How AI Is Changing the Way You Need to Build Emails to Reach the Inbox

by Carol Springer | Jun 9, 2026

A practical look at what and how AI Previews being used by the major mailbox providers have done to impact deliverability. And what you need to do to make sure your campaigns actually reach the inbox.

How AI Changes How You Need to Build Emails for Delivery to Inbox

Short Summary of What You Will Learn: We wrote this article to help you with email deliverability. We explain the impact of AI Previews and how this impacts how to build emails. We explain how/why its important to lead with real text and a strong subject line. We recap how to pass SPF, DKIM, and DMARC. And finally we discuss other ways to keep your spam-complaint rate under 0.10% to 0.30% and the benefits of data hygiene and well segmented lists.

We have also summarized the action items from our learnings in a full checklist. You can access this checklist in two ways. You can download a PDF for easy access at any time. Or you can reference online in this supporting blog post Checklist for AI Era Inbox.

Background

We just attended the Salesforce Connections conference in Chicago. At the conference nearly every session addressed new AI capabilities across the Salesforce and Marketing Cloud family (including Sales Cloud, Account Engagement, Slack and Marketing Cloud Next). There is a great deal to be excited about especially what will be possible with native AI tools in Marketing Cloud Next.

But what stood out as immediately useful/actionable is this: the major mailbox providers have used AI to quietly change what it takes to consistently land your emails in your target’s inbox. There are three main issues that every team needs to immediately address to maintain and ensure successful delivery:

AI previews and how they change the way you need to build an email
Authentication and sender reputation
List quality

As positive news, even with all the changes occurring with AI , Salesforce data continues to confirm that email marketing and lead nurturing still produces one of the best and most cost effective ROIs for B2B companies. In this short article we will explain what has changed and what needs renewed strategic attention/focus to ensure email deliverability. We will also explain why it matters so you can make the right strategic decisions for your organization.

AI Previews: Build for the Machine That Reads First

Before a single human sees your email, an AI may have already read it and decided what it’s about. Apple Mail uses Apple Intelligence to write a short summary from the first few hundred words of your email and shows it in the inbox in place of your preheader. As an email marketer you can’t override it or turn it off. Gmail offers Gemini-generated summaries as well. These tools also help decide what’s most important inside the message, which means structure, content hierarchy, images, alt text, and the placement of your key information all matter more than they used to.

One useful detail from the sessions: Apple’s summary is built from your live body text and largely ignores your subject line, your preheader, and any text inside image alt tags. So how you assemble the top of your email now shapes the preview your reader sees before they decide to open. The encouraging part is that the same choices that help the AI also make your email more accessible to screen-reader users and easier for busy people to skim. Five practices make the difference. For more, see Salesforce’s tips for navigating AI email summaries and Litmus’s breakdown of what AI summaries mean for marketers.

1. Put the key message in the first few sentences

Lead with the single most important takeaway, such as the offer, the value, the reason to act, in your opening lines, not after a greeting and a paragraph of warm-up.

Why this matters: Apple Intelligence builds its inbox summary from the first few hundred words of your body copy. If those opening lines are “Hi there, hope you’re having a great week” or housekeeping text, that’s what the AI summarizes and that becomes the preview your subscriber judges before opening. Front-load the substance and the AI has something worth showing.

2. Use real text rather than text embedded in images

Keep your core message in live, selectable text. Don’t bake your headline, offer, or key copy into a graphic.

Why this matters: AI can only summarize text it can actually read it. Text trapped inside an image is invisible to it, just as it is to screen readers and, often, to spam filters. Image-only emails give the summary engine almost nothing to work with, and testing shows summary quality drops sharply for them. Don’t lean on alt text as a safety net, either: AI summaries frequently ignore it. Live HTML text is what carries your message. Alt text remains critical for accessibility, but today’s AI inbox summaries appear to rely primarily on the visible email content rather than the alt text attached to images.

3. Use a clear preheader

Write a specific, benefit-driven preheader that extends your subject line, however, your subject line needs to stand alone in case some never see your preheader. Do not use “View this email in your browser” or a string of empty filler.

Why this matters: The preheader is still the preview line in many inboxes and for every recipient who isn’t seeing an AI summary. A clear preheader earns more opens, and where AI summaries do appear, a focused top-of-email keeps your signal consistent. It’s a small field that quietly shapes a first impression.

4. Don’t stuff the top of the email with legal text, navigation, or “view online” links

Move boilerplate nav menus, legal disclaimers, “view in browser” out of the opening. Lead with the message; let the housekeeping sit lower or in the footer.

Why this matters: AI reads top-down and weights what comes first, so if the top of your email is a navigation bar and a disclaimer, that’s what can end up in the summary and that will be reader’s first impression. Clearing the top lets both the AI and your reader get to the point.

5. Use semantic structure: headings, bullets, and concise paragraphs

Organize the email with real headings, short paragraphs, and scannable lists rather than one dense block of copy.

Why this matters: Clear structure helps the AI understand your hierarchy and identify what’s most important, and it helps human readers skim and act. It’s also the foundation of accessibility. Screen-reader users navigate by headings so good structure serves the machine, the assistive technology, and the busy reader all at once.

Authentication and Sender Reputation: Now a Gate, Not a Best Practice

SPF, DKIM, and DMARC used to be the kind of technical hygiene that lived on someone’s “we should get to that” list. Not anymore. In plain terms, these are the records that prove an email actually came from you and wasn’t spoofed by someone else. Gmail, Yahoo, and Microsoft now treat them as baseline requirements. And now for higher-volume senders, mail that fails authentication is rejected, not just filtered to spam. A great campaign that fails authentication simply never arrives.

What these terms actually mean

SPF (Sender Policy Framework): a public list of the mail servers allowed to send email on behalf of your domain, so a receiving server can confirm your message came from an approved source. Google’s SPF overview.

DKIM (DomainKeys Identified Mail): a tamper-evident digital signature added to each message, letting the receiving server verify the email genuinely came from your domain and wasn’t altered in transit. Google’s DKIM overview.

DMARC (Domain-based Message Authentication, Reporting & Conformance): the policy that tells receiving servers what to do with mail that fails SPF or DKIM — deliver, quarantine, or reject — and sends you reports showing who is sending under your domain. Google’s DMARC overview.

Missing or misconfigured authentication is the single most common gap we see, and it’s usually invisible until deliverability quietly erodes. If you haven’t confirmed your domain is passing all three, that’s the first thing to check. See Google’s email sender guidelines and Microsoft’s requirements for high-volume senders (enforcement began May 5, 2025).

For a clear breakdown of the new bulk-sender rules and why this matters, see Validity’s guide.

List Quality Protects Everything Discussed Above

All of the above rests on list quality. Because providers reward engaged senders, consistently mailing inactive or invalid contacts actively drags down deliverability for your entire list — your engaged subscribers included. List hygiene has moved from housekeeping to strategy requirement. Regularly removing dead addresses, suppressing chronically unengaged contacts, and segmenting by real activity isn’t about a tidier database for its own sake; it’s about protecting the inbox placement of the people who do want to hear from you. This is also where clean, well-organized data in your CRM and marketing platform pays off directly. Data governance and data hygiene are becoming more important.

The 60-Second Deliverability Checklist

If you only do four things, do these. The rest of this guide explains the why behind each one.

Confirm your domain passes SPF, DKIM, and DMARC (this is now a hard requirement, not a nice-to-have).
Build every email with real text and a clear, standalone subject line.
Write a deliberate preheader — don’t let the platform invent one.
Mail engaged contacts; suppress and remove the rest on a regular schedule.

For a longer more comprehensive checklist download our PDF here or visit our blog post Or you can reference online in supporting blog post Checklist for AI Era Inbox.

The Bottom Line

AI is changing how people consume email, but deliverability is still won or lost through authentication, sender reputation, engagement, and list quality.

The encouraging part: most teams already own the tools to do all of this, and it’s usually a matter of operationalizing how you build emails, your authentication and DMARC monitoring, and your list hygiene, rather than buying anything new. If you’d like a second set of eyes on where your email program stands today, that’s exactly the kind of behind-the-scenes work we help our clients put in place at Gabriel Sales. We’re always happy to talk it through and staff the resources to help you if necessary.

About the Author

Carol Springer is a Founder at Gabriel Sales. She has been working at the inflection point of Marketing an Sales Operations implementing an optimizing Salesforce and Marketing Automation for the past 15 years. Carol has multiple Salesforce certifications leads the Denver Colorado Salesforce Marketers User Group and is a frequent Salesforce Speaker. Prior to focusing on Sales and Marketing Ops Carol was an award winning enterprise sales executive.

Sources & further reading

Email Deliverability Checklist for 2026: The AI-Era Inbox

by Marketing Team | Jun 8, 2026

Email deliverability is a critical so your campaign actually reaches the inbox instead of landing in Spam folder or the Promotions tab. In 2026, three things decide it: authentication (proving you are who you say you are), sender reputation (your track record with mailbox providers), and engagement (whether real people open, click, and reply). This email deliverability checklist walks through all six fundamentals and what’s changed now that AI summarizes the inbox.

Email Deliverability Checklist Download Image

Most deliverability advice still treats the inbox like it’s 2023. Many marketers chase the open rate, keep your list clean, and you’re fine. That world is gone. Gmail, Yahoo, and Microsoft now reject mail that fails authentication, open rate is no longer a reliable signal, and AI is starting to summarize your emails before a human ever reads them. The fundamentals below still decide whether you reach the inbox but several of them now work differently.

Run the first five sections against your process, and add the Pre-Send Check to every deployment. You can download a PDF for easy access and/or reference in the future here.

You can also read our short but comprehensive article for additional background and guidance. “How AI Is Changing the Way You Need to Build Emails to Reach the Inbox”

Guide and Email Deliverability Checklist

1. Authentication

❑ SPF is published and passing for your sending domain

❑ DKIM is enabled and signing your mail

❑ DMARC is published and aligned with SPF and/or DKIM

Why it matters: SPF, DKIM, and DMARC are the three records that prove your email genuinely came from your domain and wasn’t spoofed. Gmail, Yahoo, and Microsoft now reject (not just filter) unauthenticated mail from higher-volume senders. If these fail, the campaign never arrives.

2. Sender Reputation

❑ DMARC monitoring is in place and reviewed regularly

❑ Spam-complaint rate is tracked and held under 0.10% (and never approaching 0.30%)

❑ Sending volume is consistent. No sudden spikes from a cold domain or IP

Why it matters: Reputation behaves like a credit score. It is slow to build and quick to damage. It still decides Primary Inbox vs. Promotions tab vs. Spam. Mailbox providers want your spam-complaint rate under 0.10%; crossing 0.30% or you can land you in the spam folder for everyone.

3. Engagement

❑ Primary KPIs are clicks, conversions, and replies. Not just open rate alone

❑ Engagement is reviewed by audience segment, not just program-wide averages

❑ A re-engagement or sunset flow exists for declining subscribers

Why it matters: Mailbox providers place mail based on real engagement, so engagement is now a deliverability signal. It is no longer just a performance metric. Open rates have become unreliable because of privacy protections (like Apple Mail Privacy Protection) and AI inbox behavior that can pre-load or auto-open messages.

4. List Quality

❑ Invalid and bounced addresses are removed on a regular cadence

❑ Chronically unengaged contacts are suppressed or sunset

❑ Lists are segmented by real activity, not just by static fields

Why it matters: Mailing inactive or invalid contacts drags down deliverability for your entire list. This includes the subscribers who genuinely want to hear from you. Clean, activity-based segmentation can help to protect your engaged and core of your audience. Quality vs. Quantity is now a real strategic consideration.

5. Designing for the AI Inbox

❑ Emails are written so the core message survives being summarized to one or two lines

❑ The single most important call to action is unmistakable, not buried among several links

❑ Plain-text and accessible structure are prioritized so AI assistants can parse the content accurately

❑ Performance is reviewed with the assumption that open rate will keep degrading as a metric

Why it matters: Gmail, Outlook, and Apple are putting AI between your email and your reader. Increasingly, an assistant reads the message first and tells the human what it says. If your email only makes sense when read top to bottom by a person, it loses meaning the moment it’s summarized. Writing for the AI inbox is quickly becoming part of writing for deliverability.

6. Pre-Send Check (run on every deployment)

❑ Subject line stands on its own and leads with the email’s primary value

❑ The key message lands in the first few sentences

❑ Real text is used instead of text embedded in images, with alt text in place

❑ A clean preheader is set. The top isn’t stuffed with legal text, nav, or “view online” links

❑ Semantic structure is used: headings, short paragraphs, a scannable layout

❑ The AI-summary preview is reviewed to confirm an AI-generated summary would represent the message well

Why it matters: AI-generated inbox summaries can now replace your preview text, and AI decides which content matters most. Clear structure and a strong, self-contained subject line are what carry the message through.

Some Additional Email Deliverability FAQs and Tips

What is a good spam complaint rate for email?

Mailbox providers want your spam-complaint rate held under 0.10%. Crossing 0.30% is treated as a serious problem and can push your mail to the spam folder for your entire list, not just the people who complained.

Do Gmail, Yahoo, and Microsoft reject unauthenticated email?

Yes. For higher-volume senders, Gmail, Yahoo, and Microsoft now reject mail that fails authentication rather than simply filtering it. That’s why SPF, DKIM, and DMARC are no longer optional. Without them, the campaign never arrives.

Why are open rates unreliable in 2026?

Privacy protections like Apple Mail Privacy Protection and AI inbox behavior can pre-load or auto-open messages, which inflates and distorts open data. That’s why clicks, conversions, and replies are now the KPIs that matter, and why engagement (not opens) is the signal mailbox providers use to place your mail.

How do AI inbox summaries affect email marketing?

AI assistants in Gmail, Outlook, and Apple Mail can generate a short summary of your email and even replace your preview text. The practical effect is that an AI often reads your message before a human does. Emails with a clear subject line, a key message up front, and clean semantic structure summarize well; cluttered emails get misrepresented.

What’s the fastest way to improve email deliverability?

Start with authentication (SPF, DKIM, DMARC), because failing it stops delivery entirely. Then protect sender reputation by keeping complaint rates low and volume steady, and clean your list so you’re not mailing invalid or chronically unengaged contacts that drag down everyone else.

Streamline email deliverability in Salesforce, Marketing Cloud Account Engagement, Sales Cloud and/or Marketing Cloud Next

Knowing the checklist is one thing; operationalizing B2B deliverability inside Salesforce Marketing Cloud, Account Engagement (formerly Pardot), Marketing Cloud Next or Sales Cloud so authentication, suppression, and engagement-based segmentation run reliably every send can be daunting. That’s just some of the work Gabriel Sales does for B2B teams every day. See how we’ve helped clients tighten their marketing and sales operations in multiple ways in our case studies, or contact us to schedule some time to learn a little bit more about how we may be able to help.