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In the summertime, everyone talks about school breaks, BBQs, and travel. But in the email marketing world? It’s time to discuss the winter holiday season. Now. Waiting only sets you up for a stressful and rushed peak season.

Q4 inbox competition is always high, and the stakes get higher every year. The 2026 Benchmark Report shows that global inbox placement rates (IPR) improved to 87.2%, but rejection rates spiked in Q4 as senders ramped up volume without doing the necessary maintenance and audience audits first.

We’re also seeing a lot of changes from Gmail, Yahoo, and Microsoft this year as they get stricter about enforcing their bulk sender requirements. Not to mention AI sorting and summaries are changing how subscribers interact with your email—a complete shift from years past.

Let this be the year you’re kind to your future self and avoid scrambling through outdated strategies by getting things in place in advance. What you do now—in the summer months—will get your sends into inboxes during Black Friday, Cyber Monday, and the rest of the holidays.

Table of contents

• Audit your authentication and infrastructure
• Clean up your list
• Build engagement signals
• Write for the AI inbox
• Plan the ramp-up
• Don’t wait until the last minute

Audit your authentication and infrastructure

SPF, DKIM, and DMARC are mandatory at Gmail, Yahoo, and Microsoft. These are non-negotiable. Ideally your DMARC is set to p=quarantine at a minimum, preferably p=reject. Confirm that all your sending domains and IPs are properly configured, including both marketing and transactional setups.

Enrolling in Google Postmaster Tools is a simple way to verify if your domain is compliant. It comes with a Compliance Status dashboard that tells you directly if there’s an issue. Enrolling in Microsoft SNDS and JMRP, as well as the Yahoo Sender Hub, will give you more actionable data points and direct insight into your reputation.

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Clean up your list now

Cleaning your list now with a validation tool helps you remove risky and invalid addresses and sets you up to reach your less engaged subscribers without tanking your reputation. Yahoo purges inactive accounts after just 12 months, Gmail after 24 months.

It’s admittedly tricky these days to segment based on engagement behavior, since metrics like opens are skewed by proxy opens. Look at click data but also expand out to purchase and site behavior to determine the healthiest segments of your list to prioritize.

Build engagement signals

Engagement is the most important trust signal with MBPs. Build those signals now to support and protect you in Q4 (and year-round too). Test your send calendar and cadence to find out if your sweet spot with your audience has shifted. For example, maybe they’re more engaged with you on Saturdays instead of Tuesdays.

Make sure you also have a valid reply-to address. Microsoft explicitly calls for one in its bulk sender guidance. As a bonus for setting this up correctly, a reply-to campaign is a simple engagement boost. Ask subscribers to reply to an email to win something, get a discount, or share feedback. Just make sure you have a good receiving bucket ready for the reply-to address.

If you don’t have one, build and then promote an amazing brand-specific preference center, so subscribers can self-select content and frequency. This will enable you to have a more targeted, and therefore a more profitable, peak season. That zero-party data from your preference center can give you the ability to send fewer, but more relevant emails, so subscribers aren’t fatigued and overwhelmed (annoyed ) by you.

Write for the AI inbox

AI inbox features are live. Gmail has Gemini, Apple has Apple Intelligence sorting, Yahoo has relevance sorting, and most subscribers’ inboxes are set up with AI summaries. Don’t design just for AI, of course—humanity is always more important—but realistically, AI has to be a huge consideration when planning your campaigns. Front-load your offer—don’t bury the CTA. Use clean, structured formatting so AI summarizes your email accurately.

Purposefully configure your Gmail Annotations—don’t rely on their auto-generated versions being correct. Gmail now has a testing environment to use, so you can actually see how it will render.

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Plan the ramp-up

In the 2026 Benchmark Report, we saw that global sending volume declined YoY for the first time. Senders who shifted to smaller, more targeted email lists saw better outcomes. Strategy and personalization are the way to go, not one-size-fits-all bulk sends.

It’s likely that email marketers will feel pressure to send a few full list sends during this period. A common theme each year is senders running into trouble when they suddenly spike their volume. Summer volume tends to be low compared to the rest of the year, and that sudden Black Friday campaign launch email is a huge red flag. MBPs don’t like sudden volume spikes.

Start your ramp-up in September, not October, to give MBPs a steady, trustworthy pattern to evaluate. Test your triggered re-engagement campaign, or build one if you don’t already have it, and actually suppress the people who don’t re-engage. If you’re feeling pressure to reach back too far into your list, try it first in very small increments. See if there’s any value in those subscribers or use the results to build a case for being a little more chill with your recency algorithm. If you wait to try to re-engage them, it will just get lost in the holiday clutter anyway. But validate that segment first, of course.

Don’t wait until the last minute

If you want to win Q4, start in Q2 or Q3. Authentication, list hygiene, engagement strategy, ramp-up, AI… It’s a lot, and it can’t wait until the last minute. This doesn’t even include the time to build out the creative, do render tests across platforms and devices, check dark mode and accessibility, etc.

If you’re looking for more insights on how consumers are using AI ahead of peak sales season, check out our Audiences Perception of AI report.

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