How We Boosted Klaviyo Deliverability 20% for a Footwear Retailer

An open rate of 15% is a disaster.

When a leading Australian footwear retailer came to us, that’s what they were facing. Their open rates had plummeted from a healthy 35% in just a few weeks. Their emails were going straight to spam, spam complaints were climbing, and a crucial revenue channel was dying.

They knew they had a problem. They just didn’t know how deep it went.

Initial Klaviyo deliverability audit and diagnosis

The first step was to find the root cause. When deliverability tanks, it’s rarely one single thing. It’s usually a series of small cuts that finally cause a major bleed.

We started with a full-scale audit of their Klaviyo account. This is our standard process for any new client, but here we were looking for specific signals of poor sending reputation. We reviewed their historical campaign performance, list growth sources, and the technical email authentication setup.

The technicals were a mess. SPF and DKIM were in place but DMARC was missing. This is a common oversight, but it tells inbox providers like Gmail and Outlook that you aren’t fully in control of your sending domain.

Next, we audited their content and segmentation. We looked at every active flow and the last 90 days of campaigns. The content itself wasn’t terrible, but it was generic. The same message went to almost everyone. There was no personalisation based on past purchases or browsing behaviour.

Our audit uncovered four core issues: * Poor list hygiene: The client had never suppressed unengaged subscribers. Their main list was full of contacts who hadn’t opened an email in over a year. * Inconsistent sending: They would send five emails during a sale week, then go silent for three weeks. This erratic behaviour is a red flag for inbox providers. * No real segmentation: They had a “VIP” segment, but it was just based on total spend. They weren’t segmenting by engagement, purchase frequency, or product category. * Generic content: Subject lines and email copy were one-size-fits-all, leading to low engagement from the people who actually saw the emails.

These issues combined to destroy their sender reputation. We had a clear diagnosis. Now we needed a plan to fix it. If this sounds familiar, you can get a free Klaviyo audit from my team to see where you stand.

Our strategic approach to email deliverability improvement

Fixing deliverability isn’t about a single magic bullet. It requires a holistic strategy focused on rebuilding trust with inbox providers. Our plan had three main pillars.

Targeted segmentation for engaged audiences

First, we had to stop sending to unengaged people. This meant building a new segmentation strategy from the ground up. We moved beyond simple lists and created dynamic segments based on real customer behaviour.

We built segments for highly engaged users (opened or clicked in last 30 days), moderately engaged (31-90 days), and at-risk (91-180 days). This allowed us to send our best offers to the most receptive people first, generating positive engagement signals that inbox providers love. This kind of advanced Klaviyo segmentation is the foundation of good deliverability.

Ruthless list hygiene and re-engagement

You cannot be sentimental about your email list. A subscriber who hasn’t opened an email in 12 months is actively harming your ability to reach the subscribers who do want to hear from you.

We implemented a systematic suppression process. Anyone who hadn’t engaged in over 180 days was put into a final re-engagement flow. This flow offered a strong incentive to click and confirm they still wanted to receive emails. If they didn’t engage with that flow, they were suppressed. Permanently.

This is scary for a lot of founders. The client was hesitant to cut tens of thousands of subscribers. But we showed them the data. Those subscribers weren’t generating any revenue, and they were costing the brand money in both Klaviyo fees and lost deliverability.

Content relevance and sender reputation

With clean, engaged segments, we could focus on content. The goal was to make every email feel relevant and valuable to the person receiving it.

We used Klaviyo’s dynamic content blocks to personalise product recommendations based on browsing history and past purchases. We A/B tested subject lines relentlessly, finding that shorter, more direct lines consistently performed better. For this client, subject lines under 45 characters saw a 4-point lift in open rates.

We also optimised every email for mobile. Over 70% of their subscribers were opening on a mobile device. Simple, single-column layouts with clear calls-to-action made a significant difference to click-through rates.

Klaviyo implementation: overcoming deliverability challenges

The strategy was clear. The implementation required careful, methodical work inside Klaviyo.

First, we built the new segmentation structure. This involved creating over a dozen new dynamic segments that updated in real-time. We then created a new “sunset” flow to automate the suppression of unengaged subscribers .

Next, we overhauled their core flows. The welcome series, abandoned cart, and browse abandonment flows were all rebuilt. We changed the timing, refined the copy, and added dynamic content to make them more effective. The new welcome series, for example, had different paths for first-time visitors versus previous customers.

The biggest technical step was correctly configuring their email authentication. We worked with their IT team to implement a strict DMARC policy. This involved setting up the correct DNS records and monitoring the reports to ensure only legitimate emails were being sent from their domain. You can read more about this on Klaviyo’s own guide to understanding DMARC.

The main challenge was client education. They were worried about the list size shrinking. We had to consistently present the data, showing that a smaller, more engaged list would generate more revenue than a large, dead one. Our hands-on Klaviyo management involves this level of partnership. We used Klaviyo’s analytics to build a dashboard tracking open rates, click rates, and revenue per recipient for the new segments versus the old list. The numbers made the case for us.

Tangible results: 20% Klaviyo deliverability boost and beyond

The results came faster than we expected. Within 90 days, we had completely turned their email performance around.

The numbers speak for themselves. * Open rates climbed from a low of 15% to a consistent average of 38%. That’s more than double. * Click-through rates increased from 1.2% to 3.5%. * Spam complaint rate dropped from 0.4% to below 0.08%, well under the industry threshold. * Email-attributed revenue increased by 22% quarter-on-quarter, despite sending to a smaller list of people.

The biggest win was improved inbox placement. Using monitoring tools, we could see that their emails were now landing in the primary inbox for over 95% of their Gmail and Outlook subscribers, up from less than 60% when we started.

This wasn’t just a short-term fix. We built a sustainable system for maintaining list health and sending relevant content. The brand now has a stronger relationship with its customers and a more profitable email channel. You can see more of our results with other brands on our site.

Key takeaways for improving your Klaviyo deliverability

This case study highlights a few critical lessons for any eCommerce brand using email.

Deliverability isn’t a “set and forget” task. It requires constant attention. Here are the key actions you should be taking.

• Prioritise list hygiene. Be ruthless about suppressing unengaged subscribers. Anyone who hasn’t opened or clicked in 6 months is a candidate for suppression.
• Segment beyond the basics. Go deeper than purchase history. Use engagement data, website activity, and predicted customer lifetime value to create hyper-targeted audiences.
• Warm up new domains or IP addresses. If you’re starting fresh or making a big change, gradually ramp up your sending volume to build a positive reputation with inbox providers.
• Provide value in every email. Don’t just send promotions. Mix in valuable content, brand stories, and user-generated content to keep subscribers engaged.
• Monitor your metrics. Watch your open rates, click rates, bounce rates, and spam complaints like a hawk. A sudden drop in any of these is an early warning sign of a deliverability problem.

Making these changes can feel daunting, especially the decision to clean your list. But the long-term health of your most valuable marketing channel depends on it.

If you need help diagnosing and fixing these kinds of complex issues, our Klaviyo expert team does this work every day.