By Steve Merrill, Founder of WRKNG Digital, June 16, 2026
Why Are Your Email Open Rates Dropping?
Your list is dying slowly. You just don't know it yet.
Most Shopify founders treat email as a set-it-and-forget-it channel. They add subscribers, send campaigns, and check revenue attribution. What they don't check is whether their emails are actually reaching inboxes. By the time open rates crater, the damage is already done.
Deliverability isn't a technical detail, it's the tax you pay for ignoring your list.
The good news: the fundamentals aren't complicated. They're just boring. And because they're boring, most founders skip them until they're standing in front of a suppressed domain wondering what happened.
What Is Email Sender Reputation and Why Does It Matter for Shopify Stores?
Inbox providers grade you. Every send you make contributes to a score that determines whether your emails land in the inbox, the promotions tab, or spam.
Google Postmaster Tools tracks your domain reputation in real time across four categories: spam rate, IP reputation, domain reputation, and feedback loop. According to Google Postmaster Tools documentation, a domain reputation of "Bad" means your mail will be rejected or heavily filtered. Most brands have no idea where they sit because they've never checked.
I've looked at this data across 40+ DTC email audits. The pattern is always the same. Founders are surprised. The data isn't.
Your sender score lives at the domain level. That means if you're sending from the same domain as your Shopify store, a bad email reputation affects everything, not just Klaviyo campaigns, but transactional order confirmations too. That's a serious problem.
What Bounce Rate Is Too High for a Shopify Email Program?
Hard bounces kill domains.
According to Klaviyo's deliverability documentation, a hard bounce rate above 2% is a red flag. Above 5% and you're in crisis territory. At that point, inbox providers have already started routing your mail to spam.
Klaviyo suppresses hard bounces automatically after one occurrence. That's good. The problem is soft bounces, temporary failures that accumulate quietly over months. A contact with five soft bounces is effectively dead. But they're still on your list. Still inflating your count. Still getting sent to.
Every email you send to an invalid or disengaged address is a vote against your own domain.
Audit your Klaviyo bounce data quarterly. Pull contacts with more than three soft bounces in the last 90 days. Suppress them. Don't wait for hard bounces to pile up before acting.
How Do Engagement Windows Affect Email Deliverability?
Gmail and Yahoo watch engagement closely. If your subscribers aren't opening, clicking, or interacting, inbox providers interpret that as a signal that your mail isn't wanted. They start filtering it before it even reaches the inbox.
The standard engagement windows used in Klaviyo segmentation are 30, 60, and 90 days. Contacts who haven't engaged in 90 days are already cooling off. Contacts past 180 days are functionally unresponsive.
Here's what that means practically. If you have 50,000 contacts in Klaviyo and 30,000 of them haven't opened anything in six months, you're not running a 50,000-person list. You're running a 20,000-person list and dragging a 30,000-person anchor that's actively hurting your inbox placement for the subscribers who actually want to hear from you.
Sending to unengaged contacts doesn't just waste money, it degrades deliverability for everyone on your list.
Segment aggressively. Keep your active sends tight. Run a sunset flow for the 90-180 day window. Give them one last shot to re-engage. If they don't, suppress them.
What Is a Sunset Flow and How Does It Protect Your Sender Score?
A sunset flow is a final re-engagement sequence sent to contacts who've gone quiet. Three to four emails over a few weeks. The goal is simple: either get them to click something, or get a clear signal that they're done.
A basic sunset flow might look like: a "we miss you" email, a last-chance offer, a "should we keep sending?" email with a direct link to stay subscribed. If they don't engage with any of them, you suppress. Done.
The Klaviyo platform makes this straightforward to build. The Klaviyo sunset flow documentation walks through the setup. What it can't do is make you build one. Most brands don't.
Not great. But fixable.
A sunset flow protects your sender score because it ensures you're only sending ongoing campaigns to people who've confirmed they want them. That engagement signal is what inbox providers use to grade you.
How Do Spam Complaint Rates Affect Klaviyo Deliverability?
Spam complaints are brutal. One complaint per 1,000 sends (0.1%) is the threshold where Gmail starts taking action against your domain. Above 0.3% and you're in serious trouble.
The causes are predictable. Sending too frequently. Sending irrelevant content to unengaged subscribers. Making it hard to unsubscribe. When people can't find the unsubscribe link, they hit "report spam" instead. That's on you.
Make unsubscribing easy. One click. No guilt trips. No "are you sure?" screens. The contacts who want to leave will leave. The ones you keep are worth keeping.
A subscriber who unsubscribes does zero damage. A subscriber who marks you as spam costs you inbox access for everyone else.
Check your spam complaint rate in Klaviyo's deliverability tab monthly. If it's creeping up, the first fix is always the same: tighten your sending to engaged-only segments.
What Domain and Authentication Setup Does a Shopify Store Need?
Authentication is the foundation. Without it, nothing else matters.
You need three things in place: SPF, DKIM, and DMARC. SPF tells inbox providers which servers are allowed to send email on behalf of your domain. DKIM adds a cryptographic signature that verifies the email wasn't tampered with in transit. DMARC tells inbox providers what to do when an email fails SPF or DKIM checks.
Klaviyo handles DKIM setup through their sending domain configuration. But DMARC is yours to configure. Most Shopify stores have SPF and DKIM set up because Klaviyo prompts you. DMARC is often missing entirely. That's a gap.
If you're not sure what's configured, check your DNS records. A DMARC policy of at least p=none with reporting enabled is the minimum starting point. Moving to p=quarantine or p=reject over time protects your domain from spoofing.
Same story with dedicated sending domains. If you're sending volume above 50,000 emails per month, you should be on a dedicated sending domain, not Klaviyo's shared infrastructure. Shared infrastructure means your reputation is partially tied to every other brand using those IPs.
FAQ: Email Deliverability for Shopify and Klaviyo
What is a good email deliverability rate for Shopify stores?
According to Klaviyo benchmarks, a healthy Shopify store should maintain a bounce rate under 0.5% and a spam complaint rate under 0.08%. If your open rates drop below 20% for a previously engaged segment, that's a signal your sender reputation is already degraded.
How often should I clean my Klaviyo email list?
Suppress unengaged contacts every 90 days at minimum. Anyone who hasn't opened or clicked in 180 days should be moved to a sunset flow or removed entirely. Klaviyo's own documentation recommends segmenting by 30, 60, and 90-day engagement windows to catch decline early.
What causes a drop in email sender score for DTC brands?
The most common causes are hard bounce accumulation, sending to unengaged contacts, and spam complaint rates above 0.1%. Google Postmaster Tools tracks your domain reputation in real time. Most founders only look after the damage is done.
Does suppressing contacts hurt my email list size?
Short term, yes. Long term, no. A smaller list of engaged subscribers outperforms a bloated list of ghosts every time. Inbox providers like Gmail reward senders whose contacts actually open and click. Sending to dead weight pulls your domain reputation down for everyone on your list.
What's the difference between a soft bounce and a hard bounce in Klaviyo?
A hard bounce means the email address doesn't exist or is permanently invalid. Klaviyo automatically suppresses hard bounces after one occurrence. A soft bounce is a temporary failure, a full inbox, a server timeout. Too many soft bounces from the same address signal a dead contact. Klaviyo suppresses after multiple soft bounces, but you should audit manually if you're seeing elevated rates.
If your email program is underperforming, deliverability is usually the first place to look, and the last place most founders check. Getting the fundamentals right isn't glamorous. But it's the difference between a channel that compounds and one that quietly decays.
If you want to see where your store stands across email, AI visibility, and organic search readiness, get your AI Commerce Readiness audit from WRKNG Digital. We look at the full picture, not just the parts that are easy to see.
