Holiday Deliverability Best Practices for Email Marketers


Since nothing about 2020 has been normal, we expect to see atypical holiday shopping patterns. With a significant decline in foot traffic in brick-and-mortar stores, Deloitte projects ecommerce sales to surge by 25 to 30%. As retailers rely on email during the holiday season, deliverability is more important than ever because the ISPs become more strict with filtering as senders change their audience, list size and cadence.

We have some guidance on how you can mitigate the risk of a deliverability issue with all of those factors in play.

Sender Reputation Is Key

With this influx in send volume, ISPs must make adjustments to how they accept and deliver mail. All senders are competing for more limited inbox placement, so ensuring your sender reputation is, and remains, healthy is critical.

Metrics that ISPs look at when scoring your sender reputation include:

  • User engagement
  • Invalid addresses (hard bounces)
  • User complaints
  • Spam trap hits
  • Drastic changes in send volume

What to Monitor to Avoid Deliverability Issues

Open rates should be consistent across the top ISPs. If one is significantly lower than the rest, you may have an inboxing issue at that top domain. Are soft bounce rates higher than usual across any major ISPs? That may mean they’re blocking your mail due to abusive metrics or poor sender reputation.

Specifically within Gmail, you can use the Postmaster Tools. If your IP and/or domain reputation dips below medium to low or bad, that is usually indicative of a sender reputation issue at Gmail, resulting in mail being filtered to the spam folder.

Other metrics to monitor to ensure you’re not at risk for deliverability issues include:

  • Hard bounce rates. If hard bounces are above 0.5%, check the audience you’re mailing.
  • Complaint rates. High complaint rates indicate that users do not like what you are sending, whether that’s content or frequency. Monitor complaint rates with each send.
  • Overall open rates for changes to the norm. Low open rates can show poorer engagement and play an important role in your reputation.
  • Opt-out rates. You don’t want to sacrifice your loyal list during the holidays. If opt-out rates rise, take a look at what you are doing and adjust.
  • Potential bots. While bots can hit sign up pages with email addresses across all ISPs, we tend to see bots hit with Chinese or Russian domains, such as,, and Any major spike in sign ups out of the norm should be investigated immediately. Proactively implement Google reCAPTCHA to eliminate the risk of a BOT attack.

Most holiday strategies involve sending to less engaged users or users at a more regular cadence, which often results in hard bounce and complaint spikes, and decreases in user engagement. If these metrics are atypical, it’s important to ensure your delivery and inboxing aren’t impacted.

Helpful Recommendations

With holiday deliverability nuances, we have some recommendations to keep in mind during the season.

  1. Don’t introduce any new lists to your ESP.
  2. Avoid mailing older lists you have not consistently mailed.
  3. Do not fully remove suppression lists. If you want to begin sending to lesser engaged users, slowly begin well before the holiday season starts. That way, issues can be mitigated before Black Friday.
  4. Be cautious of new acquisition sources. Test them prior to the holiday season and ensure they don’t result in hard bounces and complaints.
  5. Edit your signup and opt-out pages carefully.
  6. Be careful changing your sending cadence. ISPs will penalize you for an inconsistent spike in send volume, so increases in cadence should happen slowly. Provide preferences to allow users to opt down from increased marketing.
  7. Do not change your sending domain.

Download Delivering Results to the Inbox, our sister brand Sailthru’s ultimate deliverability playbook, to learn more about all the essentials, including the complex path messages take en route to the inbox, how deliverability drives revenue, the importance of sender reputation and more.


Liveclicker enables personalization at the moment of open. Our platform helps marketers adjust emails at any time—even after they reach the inbox—so your message is always relevant and impactful.


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