Email Deliverability Checklist for Ecommerce Brands in 2026

Most deliverability problems are not technical mysteries.

They are usually caused by:

• sending to people who do not want the email
• sending too often
• sending to unengaged contacts
• poor list acquisition
• missing authentication
• ignoring complaints

Deliverability is largely a consequence of behavior.

Here is the checklist we work through.

By Emiel Dingemans, Founder of Magicianly

The Quick Checklist

1. Authenticate Your Sending Domain

You need:

• SPF
• DKIM
• DMARC

Google requires email authentication for senders to Gmail accounts and documents its requirements in its email sender guidelines.

This is a baseline requirement, not an optimization.

2. Use a Branded Sending Domain

Sending from a shared or default provider domain means your reputation is not fully your own.

Klaviyo documents branded sending domain setup in its sending domain guidance.

The wider platform setup is covered in Klaviyo email deliverability.

3. Align Your From Address

Send from your real brand domain.

Avoid:

• free mailbox providers as the from address
• unrelated domains
• domains customers do not recognize

Recognition affects both filtering and complaint behavior.

4. Meet Bulk Sender Requirements

Google applies additional requirements to senders who send close to 5,000 or more messages per day to Gmail accounts, including authentication, one-click unsubscribe and keeping spam rates low, described in Google's bulk sender guidance.

Most established ecommerce brands are bulk senders.

5. Keep Spam Complaints Low

Google asks senders to keep the reported spam rate below 0.10% and to avoid ever reaching 0.30% or higher.

In practice this means:

• do not email people who never asked
• make unsubscribing easy
• do not increase frequency without watching complaints
• suppress complainers

6. Set Up Postmaster Tools

Google Postmaster Tools gives visibility into spam rate and domain reputation for Gmail recipients.

If you send meaningful volume to Gmail, you should be able to see this data.

7. Do Not Use Purchased or Scraped Lists

This is the fastest way to damage a sending reputation.

It also creates:

• complaints
• spam traps
• bounces
• legal risk
• worthless list growth

8. Collect Consent Honestly

Your signup form should make clear:

• what the subscriber gets
• who is sending
• how to opt out

Consent obtained by confusing the subscriber produces complaints later.

9. Suppress Hard Bounces

Most ESPs handle this automatically.

Confirm it is actually happening, especially after:

• migrations
• imports
• integrations
• manual list uploads

10. Watch Soft Bounces Too

Repeated soft bounces to the same address can indicate a deeper problem.

Klaviyo documents its bounce handling in its bounce documentation.

11. Suppress Repeat Complainers

If a subscriber marks your email as spam, they should not continue receiving campaigns.

This protects reputation across the whole list.

12. Segment Campaigns by Engagement

Sending every campaign to your entire list is one of the most common deliverability mistakes we see.

Better:

Highly engaged

Send frequently.

Moderately engaged

Send regularly.

Low engagement

Send selectively.

Long-term unengaged

Send rarely, then sunset.

See Klaviyo segmentation strategy for how we structure these audiences.

13. Do Not Rely Only on Opens

Open data has become less reliable because of privacy features that pre-load images.

Use a mix of signals where available:

• clicks
• site activity
• purchases
• form submissions

14. Sunset Long-Term Inactive Profiles

A subscriber who has not engaged in a year is unlikely to become a customer because you emailed a fifteenth promotion.

We cover the process in how to clean an email list in Klaviyo.

15. Try Re-Engagement Before Removal

Before suppressing, you can attempt:

• a short re-engagement sequence
• a preference update
• a clear opt-out

Some subscribers will return. Most will not.

16. Audit Forgotten Flows

Old automations quietly send bad email.

Common problems:

• expired promotions
• discontinued products
• broken links
• outdated brand voice
• wrong audience filters

Flows send continuously. They deserve continuous review.

17. Control Frequency Deliberately

More email is not automatically more revenue.

The tradeoffs are covered in email fatigue and frequency.

18. Avoid Sudden Volume Spikes

Going from occasional sends to daily sends to your entire list is a reputation risk.

Increase gradually.

19. Warm New Domains and New Accounts

If you are:

• migrating ESP
• using a new sending domain
• restarting a dormant list

ramp volume gradually, starting with your most engaged subscribers. Klaviyo documents this process in its warming guidance.

20. Be Careful With Reactivation Blasts

A large "we are back" send to a list that has not been emailed in a year is a classic way to create complaints.

Start small. Start with your best contacts.

21. Make Unsubscribing Easy

Hidden unsubscribe links do not reduce unsubscribes.

They increase spam complaints.

A spam complaint is worse than an unsubscribe.

22. Offer Preference Options Where Useful

Some subscribers do not want to leave. They want less.

Options can include:

• fewer emails
• specific topics
• product categories
• pause

23. Keep Signup Sources Clean

Audit where subscribers come from:

• popup
• footer form
• checkout
• giveaway
• third-party list
• event

Low-intent sources tend to produce low-quality engagement.

24. Watch Giveaway and Sweepstakes Growth

Giveaway subscribers often want the prize, not the brand.

If you use giveaways, monitor those subscribers as their own cohort.

25. Monitor Provider-Level Performance

Compare performance across major mailbox providers.

A sharp drop at one provider often points to a reputation problem rather than a content problem.

26. Watch Deliverability Metrics in Your ESP

Klaviyo provides deliverability reporting and guidance for diagnosing issues in its deliverability documentation.

Look at trends, not single sends.

27. Do Not Chase Spam Word Lists

Modern filtering is far more concerned with reputation and engagement than with whether you wrote the word "free".

Spend your effort on list quality, consent, relevance and frequency instead.

28. Review on a Cadence

Deliverability is not a one-time setup.

Review:

Weekly

Campaign performance and complaint signals.

Monthly

Engagement segments and list growth quality.

Quarterly

Authentication, flows, sunset policy and frequency.

What We See Most Often

Sending to everyone

The single most common cause of declining ecommerce email performance we encounter.

No sunset policy

Lists grow, engagement falls and reputation slowly erodes.

Unreviewed flows

Automations quietly sending outdated offers for months.

Frequency without segmentation

More volume applied to a list that was already fatigued.

Our Verdict

Deliverability is mostly a behavior problem, not a technical one.

Get the technical foundation right once:

• authentication
• branded sending domain
• clean bounce handling

Then manage the part that actually moves reputation:

who you send to, how often, and whether they want it.