Inboxpass All guides

Guides

Holiday email: keep peak sends out of spam

1 November 2026

Holiday mail lands in spam for the same reasons as any other mail, only more often, because senders change their habits all at once. Volume jumps, old lists come back, and new tools get added in a hurry. The fix is to authenticate your domain before the first big send, raise volume in steps instead of overnight, and keep complaints well under 0.3%. This year Black Friday is 27 November and Cyber Monday is 30 November, so the time to check is now.

The DNS part is the part you can settle in an afternoon. A $129 Snapshot reads your SPF, DKIM, and DMARC records and tells you what to fix first, inside 24 hours. The rest of this guide covers the habits that matter once the records are right.

Why peak season is different

Mailbox providers judge a sender partly by its history. A domain that sends 2,000 messages a week and then sends 40,000 on a Friday looks different from the domain they knew. Google’s email sender guidelines say it plainly: increase sending volume slowly, send at a consistent rate, and avoid sudden volume spikes if you do not have a history of sending large volumes. The same page warns that suddenly doubling what you sent before could result in rate limiting or reputation drops.

Three other things tend to happen in November:

The 5,000-a-day line

Google’s sender guidelines FAQ defines a bulk sender as one that sends close to 5,000 messages or more to personal Gmail accounts within 24 hours. Mail from subdomains of the same primary domain counts toward the total. And a sender that crosses the line once is treated as a bulk sender from then on.

Bulk senders to Gmail need SPF and DKIM, a DMARC record that passes with an aligned domain, and one-click unsubscribe on marketing mail. Google’s FAQ also says that, starting November 2025, Gmail is ramping up enforcement on traffic that does not meet the requirements, with temporary and permanent rejections. So a holiday campaign that would have gone through with a warning two years ago can now bounce.

The other two large providers have similar rules:

Our guide to the Google and Yahoo sender requirements has the full list. If you think a big campaign might push you over, meet the bulk rules now. They cost little, and they cover you on the one day it counts.

Two weeks out: check the records

Do this before you build a single campaign.

  1. List every tool that sends as your domain. Your mailbox provider, newsletter platform, store, review requests, SMS-and-email apps, help desk, and invoices. Ask whoever set up the store what they added this year.
  2. Check that each one signs with DKIM on your domain. A tool that signs with its own domain passes DKIM, but that pass does not count toward DMARC. Our guide on setting up DKIM explains how to tell.
  3. Check SPF. One record, under ten DNS lookups. Adding a new tool’s include: is the most common way to break the limit without noticing. See fixing too many lookups.
  4. Check DMARC. You need a record at _dmarc.yourdomain.com, at least p=none, with an rua address so reports come back to you. Read a week of reports and confirm every tool on your list shows up as passing.

Hold off on tightening DMARC to quarantine or reject in the middle of November unless the reports have been clean for a while. A policy change right before your biggest send, with a tool you forgot about, can block real orders. Our guide to DMARC policies covers the timing.

Ramp volume in steps

Google does not publish a schedule for raising volume, so treat any specific percentage you read elsewhere as someone’s opinion. What Google does say is to start with a low volume to engaged users and increase it slowly over time, and to monitor delivery in Postmaster Tools as you go.

In practice, for a holiday plan:

One more point from Google: if you share an IP address with other senders, as most small stores on a newsletter platform do, everyone’s activity affects the reputation of that IP. You cannot control the other senders. You can control your list and your complaint rate.

Keep complaints low

The number that matters most in December is the share of recipients who mark your mail as spam. Google says to keep the rate in Postmaster Tools below 0.10% and never let it reach 0.30%. Yahoo uses 0.3% as its line. Google’s FAQ adds that a bulk sender above 0.3% is not eligible for mitigation help, and becomes eligible again only after seven days in a row below it.

The habits that keep complaints down are dull and they work:

Yahoo also says every DKIM domain should have an active complaint feedback loop, so you hear about complaints and can remove those people. Most newsletter platforms handle this for you. If you send from your own server, check that you are enrolled.

During the week

After Cyber Monday

Look at who complained and who never opened, and take them off before the December sends. Remove any trial tool you added for the season from SPF and stop its DKIM. Our deliverability checklist is a good list to work through in the quiet week after.

What none of this guarantees

Google says authenticated mail is less likely to be rejected or marked as spam. Less likely is the honest promise. Providers also weigh complaints, engagement, content, and history. Clean DNS removes the avoidable reasons for trouble, and a careful ramp keeps you from looking like a stranger on your busiest day.

Sources