Gmail caches images in emails that recipients open using its desktop Web client or its Gmail mobile apps. This caching can affect emails that contain tracking pixels or any image that can change after the recipient opens the email.
Typical Dynamic Content Request and Response
Here's a brief outline of how Monetate typically handles requests for dynamic content, including images.
- A recipient opens an email generated from a Monetate email experience.
- Monetate's servers receive data about the recipient.
- Those servers analyze the data, and then they return a dynamic image based on the targeting rules from the email experience.
- The recipient sees an image that's dynamically targeted at open time.
The illustration below depicts this process, which occurs every time an email is opened.
However, this process is slightly different for Gmail users in that the process is not repeated each time the recipient opens the email.
Dynamic Content Request and Response for Gmail Users
The first time that a recipient who uses Gmail opens the email, the request is first routed through Gmail proxy servers, which then ping Monetate's servers. Monetate then returns information based on the location of the Gmail servers, not on the recipient's location. This content is then sent to the recipient.
Gmail also caches a copy of the first image that Monetate returns to the recipient. Each subsequent time that the recipient opens the email, the image is loaded from Gmail's static cache rather than generated through a dynamic call to Monetate's servers.
Impacted Gmail Recipients
Not all recipients who use Gmail are affected by Google's image-caching policies. The chart below outlines the affected users.
| Gmail Access Point | Affected by Image Caching |
|---|---|
| Gmail desktop Web client | Yes |
| Gmail Android app | Yes |
| Gmail iOS app | Yes |
| Outlook via IMAP or POP protocol | No |
| Apple Mail via IMAP or POP protocol | No |
| Unofficial Gmail Android app | No |
| Unofficial Gmail iOS app | No |
| Any other email client or provider | No |
Impact on Personalization Clients
Gmail's image caching has a few implications for when you include impacted Gmail recipients in an email experience.
Impact on Targeting
If you select any of these options from Target based on for the experience's dynamic content, then Gmail recipients don't see the correct dynamic image:
- City
- Near Locations
- Country
- Device Platform
- Device Type
- State
- Weather
If you use select Date/Time, Query Parameter, or Products Recently Viewed, then the correct dynamic image appears the first time the Gmail recipient opens the message. However, each time they open the message thereafter, they see the same image they saw the first time—unless they opened the email using a method that isn't impacted by Gmail's image caching.
If you use a countdown timer in an experience, it ticks for 60 seconds but then stops. It doesn't restart when the Gmail recipient opens the message again unless they opened the email using a method that isn't impacted by Gmail's image caching.
If you use dynamic content that includes a Web Snap layer, the content captured by the Web Snap configuration only reflects the content available on the site at the time when the recipient first opened the message. The content captured by Web Snap doesn't change unless the Gmail recipient opens the message again unless they opened the email using a method that isn't impacted by Gmail's image caching.
Tracking
An open-time email experience displays an accurate number of initial opens for all recipients, even those affected by Gmail's image caching. Subsequent re-opens by recipients using affected Gmail clients are not tracked.
Furthermore, Monetate can still track each time a recipient clicks an image that it originally served for all recipients, including those affected by Gmail's image caching
Sending Additional Emails
You may want to send the same dynamic content to your recipient list more than once. For Gmail recipients, however, even though you sent the experience in a new email, Gmail matches the content to the original email that you sent. That means it delivers the original experience form the first time you sent the message.
Solutions for Targeting and Tracking
After you select targets for the experience's dynamic content, determine if you need special groups to provide the recipients with the most accurate targeted content. If you're concerned about caching rules for the targets that you've selected, you can edit the dynamic content eligibility settings for the experience so that Gmail recipients are ineligible for the experience. See Dynamic Content Eligibility for more information.
Solutions for Sending Additional Emails
If you want to send the same dynamic content from a previous email experience to Gmail recipients, you must include pass-through parameters. You can input this information in the modal that launches when you click GENERATE HTML.
Your email service provider (ESP) can provide you with the global pass-through parameters for sending the same content more than once.