Gmail and Apple Mail now summarise and prioritise some messages before a person reads them, with Gmail's features launching in the US first. Emails that state the point in the first lines, use descriptive subject lines, go to an engaged list and meet the sender rules are the ones that still get read.
Write every email so that a machine summary of it would still make someone act: put the offer, the date and the one link in the first two lines, use a subject line that describes rather than teases, give each email one job, and send only to people who engage. Gmail and Apple Mail now summarise and prioritise some mail before a person reads it, and these habits are what survive that filter.
The shift is real but uneven. Apple Intelligence has shown email summaries in the iPhone inbox since October 2024 and has supported English (India) since March 2025. Google began rolling out free AI summaries of long Gmail threads in January 2026, and on 19 May it started extending AI Inbox, a view that picks out what deserves attention, to more paying subscribers. Both Gmail changes began in the US, but the sender rules below apply to everyone now.
- Gmail users, by Google's count in January 2026
- 3 billion
- Gmail users, by Google's count in January 2026
- Spam complaint rate Gmail and Yahoo tell senders never to reach
- 0.3%
- Spam complaint rate Gmail and Yahoo tell senders never to reach
- Time Gmail suggests for honouring an unsubscribe request
- 48 hrs
- Time Gmail suggests for honouring an unsubscribe request
- Messages a day to personal Gmail accounts that make you a bulk sender
- 5,000
- Messages a day to personal Gmail accounts that make you a bulk sender
01
What the AI layer does today
Three changes matter for senders. The first is summaries. On iPhones with Apple Intelligence, Mail can show a summary in the inbox list without the message being opened. In the Gmail app, Gemini summary cards have appeared at the top of some English emails and threads since May 2025 for paid Workspace and Google One AI Premium users, and Google's January 2026 update brought thread summaries to everyone in the US at no cost.
The second is prioritisation. Apple's Priority Messages section puts the emails it judges most urgent at the top of the inbox. Google says AI Inbox spots important people from signals such as who you email often and who is in your contacts, and highlights urgent items, such as a bill due tomorrow. At I/O in May, Google added personalised draft replies and announced Gmail Live, for questioning your inbox by voice, due this summer for paying subscribers.
The third is sorting inside Promotions. In September 2025 Google said Gmail users on mobile would be able to sort promotional email by most relevant, favouring the senders and brands they engage with most, and that Gmail would surface upcoming deals and timely offers as nudges.
AI Inbox is like having a personalized briefing, highlighting to-dos and catching you up on what matters.
02
Engagement now decides where you land
Notice what these systems reward. Priority is inferred from relationships and behaviour: people you correspond with, brands you engage with, messages with a clear task or date. A business that mails thousands of people who never respond gives these systems little reason to rank it highly.
Spam complaints are the harder edge. Gmail asks senders to keep the spam rate shown in Postmaster Tools below 0.1 per cent and never to reach 0.3 per cent, and Yahoo sets the same 0.3 per cent ceiling for bulk senders. A smaller list that wants your email beats a large one that tolerates it, both in the AI views and at the spam filter.
03
Write for the summary, then for the reader
An AI summary is built from your words, so give it the right words early. Open with the point: what is on offer, for whom, until when. Keep the call to action and its link near the top rather than below three banners, and make sure anything important exists as live text, not only inside an image.
Subject lines should describe. For a hypothetical dental clinic in Kochi, 'Free gum check-ups in Kakkanad, Saturday 13 June' gives an assistant something accurate to restate; 'You won't believe this' gives it nothing. One purpose per email keeps the summary honest, because a single sentence cannot carry five offers.
| Old habit | What happens now | Do this instead |
|---|---|---|
| Teaser subject line | A summary describes the email in its own words | Say what it is: offer, place, date |
| The point below a banner | Summaries and previews draw on your text | Offer and link in the first two lines |
| Five offers in one newsletter | A one-line summary carries one idea | One purpose per email |
| Judging success on opens | Apple hides whether an email was opened | Track clicks, replies and enquiries |
| Mailing everyone you ever collected | Relevance sorting favours engaged senders | Prune people who never act |
04
The sender rules you cannot skip
Since February 2024 Gmail has required every sender to authenticate with SPF or DKIM, keep valid forward and reverse DNS records, use TLS and keep spam rates below 0.3 per cent. Senders of close to 5,000 or more messages a day to personal Gmail accounts must also use both SPF and DKIM, publish DMARC and align the From domain, and they had until 1 June 2024 to add one-click unsubscribe to marketing email. Gmail suggests honouring unsubscribes within 48 hours, Yahoo requires two days, and Gmail began ramping up enforcement in November 2025.
Microsoft's Outlook.com has required SPF, DKIM and DMARC since 5 May 2025 from domains sending more than 5,000 messages a day, and Microsoft said it would reject mail that fails rather than send it to junk. Most small businesses never reach these volumes, but the bulk rules are still the right standard, and Gmail says bulk sender status, once given, does not expire. If you send through a newsletter tool, ask it to confirm your domain's SPF, DKIM and DMARC records and that the unsubscribe header is switched on.
05
Measure what the machine cannot fake
Open rates stopped being trustworthy in 2021, when Apple's Mail Privacy Protection arrived with iOS 15 and began preventing senders from learning whether a message was opened. Inbox summaries make opens even less meaningful, because a reader can take in your offer from the preview without opening the email at all.
Judge email on clicks, replies, bookings and revenue, and tag every campaign link with consistent UTM parameters so your analytics can tell an email visit from a social one. Prune the list each quarter: anyone who has not clicked, replied or bought in six months gets one re-permission email, then leaves. Our notes on privacy-first analytics and attribution on small budgets cover the measurement side.
Sep 2021
Apple hides opens
Mail Privacy Protection ships with iOS 15.
Feb 2024
Gmail and Yahoo sender rules
Authentication, low spam rates and easy unsubscribes become requirements.
Oct 2024
Apple Intelligence in Mail
Inbox summaries and Priority Messages, in US English first.
May 2025
Gemini summary cards
Summaries on long Gmail threads for paid users, in English.
Jan 2026
Gmail's Gemini era
Free thread summaries in the US; AI Inbox with trusted testers.
May 2026
AI Inbox widens
Rolling out to Google AI Plus and Pro subscribers in the US.
06
What to do before your next campaign
- Check authentication. SPF, DKIM and DMARC on your sending domain, and one-click unsubscribe switched on in your email tool.
- Write the summary first. One sentence that would make a customer act, used as the opening line.
- Make the subject line describe. Offer, place, date. No teasers.
- Give each email one job. Split newsletters that try to sell three things.
- Put key facts in live text. Prices, dates and the call to action should never exist only in an image.
- Prune every quarter. One re-permission email to people inactive for six months, then remove them.
- Report on actions. Clicks, replies, enquiries and sales by campaign, not opens.
Sources
Current as of 29 May 2026. AI inbox features roll out by country, language and plan, so availability differs.