Ad caching in email and how this effects GAM integrated publishers

May 2022 changes to ad caching

Jeeng is now caching ads served to a user for 24 hours from 1st load of the unique email message as our default setting.

This has been implemented to ensure the best results possible for advertisers, end users and publishers.

  • Jeeng locks in the ad served to the user based on the 1ST LOAD of the email for 24 hours 
  • The user may open that same email on multiple devices and the same ad will appear for that 24 hours.
  • If the user refreshes the email, or opens again on another device, AFTER 24 hours from the 1st load, our ad server will refresh the ad if a new ad is available.


Subscriber, Daniel, has an iPhone with apple privacy enabled and his device plugged in overnight and is connected to wifi.  Daniel uses the apple mail device on his iPhone and views his emails on gmail in the chrome browser on his laptop. He also has an iPad he uses from time to time (also with apple privacy settings enabled)

  • Super Cool Newsletter is sent out daily at 6:00 AM to all users.
  • Daniel’s apple device loads the content of the email at 6:05 AM but Daniel has not seen the content yet.
    Jeeng serves an ad as defined by your GAM account for your direct-sold to Daniel at 6:05 AM (this is the cache for 24 hours)
  • At 8:30 AM, Daniel opens his apple mail app and reads the Super Cool Newsletter and sees the ad that loaded at 6:05AM.
  • At 9:30 AM, Daniel opens the same newsletter in GMAIL on his laptop in the browser.
    The same content will be viewable.
  • At 10:00 PM, Daniel opens the same email on his tablet. The same ad will be seen again.
    Jeeng has cached the ad experience across devices for Daniel.
  • At 7:00 AM the NEXT day, Daniel refreshes the same email.  Jeeng will look to see if a new creative should be served (based on your GAM settings) and if so, will serve new creative at that time.

Upon request - this setting can be changed by publisher account or specific newsletter.

Lowering the cache window could lead to a mismatch of the image of the ad viewed by the email viewer to the landing page they are directed to and is only advised to support specific customer use cases)

Please read on for more information as to why this change was made as well as considerations for you and your direct-sold advertisers.

As you may know, the email landscape has changed in the past 9 months.

Over 80% of emails are filtered via proxies and therefore signals that used to be dependable years ago, are no longer trustworthy.

Most notably is Apple Privacy and Apple Proxy for Apple Mail.

You likely have noticed your open rates have skyrocketed since September of 2021.

This is due to Apple loading all images in their apple mail application as a pre-load and caching those images and links.

If an iPhone with apple privacy enabled is charging and on wifi, apple will pre-load the content of the emails sent to that person, even without them taking any action to load their email.

Apple does not necessarily refresh the cached image at a “real” user open.  They “could’ but they are opaque in this.  

Jeeng is seeing approximately 70% of ad loads happening from apple devices.

This also has skewed CTR (click through rate metrics):

As an example:

If you sent 1000 emails
Apple users are 500 and non-apple users are 500
Your ESP reports a 60% open rate and you are thrilled!
But in reality
The apple users record 500 opens (100%)
The non apple users have 100 Opens (20%)
The apple opens are not accurately reported (due to the pre-loads)
In reality, your “true” open rate is closer to 20% than 60%

Jeeng serves an ad when we get that open event: And we also have seen 3 to 5x the number of impressions served to an apple privacy user to gain a click.
As such we have adjusted our algorithms to account for this new behavior and worked with the advertisers in our network to optimize their campaigns to account for this change in reported CTRs.

We are seeing the click-through numbers remain stable while impression counts have increased.

Prior to us implementing this cache change, enough for Jeeng to take notice, was a drop in post-click conversions.

We have identified that if Jeeng is to serve a new ad refresh at EVERY load, apple privacy does not respect the new load, and serves the older ad image.  In these cases, if the user clicks on the image that is from the cache, the link goes to the landing page for the newest ad. 

This behavior is what we are solving for by setting the 24-hour cache.

Jeeng aims to ensure every click lands where the user intended.

Advertiser and user satisfaction are paramount to us and ensuring that when a click occurs it routes to the correct landing page.

If your direct-sold business requirements have other mitigating factors that the 24-hour cache is in conflict with, don’t worry, Jeeng has alternatives to discuss with you and your unique business needs.

Contact us at  to discuss specific adjustments to your cache settings that may be available to balance your expectations and the realities we all face due to the pre-load changes the industry now has to embrace as the new normal.

Please ensure your Jeeng ad tags include a Send ID.

This is a variable that lets Jeeng know the difference between each deployment you make to your list.

If you send to your list multiple times a day, the Send ID ensures we can see the difference between a reload of the same email and a new load for a new deployment.

If you are not sure if you have a send ID included in your tags, please contact and we can help investigate.