AI tips for email marketers
AI email summaries: The new rules for email preview text
Last Updated: 2 September 2026
Generative AI is turning up in the places marketers care about most: the inbox.
Apple Mail and Android email experiences are starting to summarise messages automatically, with real implications for how your campaigns are previewed, understood, and acted on.
The big shift isn’t that people will suddenly read long AI-generated digests of your newsletters.
The shift is that AI summaries can replace (or compete with) the snippet of text you used to control the preview that sits under the subject line.
First: how widely available is this, really?
Right now, AI email summaries are mostly available on newer devices with sufficient on-device processing power. That means the impact will be uneven in the short term.
But over the next few years, as phones are replaced, AI summaries will reach a much larger share of your list. In other words, you don’t need to panic, but you do need to start designing with this in mind.
Pre-open summaries
Figure 1.0 | Apple iPhone
iPhone users can display up to five rows of preview text without opening an email. In this example, Apple AI Summaries are in use.
Post-open summary
Figure 2.0 | Apple iPhone
iPhone users can use the Summarise button once they open the email to generate a an AI summary of the message.
Summaries
Figure 3.0 | Apple iPhone
In this example, I wrote the email shown above, and the summary is pretty much on the mark. Personally, I rarely use this feature.
Two types of AI summaries (and why one matters more)
There are two places AI summaries can show up:
- Pre-open summaries (in the inbox list – see figure 1.0). These appear before someone opens your email. In many cases, they effectively replace the preview text marketers have relied on for years.
- Post-open summaries (inside the email). These appear after the email is opened, usually behind a tap/click (“Summarise this email”). Because they’re optional, they’re likely to be used less often.
From a marketing perspective, pre-open summaries are the bigger deal. They’re visible at the decision point: “Do I open this?”
What AI summaries change in practical terms
For years, marketers have treated the subject line + preview text as a paired message. You could write a slightly mysterious subject line, then use the preview text to clarify the benefit or deliver the punchline.
AI summaries disrupt that.
If a device generates its own summary, you lose control over what appears under the subject line, and that makes “clever but vague” subject lines riskier. If the AI summary is awkward, overly literal, or pulls the wrong detail, it can also reduce opens even when your email is strong.
Design & build choices that affect AI summaries
Based on current behaviour across major inbox environments, here’s what’s most likely to influence what an AI summary produces.
Should emails be image-heavy?
AI can ignore your message entirely
If your email is largely one big image (or relies heavily on graphical text), AI may have very little usable content to work with.
That can lead to:
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“Too short to summarise” style messages
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Summaries that focus on boilerplate (footer, unsubscribe, contact details)
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Summaries that miss the actual offer or call to action
This is the same reason image-only emails have been a bad idea for years: accessibility, images-off scenarios, and performance. AI summaries add another reason: no live text = no meaningful summary.
How important are email subject lines?
Keep them descriptive, but assume they won’t always be used
You should already be writing clear subject lines. With AI summaries in play, it’s even more important, but also worth noting that some AI engines may not incorporate the subject line into the summary.
That means your opening lines of body copy matter more than ever.
Is Alt-text important in email marketing?
Yes, helpful for accessibility, but don’t expect it to drive summaries
Alt text is still essential for inclusive design. But AI summaries may ignore alt text entirely, or use it only when there isn’t enough live HTML text.
So: keep writing good alt text, just don’t treat it as your “backup copy” for AI.
Is email preheader text important?
It still matters, but behaviour can be inconsistent
Some environments treat preheader text as normal body copy and may pull heavily from it. Others may ignore it or use it unpredictably.
The takeaway: write preheader text as if it might become the summary, but don’t rely on it as the only place you explain the value.
How should I rank my email content?
Position can matter more than headings and font size
AI summaries don’t necessarily “understand” your visual hierarchy the way a human does. Heading levels and font sizes may not significantly affect the summary.
What can matter is content order, especially for short, pre-open summaries. If your most important message is buried, the AI may never surface it.
What we recommend (practical steps you can take now)
You don’t need to redesign everything overnight. But you should start adapting your email content and build standards so you’re not caught out as AI summaries become more common.
Tip 1: Put the value early, in live HTML text
Aim to make the first 1–2 lines of body copy do real work:
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Who is this for?
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What’s the benefit?
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What should they do next?
If you’re running marketing automation platforms, this is a good time to review your templates and modules to ensure they encourage strong “above the fold” live text.
Tip 2: Reduce reliance on the subject + preheader “joke/clarification” combination
If your subject line needs the preview text to make sense, you’re increasing the risk that AI will summarise it poorly.
Keep the creativity, just make sure the subject line can stand on its own.
Tip 3: Treat accessibility as a performance lever, not a compliance task
Accessible email practices (semantic structure, meaningful link text, sensible reading order, alt text) don’t just help a subset of users; they make your content more machine-readable too.
Tip 4: Stop using image-only layouts for core messages
Use images to support the message, not to carry it. Ensure:
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Key offer/value is in live text
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CTAs are real buttons/links (not baked into images)
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The email is readable with images off
Tip 5: Test across devices and measure over multiple campaigns
AI summaries will vary by device, OS version, and settings. Don’t overreact to one campaign.
Instead:
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Test representative emails across iOS and Android
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Track changes over time (opens, click-to-open, engagement by device)
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Look for cumulative effects, not one-off anomalies
Final thoughts
AI summaries are another step in a long-running trend: inbox providers taking more control over how your email is presented.
The upside is that the same fundamentals still win: clear copy, accessible builds, and strong message hierarchy.
If you design for humans and for machine readability, you’ll be in a better position as AI-driven inbox experiences become the norm.
Want a second set of eyes on your templates?
If you’d like, we can review a handful of your core email templates and campaigns and offer practical changes to improve accessibility, clarity above the fold, and resilience against AI-generated summaries, without making your emails feel generic.
Frequently Asked Questions
- Put the core value in the first 1–2 lines of live (selectable) text
- Don’t rely on subject + preheader combos to make the message understandable
- Avoid image-only layouts for key messages and CTAs
- Use accessibility best practices (reading order, meaningful links, sensible structure)
- Test across iOS and Android and measure the impact on multiple campaigns
