Google annotations

Google annotations are features that can be added to email templates to enhance how emails appear in Gmail’s Promotions tab.

See also: Gmail tabs

Recent developments include:

• Product carousels: Gmail automatically selects images from the email content to display in a carousel format.
• Deal annotations: Highlight promotions based on a promo code, a short description, and an expiry date.

Both features require specific additional code in the email HTML to be eligible for display.

What you need to know

✅ Allowlist requirement

Google maintains an allowlist of approved brands who can use these features.

If you are not already on the list, you can contact the Gmail Promo Tab Outreach Team to request inclusion.

👁️ No previews

There is currently no way to preview how the annotation or carousel will look before sending.

🔮 No guarantee of display

Even if annotations are implemented correctly, Google does not guarantee that they will be shown.

🚧 Ongoing changes

Google is actively testing and adjusting how these features work, which means results can vary significantly and unexpectedly.

⏱️ Annotations must be updated for every send

The annotation content (such as promo code, description, and expiry date) must be tailored for each individual email send.

In Ometria, this means editing the master template – annotations can't be updated at the campaign or child template level.

This introduces extra work and additional risk for errors.

Our testing and findings

In our own tests, we found:

• Annotations and carousels often did not appear.
• When they did appear, results were inconsistent and unpredictable.

Because of this, annotations are currently unreliable for both testing and live campaigns.

Why don’t Google annotations always display?

Even if everything is coded correctly, there’s no guarantee that Google annotations will display.

Gmail applies a number of filters and thresholds before deciding whether to show features like product carousels or deal annotations.

📸 Image quality  

Images must be high resolution, clearly focused, and follow Google's preferred aspect ratios.

Visuals with minimal or no text perform better, and anything that isn't family-safe will likely be blocked.

👀 Visibility is limited by competition 

Gmail restricts how many annotations a user sees, so if a recipient is subscribed to multiple brands using these features, some will simply be hidden.

📈 Volume matters 

Google expects annotation-enabled emails to be part of a wider, large-scale send.

If the email isn’t going to a significant number of recipients (around 100 or more), Gmail is less likely to recognise it as a legitimate campaign and may ignore the annotations altogether.

It also expects consistency — e.g., the image URLs should be the same for everyone receiving the email.

Ometria's position

Given the lack of stability, inability to preview, inconsistent results and the additional overhead of maintaining annotation content at the master template level, we have made the decision to suspend development and support for Google annotations for the time being.

This allows us to continue focusing on delivering reliable, high-quality templates for your campaigns without the added complexity or risk.

What Are Your Options?

📬 Get notified

If you would like to be notified when we revisit or reintroduce support for Google annotations, please let your Customer Success Representative know, and we will add you to our notification list.

🛠️ Self-implementation 

If you would like to experiment independently, you are welcome to follow Google’s documentation.

Please be aware: 

• Ometria is unable to provide support or assist with implementation or troubleshooting. 
• Results may vary and testing will be unpredictable. 
• Always make sure you have made a copy of the master template before editing. 
• If you are sending multiple campaigns, the annotations will apply to all campaigns using that master template.