Gmail - Largest Inbox Provider
Gmail holds over 1.8 billion active users worldwide, making it the most used email client on the planet by a significant margin. In the US alone, Gmail accounts for roughly 29% of all email opens. For eCom brands targeting everyday consumers, the number is even higher.
So if your revenue, or part of it, depends on the email marketing channel, you definitely want to optimize your strategy for the largest inbox provider today.
What Is Gemini?
Gemini is Google’s AI model, and it is becoming the backbone of how Google products think and operate. Think of it as Google’s answer to what AI should look like inside its own ecosystem – smarter search, smarter assistant, smarter inbox.
Google has been rolling Gemini into Gmail at a steady pace. What started as a summarization tool has quickly evolved into something that actively shapes how users interact with their emails. It reads emails, pulls key information, drafts replies, and helps users decide what deserves their attention and what does not.
And it is not slowing down. Our expectation, based on Google’s current roadmap and how aggressively they are integrating Gemini across all products, is that the AI layer inside Gmail will only get deeper from here.
Gmail + Gemini = New Level
When the biggest inbox platform meets one of the leading AI giants, we are seeing changes that must not go unnoticed. Two of them stand out as the most impactful for email marketers.
The AI Inbox
Gemini is now Gmail’s active curator, deciding which emails are surfaced as priorities and which are tucked into background tabs.
This goes far beyond spam filtering, it is an AI evaluating the intent and urgency of your message on behalf of the subscriber. It essentially determines the “mental real estate” your email occupies before it is even considered for an open.
AI Overviews
Gmail can now generate concise summaries of any message or thread directly in the inbox view. This means subscribers can consume your core message through an AI-generated snapshot without ever scrolling through your design.
For your metrics, this often results in lower click-through rates and weaker campaign performance, as the AI delivers the “cliff notes” and allows the user to move on.
Why This Is a Problem for eCom Email Marketing
The AI tools powering Gmail are significantly better at reading and interpreting text than they are at processing images. And most eCom email campaigns today are built almost entirely around visuals.
Back in 2020, when dark mode became a standard feature across devices and email clients, it created a real design problem for email marketers. Emails that combined text and images started looking broken, inconsistent, and unprofessional in dark mode environments. The text colors clashed, the backgrounds inverted, and the layouts fell apart.
The cleanest solution at the time was to move away from live text inside emails and go fully image-based. Using images only, you had full control over how it looks in any environment. Also, at that point, text-to-image ratio was not a major deliverability factor anymore, so there was no real downside. That decision made sense then. Fast forward to 2026, and now we have a new challenge.
When Gemini tries to summarize or evaluate one of these image-heavy emails, it has very little to work with. The result is a weak or inaccurate summary, lower prioritization scores, and a campaign that underperforms, not because your offer was bad, not because your design was off, but because the AI simply could not read what you were trying to say.
If your promotional message only lives inside a graphic, you are making Gemini work harder than it wants to. Gemini can process images, but it is built to serve Gmail users first – and that means it will consistently favor emails with clear, readable text over promotional campaigns where the message is buried inside an image.
How to optimize your Email strategy for this change
1. Rethink Your Subject Line and Preview Text Strategy
Subject lines and preview text have always been the first impression of an email. But with Gemini in the picture, that first impression now has to work on two levels – for the human and for the AI.
Mystery-based subject lines like “You won’t believe this” or “We saved this just for you” used to perform well because they triggered curiosity. That still works, but only if Gemini decides your email is worth surfacing in the first place. An AI that cannot understand what your email is about is less likely to prioritize it.
Our recommendation is to lead with clarity first, then layer in curiosity. Your subject line should give Gemini enough signal to understand the context of the email, while still giving the subscriber a reason to click. Preview text becomes even more important here, treat it as your first line of body copy, not an afterthought or addition to the subject line.
2. Rebalance Your Text-to-Image Ratio
This does not mean stripping out all visuals. It means making sure your emails have enough real, crawlable text to give AI tools something to work with. A good rule of thumb is that the core message of your email should be readable even if every image is removed.
3. Implement Text-Based Emails - But Smartly
Alt text is no longer just an accessibility feature. It is a signal to AI tools about what your images actually contain.
If your email body copy lives inside an image, use the alt text to summarize or replicate that copy. If you have a promotional banner that says “30% off all sneakers this weekend,” that exact line should be in your alt text. Give Gemini the words it needs to understand your campaign.
4. Write Descriptive Alt Text for Every Image
Going text-based does not mean going plain or boring. Text-based emails, when done well, can feel personal, direct, and high-converting. The key is to write them with the same intentionality you would bring to a designed campaign.
Strong copy, clear structure, a single focused call to action. These perform well with AI prioritization and they perform well with subscribers who have grown tired of promotional design overload.
Pro tip
We, at Retention Side, recently started testing an approach that directly addresses the AI readability problem. For our Gmail subscribers, segmented separately, we added a text block in the email footer that summarizes the full campaign in plain copy. A few sentences covering the offer, the key benefit, and the call to action – nothing fancy, just clear text.
The results are early, and several A/B tests are still running, but across all accounts, we are already seeing a 3.59% higher open rate for Gmail segments using this approach compared to the control. That is a meaningful lift, and we expect it to grow as we refine the copy approach in those summary blocks.
The takeaway is simple. Give the AI something to read, and it will work in your favor.
Conclusion
Gmail is too big to ignore, and Gemini is changing the rules of what gets seen inside it. The brands that adapt fastest will have a significant advantage in the inbox over the next 12 to 24 months.
The shift is not dramatic, it does not require rebuilding your entire strategy from scratch. But it does require paying attention to things that email marketers have been underestimating for years. The text in your emails. The alt text on your images. The clarity in your subject lines. The signals you are sending to an AI that is now sitting between you and your subscriber.
Consult with your Email Marketing experts on what is the best approach for your brand to adapt to these changes. Alternatively, seek support from experienced email marketing agencies like Retention Side.
