Gmail Annotations in 2025: What They Are, How They Work, and What Comes Next

Since launching in 2018, Gmail annotations have evolved into a key feature of Gmail’s promotions tab.  

What exactly are they?  

In simple terms, Gmail annotations are snippets of structured data that senders can add to promotional emails. Annotations enhance the visual appearance of these emails and help deliver more value to recipients. 

Annotations also let marketers highlight key information—like discounts, limited-time deals, and product images —before the email is even opened.  

In 2025, annotations are more relevant than ever.  

As inboxes get more cluttered and adoption of logo-display specifications like Brand Indicators for Message Identification (BIMI) and Verified Mark Certificates (VMCs) increases, annotations offer a unique, underused opportunity for brands to stand out in inboxes.  

Why Gmail annotations matter 

Major mailbox providers like Microsoft, Yahoo, and Gmail each have their own version of mailbox categorization. Recently, Apple’s iOS 18 introduced tabs for users using the native Mail app.  

As a result, marketers’ perspectives on mailbox categorization have changed. Gmail’s promotions tab has gone from an “email engagement graveyard” to a more dynamic and shoppable space, better curated by machine learning and user behavior.  

Gmail annotations align perfectly with this vision, giving emails a chance to feel more like valuable content and less like spam. 

With Gmail’s increased support of content previews, annotated emails offer a gateway to higher open rates, better brand recognition, and improved user engagement.  

The state of Gmail annotations in 2025 

As of June 2025, Gmail Annotations remain semi-supported and underused. Despite a lack of annotation updates from Google, usage among top-tier brands like Sephora, Domino’s, and Ubisoft has grown.  

More email service providers (ESPs) now support annotations directly in their templates, making them easier for marketers to implement without a heavy technical lift. 

However, because annotation display remains inconsistent, annotations have become more of a “nice-to-have” rather than a dependable, core campaign feature.  

Gmail annotations present a few notable challenges that both inspire adoption and hinder it.

1. Auto-generated annotations
In 2024, Google began experimenting with auto-generating annotations based on email content. While helpful for brands that haven’t adopted annotations, this presents certain risks: 

• Brand misrepresentation: Auto-generated images or CTAs might not align with a brand’s identity or the email’s core offer.  
• Inaccurate deals: Gmail might misinterpret offers or display expired promotions. 
• Inconsistent rendering: The same email might render differently for different users or devices, which may create confusion.
  

2. Limited control
Because Gmail decides when and how annotations appear, marketers can’t always rely on annotations to enhance the inbox experience. This lack of control has led some brands to deprioritize annotations, especially when consistency is critical (e.g., during major launches or campaigns). 

Types of Gmail annotations 

Wondering how annotations might fit into your email strategy? Marketers can try a variety of annotation types using different fields.  

These include: 

• Deal badges: A small tag that indicates a special offer, such as “20% off” or “Free Shipping.” 

• Single image previews: A thumbnail or banner image shown alongside your message preview. 

• Discount codes: A visible code that encourages quick action without opening the email. 

• Offer validation: Indicates how long the deal lasts, which can help create urgency—but be careful when adding annotated expiration dates. 

• CTA text: Can highlight phrases like “Shop Now” or “Get the Deal.”
  
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• Product carousels: Carousels allow multiple image previews for a promotion. Brands can include up to 10 image previews in a carousel, and each image must be unique.
  
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  Gmail’s rendering logic 

  Marketers looking to implement Gmail annotations should note that there’s an application process. Brands must apply directly with Gmail for their annotations to appear, even if the code has already been implemented in the email. Even after a sender goes through the application process and implements the annotations code, Gmail still doesn’t guarantee they will show up.  

  Gmail uses a proprietary algorithm to decide when and how to show annotations. While we don’t know Gmail’s “secret sauce,” the display algorithm may include factors like a user’s engagement history with a brand, offer relevance, and frequency or quality of past annotations.  

  Importantly, annotations are still only visible in the promotions tab and primarily in the desktop and mobile Gmail apps. Users who don’t use the promotions tab or use alternative mail clients won’t see them. 

  The future of Gmail annotations 

  As of 2025, the future of Gmail Annotations feels both promising and precarious. Google has neither sunsetted nor significantly promoted annotations in the past year. This ambiguity raises questions: will Google invest in making annotations a standardized part of email marketing, or will they phase it out? 

  One possible direction is more AI-driven dynamic annotations. Imagine Gmail creating real-time, user-personalized previews of emails—pulling in content like weather-based deals, location-specific events, or AI-curated product recommendations. This could make the inbox more engaging, but it may further reduce sender control. 

  All that said, here’s how marketers should approach annotations in 2025: 

  • Test selectively: Test annotations on high volume, but not revenue-critical campaigns (like holiday promos or product launches) where inbox presence matters and a measurable impact can be observed. Because annotations display is unpredictable, Google offers a Preview Tool for marketers to ensure the code displays accurately and appropriately.  
  • Optimize non-annotated content: Ensure your subject line and offer are strong without annotations. Treat them as a bonus, not a necessity. 
  • Stay on-message: Leverage annotations to highlight key features or deals that are appropriate to the email’s promotion to avoid confusion or frustration for your subscribers.  
  • Monitor performance: Use A/B testing and analytics to track whether annotated emails drive higher open and click-through rates for your audience. 

  Don’t over-rely on Gmail annotations   

  Gmail annotations offer an exciting glimpse into a more visual, interactive inbox—but they come with caveats around visibility and control. 

  Marketers shouldn’t fully rely on annotations—they should consider annotations part of a broader email strategy that focuses on value, clarity, and elevating your presence in subscriber inboxes.  

  As Gmail evolves, brands that succeed will find a balance between leveraging the many tools at their disposal while maintaining control over how they appear in the inbox.  

  Until Google offers clearer direction, annotations are a tool—not a guarantee. Use them wisely, monitor their impact, and be ready to adapt as they evolve. 

  Want to learn more about the latest changes from mailbox providers like Gmail? Check out our latest episode of State of Email, on-demand, featuring speakers from Gmail, Yahoo, and Microsoft.

  Watch on-demand!