You can write the best cart abandonment email in the world, but if it lands in spam, it's worth nothing. Deliverability is the foundation that everything else depends on.

Ecommerce stores face unique deliverability challenges. You're sending high volumes, mixing transactional and marketing emails, ramping up during promotions, and constantly adding new subscribers. Each of these can cause problems if you're not careful.

Here's how to keep your emails landing in the inbox.

The Basics: Authentication

Before anything else, make sure your email authentication is properly set up. This is non-negotiable.

SPF (Sender Policy Framework): Tells email providers which servers are allowed to send email on behalf of your domain. Your email platform should provide the DNS record to add.

DKIM (DomainKeys Identified Mail): Adds a digital signature to your emails that proves they haven't been tampered with in transit.

DMARC (Domain-based Message Authentication, Reporting, and Conformance): Tells email providers what to do with emails that fail SPF or DKIM checks.

If these aren't set up, you're at a huge disadvantage from the start. Most email platforms walk you through this during setup. Sequenzy handles deliverability setup as part of onboarding to make sure your authentication is right from day one.

Check your setup: Use tools like Mail Tester (mail-tester.com) or MXToolbox to verify everything is configured correctly.

List Hygiene

This is where most ecommerce stores go wrong. Your list grows through checkouts, popups, and signups. Not all of those contacts are good.

Remove hard bounces immediately. A hard bounce means the email address doesn't exist. Keep sending to it and email providers will penalize you.

Suppress long-term non-openers. If someone hasn't opened an email in 6 months, stop sending to them (or reduce to once a month at most). They're either not interested or your emails are going to their spam folder, and continuing to send makes the problem worse.

Watch for spam traps. Old, recycled email addresses sometimes become spam traps. They look like real addresses but exist solely to catch senders with poor list hygiene. The best defense is regular list cleaning.

Validate new signups. Use double opt-in or at minimum an email validation service to catch typos and fake addresses before they enter your list.

Clean before major campaigns. Before Black Friday, holiday sales, or any high-volume sending period, clean your list. Remove bounces, suppress non-openers, and validate questionable addresses.

Sending Patterns

How you send matters as much as what you send.

Be consistent. If you normally send 2 emails per week, don't suddenly send 5 per day. Email providers track your sending patterns and flag sudden spikes as suspicious.

Warm up gradually. When you move to a new email platform, start with your most engaged subscribers and gradually increase volume over 2-4 weeks. Don't blast your full list on day one.

Separate transactional and marketing. Use different sending domains or subdomains for transactional emails (order confirmations, shipping notifications) and marketing emails (campaigns, promotions). This way, if your marketing emails hit spam issues, your transactional emails aren't affected.

Watch your bounce rate. Keep it under 2% per campaign. Consistently higher bounce rates signal poor list quality.

Monitor complaint rates. If more than 0.1% of recipients mark your email as spam, you have a problem. This is the threshold that Gmail and other providers use.

Ecommerce-Specific Deliverability Issues

High-Volume Promotional Periods

During Black Friday, holiday season, and major sales, you'll send more emails than usual. Email providers know this is a high-spam period and are extra vigilant.

What to do:

Ramp up volume gradually in the weeks before
Prioritize your most engaged segments
Send your least engaged segment last (or skip them)
Monitor deliverability metrics in real time during your sale

Checkout Opt-In Quality

Many ecommerce stores collect email addresses at checkout with a pre-checked marketing opt-in box. This gives you volume but not quality. People often check out as guests with throwaway emails or don't realize they opted in.

Better approaches:

Make the opt-in checkbox unchecked by default
Set clear expectations: "Get exclusive offers and new product alerts"
Send a welcome email immediately to confirm engagement
Suppress contacts who don't engage with any of the first 5 emails

Product Image Emails

Ecommerce emails tend to be image-heavy (product photos, lifestyle shots, banners). This can cause deliverability issues.

Best practices:

Include real text content alongside images (not just images)
Use alt text for all images
Don't use a single large image as your entire email
Keep your image-to-text ratio reasonable (60/40 is a good target)
Compress images so they load quickly

Coupon and Discount Language

Certain words and phrases trigger spam filters more often. Be careful with:

ALL CAPS in subject lines
Excessive exclamation marks!!!
Words like "FREE," "GUARANTEED," "ACT NOW"
Dollar signs in subject lines ($$$)

You can still use these words, just don't pile them all into one email. "50% off everything this weekend" is fine. "FREE!!! BIGGEST SALE EVER!!! ACT NOW!!!! $$$" is not.

Engagement Metrics That Affect Deliverability

Email providers like Gmail use engagement signals to decide whether to put your email in the inbox, promotions tab, or spam folder.

Positive signals:

Opens and clicks
Replies
Moving an email from promotions to primary inbox
Adding your address to contacts

Negative signals:

Deleting without opening
Marking as spam
Never opening your emails

This is why segmentation matters so much for deliverability. Sending to engaged subscribers keeps your positive signals high. Sending to disengaged subscribers drags them down.

What to Do When You Hit Spam Issues

If your deliverability suddenly drops, here's a systematic approach to fixing it.

Step 1: Check your authentication. Make sure SPF, DKIM, and DMARC are all passing. Use Google Postmaster Tools to check your domain reputation.

Step 2: Check your bounce rate. A spike in bounces often precedes deliverability problems. Remove bounced addresses immediately.

Step 3: Check for spam complaints. Review your complaint rate in your email platform's dashboard. If it's above 0.1%, something in your recent emails upset people.

Step 4: Reduce your sending to engaged-only. For 2-4 weeks, only send to subscribers who have opened or clicked in the last 30 days. This rebuilds your positive engagement signals.

Step 5: Gradually re-add segments. Once your deliverability recovers, slowly bring back less-engaged segments. Add 10-20% more of your list each week.

Step 6: Investigate root causes. Did you recently change your email content, increase frequency, or add a large batch of new subscribers? Identify what changed and fix it.

Tools for Monitoring Deliverability

Google Postmaster Tools: Free. Shows your domain reputation, spam rate, and authentication status for Gmail specifically.

Your email platform's dashboard: Most platforms show bounce rates, complaint rates, and deliverability scores. Check these regularly.

Seed testing: Services like Mail Tester or GlockApps send your email to test inboxes across providers and tell you where it lands.

Inbox placement monitoring: Premium services that continuously monitor your inbox placement across providers.

Getting Started

If you haven't thought about deliverability before:

Verify your SPF, DKIM, and DMARC records are set up correctly
Set up Google Postmaster Tools for your domain
Remove anyone who hasn't opened an email in 6+ months from your active list
Check your bounce rate and complaint rate
Make sure transactional and marketing emails use separate sending identities

Good deliverability isn't something you set up once and forget. It requires ongoing attention. But the payoff is huge. If your emails actually reach the inbox, everything else in your email marketing works better.