How We Are Addressing An Ongoing Anomaly in Email Open Count and Open Rates

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At MoEngage we believe in open and transparent communication around ongoing issues that affect our customers. This article pertains to an anomaly we’ve recently seen with email open counts and open rates.

A quick summary

In June 2021, some of MoEngage’s customers reported an anomaly in email open rates. The MoEngage team collected the feedback and dived deep to investigate. We found that email open rates were inflated because of changes made by Google on their email client, Gmail. This particular change we’re talking about relates to the way image downloading works.

We have identified a fix and have rolled it out for all of our customers. With this change, MoEngage and its customers will be able to track open rates more accurately by removing some of the erroneous open counts from campaigns created going forward.

The impact of this anomaly is different for each customer, with the error ranging from 10-20%. This means that after we fix this anomaly, your open rates for new campaigns would be lower in comparison to campaigns run earlier. But this is not a cause for concern – these rates are accurate.

A detailed overview of the anomaly

To understand this anomaly better, let’s first take a look at how MoEngage tracks email opens.

How does MoEngage track email opens?

MoEngage uses an independent “email open” event tracking mechanism using an image pixel. Our platform inserts a unique one-pixel image that gets downloaded whenever your customer opens your email. Then, MoEngage is notified of this action.

Open rates for all emails are recorded at MoEngage using this mechanism.

So, what changed?

When we diagnosed this issue, we found that some of the opens recorded were triggered by Google’s Image Proxy Server. These false “email open” events led to an unexpected spike in the open rates reported.

The Image Proxy Server is operated by Google to make messages more safe and secure by checking images in an email for known viruses or malware. This prevents customer engagement platforms such as MoEngage to track certain attributes of the “email open” event. These include the location and the device used to open the email, among others. Google’s Image Proxy only allows email service providers to know IF the email was opened.

Google Image Proxy uses a variety of user agents such as “Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)”. This contains the part “via ggpht.com GoogleImageProxy” to confirm that Google Image Proxy was used to trigger the email. Usually, this is accepted to be a genuine “email open” action.

Our investigation revealed that most of the false opens recorded on MoEngage were triggered by the IP addresses belonging to Google, but not in the general format used by the Image Proxy Server.

These opens were recorded from the user agent “Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.135 Safari/537.36 Edge/12.246 Mozilla/5.0”. This faulty user agent led to a spike in the reported email open rates.

We concluded that this faulty user agent, belonging to Google, was triggering the one-pixel image inserted by MoEngage. The trigger happened within seconds of email delivery, even before your customer opened your email!

Our investigation also revealed that a majority of the opens triggered from this faulty user agent were recorded within five seconds of email delivery. Since this isn’t an ideal user behavior and all the events were recorded from the same IP address, we concluded this to be bot-like behavior.

How is MoEngage fixing this?

MoEngage is providing a two-part solution to the problem.

Firstly, we are going to block the “email open” events recorded from the identified faulty user agent. This ensures your email campaign reports only show genuine opens by your customers and not by bots. Please note, this might lead to a slight dip in the open rates you see on the MoEngage dashboard.

Secondly, we have reason to believe that there might be other faulty user agents similar to the one we’ve identified. To tackle this, we plan to apply controls in the firewall that prevent similar bots from intervening in our tracking process and causing further anomalies.

How will you be impacted?

With this change, we will be able to track email open rates more accurately. As a MoEngage customer, you may end up seeing slightly lower email open rates on the MoEngage platform. However, please note, this does not mean your customers are now opening your emails less frequently than before. This is an accurate representation of your true email open rates.

Please note: the change in email open rate will only be visible after the fix is done on your account. For more questions around this, please feel free to get in touch with our Support team.