AI Inbox Summary Preview
See how Gmail, Outlook and Apple Mail AI will summarise your email before your subscriber opens it. The first two lines of your email are becoming your new subject line.
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AI summaries draw from the top of your email — keep the value proposition in the first two lines.
How an AI Inbox Will See It
Enter a subject line or email body above to preview the AI summary.
How AI Summaries Work in 2026
Gmail's Gemini summaries, Outlook's Copilot and Apple Intelligence all generate a short preview of each email before a human decides whether to open it. The summary is pulled primarily from the subject line, preheader and the first lines of the email body.
This changes the rules of email copywriting: the message you used to reserve for the click-through page now needs to land in the first two lines of the email itself. If the value is buried, the AI summary will be too — and your click rate will fall even though your content is fine.
Why your email click rate might be falling in 2026 explains why AI inboxes are reshaping click behaviour.
Optimise for the AI Summary, Not Just the Subject Line
For the last two decades, email marketers treated the subject line as the single most important copy in the campaign. In 2026, the AI summary has joined it — and in many inboxes it has overtaken it. When Gemini, Copilot or Apple Intelligence condenses your email into two or three lines, that summary becomes your real first impression.
The First Two Lines Rule
AI summaries are generated from the top of the email. Lead with the value proposition, the deadline or the key fact in the opening sentence. Put the "what" before the "why," and save the pleasantries for after the summary point. A good test: can a reader who never opens the email still understand what it's about and what to do?
What Changes in Practice
Write preheader text that carries meaning rather than filler. Keep the most important information in the first two lines of the body. Use one clear call to action so the suggested-action summary is unambiguous. And measure click-to-open rate (CTOR) rather than raw CTR — it isolates how your content performs among the people who did open.