Email Deliverability for Ecommerce: A Fix-It Guide

You can write the best email in the world, but if it lands in spam, it doesn't exist. For ecommerce brands, deliverability isn't an abstract technical problem — it's lost revenue on every send.

We manage email for over a dozen ecommerce brands on Klaviyo. We've seen clients come to us with open rates below 20%, completely locked out of their customers' inboxes. We've also rebuilt those accounts back to 40-60% open rates through a process that's repeatable — not magic.

This guide covers everything an ecommerce brand needs to know about email deliverability: what actually matters, what's mostly myth, and how to fix it when things go wrong.

What Is Email Deliverability (and Why Ecommerce Brands Get Hit Harder)

First, the distinction that trips everyone up: delivery rate vs deliverability.

Delivery rate is whether the email was accepted by the receiving server. If it didn't bounce, it was "delivered." Most brands see 95%+ delivery rates and assume everything is fine.

Deliverability is whether the email actually reached the inbox — not the spam folder, not the promotions tab, not a black hole. You can have a 98% delivery rate and still have half your emails going to spam. Delivery rate is a vanity metric. Deliverability is what determines whether people see your emails.

Ecommerce brands are more vulnerable to deliverability problems than most senders because of how they use email:

• High volume: Promotional campaigns, flow emails, transactional emails — ecommerce brands send a lot.
• Promotional content: Discounts, product launches, and sale announcements are exactly the type of content spam filters scrutinize.
• Seasonal spikes: BFCM, holiday sales, and flash promotions create sudden volume increases that raise red flags.
• Rapid list growth: Pop-ups, checkout opt-ins, and giveaways add subscribers fast — but not all of them are engaged.

What "Good" Looks Like: Benchmarks From Our Client Base

Note: Open rates are inflated by Apple's Mail Privacy Protection, which pre-loads tracking pixels. The numbers above reflect that reality — a "40%" open rate today is roughly equivalent to a 25-30% open rate pre-MPP.

Why Your Emails Are Going to Spam

There are five real reasons ecommerce emails end up in spam. Most of the advice you'll find online obsesses over subject line words and image ratios. Those matter far less than these:

1. Sending to Unengaged Subscribers

This is the number one deliverability killer for ecommerce brands. Your list grows from pop-ups, checkout opt-ins, and giveaways. Over time, a large chunk of those subscribers stop opening, stop clicking, stop caring. But you keep sending to them.

Every time you send an email that gets ignored, deleted without opening, or marked as spam, inbox providers notice. Do it enough and they start routing your emails to spam — not just for that subscriber, but for everyone on that inbox provider.

The fix is consistent list hygiene: sunset flows that automatically suppress unengaged subscribers, and exclusion segments that keep them off your campaign sends. We cover the full setup in our automated list hygiene guide.

2. Missing DNS Authentication

SPF, DKIM, and DMARC are authentication records that prove to inbox providers that you're actually authorized to send email from your domain. Without them, your emails look like they could be from anyone — and inbox providers treat that as suspicious.

This used to be a bigger problem. Klaviyo now pushes you through authentication setup during onboarding. But we still see brands that skipped it, especially those who set up their accounts a few years ago before Klaviyo made it more prominent.

3. Shared Sending Domain

When you first sign up for Klaviyo, you're placed on a shared sending pool. That means your domain reputation is partially determined by other brands sending from the same pool. If someone else in that pool is blasting unengaged lists or getting spam complaints, it can drag your deliverability down too.

Every ecommerce brand should set up a dedicated sending domain, regardless of sending volume. It's one of the first things we do for every new client. The setup takes 15 minutes in Klaviyo — you add DNS records to your domain, and Klaviyo walks you through it.

4. Sudden Volume Spikes

Inbox providers expect consistent sending patterns. When your volume suddenly jumps — importing a new list, ramping up for BFCM, coming back from a sending pause — it triggers scrutiny.

This is especially common around Black Friday and Cyber Monday. Brands that normally send 3x/week to 50K subscribers suddenly send daily to their full 200K list. The spike alone can tank deliverability.

5. Poor Content Mix

This one is less impactful than the four above, but it still matters. The biggest thing is variety: you don't want to send all-image emails every time. Mix image-heavy designs with text-based emails, use a combination of formats, and avoid being one-dimensional.

Beyond that, most content-related deliverability advice is largely myth. Specific words in subject lines, link counts, and image-to-text ratios have a much smaller impact than sending behavior and list quality.

Email Authentication: SPF, DKIM, and DMARC for Klaviyo + Shopify

Authentication tells inbox providers that you are who you say you are. Three records work together:

• SPF (Sender Policy Framework): Lists the servers authorized to send email from your domain. Tells receiving servers "these IPs are allowed to send as us."
• DKIM (DomainKeys Identified Mail): Adds a digital signature to every email that proves it wasn't tampered with in transit.
• DMARC (Domain-based Message Authentication, Reporting & Conformance): Tells receiving servers what to do if SPF or DKIM checks fail — quarantine the email, reject it, or let it through.

Authentication Checklist for Ecommerce Brands

Shopify handles its own email authentication for transactional emails (order confirmations, shipping updates). But your marketing emails through Klaviyo need separate authentication — Shopify's setup doesn't cover it.

How to Improve Email Deliverability: The Ecommerce Playbook

If your deliverability is already good, this section is about keeping it that way. If you're in trouble, skip ahead to the recovery playbook.

List Hygiene

The single most important thing you can do for deliverability is stop sending to people who aren't engaging. Two mechanisms:

1. Sunset flows: Automated flows that detect when a subscriber stops engaging and either re-engages them or suppresses them. Once set up, they run without you.
2. Exclusion segments: Create segments of unengaged subscribers and exclude them from your campaign sends. This immediately improves your engagement rates without losing those subscribers permanently.

Engagement Signals That Actually Help

Inbox providers track how recipients interact with your emails. Positive signals include opens, clicks, replies, and moving emails from spam to inbox. Negative signals include deleting without opening, marking as spam, and consistently ignoring emails.

One tactic that works particularly well: get people to reply to your emails. When inbox providers see replies, they recognize it as a legitimate two-way conversation, not marketing spam.

The easiest way to do this in ecommerce: offer a discount in exchange for a reply. Instead of putting a discount code directly in the email, say "Reply to this email to receive your discount code." You can even use a pre-filled reply link that opens their email client with the message already composed — one click and they've sent a reply.

This works especially well in welcome series, where you're establishing your sender reputation with new subscribers. But you can use it in campaigns too — ask customers to reply with their story, their favorite product, or a photo. It's not gaming the system; it's genuine engagement.

Consistent Sending Patterns

Send consistently. Inbox providers prefer predictable patterns over erratic bursts. If you normally send 3 campaigns per week, keep doing that. Don't skip two weeks and then blast 5 emails in a day.

Deliverability: Flows vs Campaigns

Across our client base, flows consistently deliver at a higher rate than campaigns — typically around 10% higher open rates. The reason is straightforward:

Someone who just abandoned a cart or just made a purchase is far more likely to open your email than someone on your list who hasn't visited your site in weeks. That's why flows — welcome series, abandoned cart, post-purchase, browse abandonment — naturally have better deliverability.

Campaigns drive more raw volume, which is where most deliverability damage happens. The key is tightening your campaign audiences to exclude unengaged subscribers. For a deep dive on building the right flow architecture, see our complete guide to Klaviyo flows.

If your deliverability is already in trouble, we can help — book a free audit and we'll diagnose the problem.

The Recovery Playbook: Rebuilding Deliverability From Scratch

We had a client come to us with open rates below 20%. Click rates were in the gutter. Emails were going straight to spam. Here's the exact process we used to rebuild their deliverability back to healthy levels.

Step 1: Audit the Infrastructure

Before touching anything else, check the technical setup. In this client's case, the first thing we found was they didn't have their DNS records properly configured. No dedicated sending domain, no DKIM, no DMARC. They were sending from Klaviyo's shared pool with no authentication.

We migrated them to a dedicated sending domain and set up all authentication records. This alone doesn't fix the problem, but nothing else works without it.

Step 2: Shrink the Audience

This is the counterintuitive part. When your deliverability is tanked, you need to send to fewer people, not more. We reduced the sending audience to only the most engaged subscribers — people who had opened or clicked in the last 30 days.

The goal is to rack up positive engagement signals. When inbox providers see that nearly everyone you're sending to is opening and clicking, they start trusting you again.

Step 3: Gradually Expand

Once open rates stabilize at 40-50% with the smaller audience, you start carefully expanding. Add the next tier of subscribers — maybe 60-day engaged, then 90-day. Each time you expand, you watch the rates:

• If rates hold stable, expand further.
• If rates drop, hold at that level until they recover.
• Never expand and drop at the same time.

This process takes weeks to months depending on your sending volume. The initial infrastructure fixes show results quickly — we saw an immediate jump after setting up proper authentication. But rebuilding domain reputation is gradual.

Step 4: Boost Engagement During Recovery

While you're in recovery mode, use every tactic available to generate positive engagement signals. The reply-for-discount approach is especially effective here. Welcome series emails that prompt a reply, campaigns that ask for feedback, and discount codes gated behind a reply all help rebuild your sender reputation faster.

BFCM and Seasonal Spikes

Let's be honest: you're going to take a deliverability hit during Black Friday and Cyber Monday. Everyone is sending more, to broader audiences, with more aggressive content. There's no magic warm-up trick that prevents this.

What you can do:

• Accept it. Plan for it. Budget for slightly lower engagement during the BFCM window.
• Recover in Q1. January and February are naturally slower sending months. Use that time to tighten audiences, lower volume, and let your domain reputation recover.
• Don't panic. A temporary BFCM dip is normal. A sustained decline starting in BFCM that doesn't recover by February is a real problem that needs the recovery playbook above.

Per-Provider Deliverability: When One Inbox Is the Problem

Sometimes your overall metrics look fine, but one inbox provider is dragging you down. Klaviyo lets you break down performance by inbox provider — and when you do, you might find that your Gmail open rates are healthy at 50% but Yahoo is sitting at 15%.

In our experience, Yahoo and Outlook tend to be the strictest. Gmail is relatively more forgiving. When you spot a per-provider problem, the fix is the same as the recovery playbook but scoped to that provider: tighten your audience for Yahoo/Outlook subscribers specifically, rebuild engagement signals, and gradually expand.

How to Monitor Your Email Deliverability

Don't wait for a deliverability crisis to start paying attention. Here's what to check and how often:

Diagnostic Checklist (When Something Looks Wrong)

1. Check DNS authentication. Are SPF, DKIM, and DMARC properly configured? Are you on a dedicated sending domain?
2. Check Google Postmaster Tools. Look at your domain reputation and spam rate. Are you being flagged?
3. Check blocklists. Run your domain through MXToolbox to see if you're on any spam blocklists.
4. Review your rates. Look at open rates, bounce rates, and spam complaint rates over the last 30-90 days. Is there a trend?
5. Check per-provider performance. Break it down by inbox provider in Klaviyo. Is one provider (Yahoo, Outlook) significantly underperforming?
6. Review audience targeting. Are you sending to your full list or using engagement-based segments?

Ongoing Monitoring

Build deliverability into your regular email review. We recommend checking these monthly as part of a quarterly email audit:

• Overall open rate trend (should be stable or improving — see our email engagement benchmarks for reference)
• Bounce rate per campaign (should stay under 2%)
• Spam complaint rate (should stay under 0.1%)
• Google Postmaster domain reputation (should be "High")
• List growth vs suppression rate (healthy lists grow and shrink simultaneously)

The Most Overblown Deliverability Advice

There's one piece of deliverability advice we see everywhere that actually hurts ecommerce brands: only send to 30-day or 60-day engaged subscribers.

Yes, tighter audiences improve your engagement rates. But if you're only ever emailing people who opened in the last 30 days, you're leaving money on the table. A subscriber who last opened 45 days ago isn't dead — they might be waiting for the right product, the right offer, or the right timing.

The brands that over-index on engagement and under-index on revenue end up with great open rates and mediocre revenue. Deliverability is a means to an end, not the end itself. The goal is to send to the widest audience you can while maintaining healthy deliverability — not to chase the highest possible open rate. For a better approach to segmentation, see our guide on segmenting by purchase behavior instead of engagement.

FAQ

What is a good email deliverability rate for ecommerce?

A healthy delivery rate is above 95%. But delivery rate alone doesn't tell you about inbox placement. Focus on open rates as a proxy: 40-60% across flows and campaigns (accounting for Apple MPP inflation) indicates good deliverability. Below 30% is a warning sign.

How do I check my email deliverability in Klaviyo?

Klaviyo has a deliverability tab under Analytics that shows delivery rates, bounce rates, and spam complaints. You can also break down performance by inbox provider. Supplement this with Google Postmaster Tools for your Gmail reputation and MXToolbox for blocklist checks.

Why are my Klaviyo emails going to spam?

The most common reasons: sending to unengaged subscribers without exclusion segments, missing DNS authentication (SPF/DKIM/DMARC), still using Klaviyo's shared sending domain, or a sudden volume spike. Check authentication first, then look at your audience targeting.

How long does it take to fix email deliverability?

Infrastructure fixes (DNS, dedicated domain) show results within days. Rebuilding domain reputation through audience tightening and gradual expansion takes 2-8 weeks depending on your sending volume and how damaged your reputation is.

Does Shopify email have deliverability issues?

Shopify's built-in email tool handles authentication for transactional emails automatically. For marketing emails, most serious ecommerce brands use Klaviyo or another dedicated ESP, which gives you more control over authentication, sending domain, and audience management.

What's the difference between email delivery rate and deliverability?

Delivery rate measures whether an email was accepted by the receiving server (didn't bounce). Deliverability measures whether it actually reached the inbox vs the spam folder. You can have a 98% delivery rate and still have most of your emails landing in spam.