipient, the server loads the email content which the tracking software views as an email open. As a result, it can trigger false positive results. In addition to that, Gmail proxy server provides false information on the recipient location and device. That is why it is practically impossible to get accurate email tracking metrics if the recipient uses Gmail.
What we learnt
What we found was that Google will use its caching server most likely if the email is opened from the web browser using the Google mail interface (Google image proxy server). Even if the receiver was the one that opens the email, we will not be able to get its real IP and User Agent.
Another situation was when the email was opened as stated above, and the Google Anti-Spam Checker was hit. In this case the open will look something like:
It will have a another IP that belongs to Google (google anti-spam server ip) and the user agent is showing is fake.
On the other hand, if the email is opened with an email client, the correct IP and User Agent of the opener will be the correct ones.
Mailwizz is handling correctly these situations by avoiding the caching and counting correctly the opens. The problem is that we cannot relay on the information about the IP and User agent.
There will be a follow up, mode detailed blog article regarding the tracking here